Readers should note that definitions of terms in the Glossary for the most part reflect the way in which terms are used in this book. Terms may have other, or broader, definitions in other areas of biology.
The formal names of important individual genes and proteins are generally given as the abbreviation (if relevant) followed by the full name. Gene names are in italics; protein names are not italicized. Terms for individual genes/proteins are as they appear at first mention in the book, which may be as the gene or the protein.
Side or face of an organ orientated away from the apex of the plant, e.g., the lower surface of a leaf.
ATP-driven transporters that move diverse molecules (e.g., peptides, glutathione conjugates) across membranes.
Model showing how each of the four types of floral organ is determined by different combinations of regulatory genes.
Hormone with major roles in the response to water deficit and the imposition of seed dormancy.
Shedding of plant organs such as leaves and fruits, dependent on programmed cell separation in a specific zone of a petiole, stem, or pedicel.
For pigments, e.g., phytochrome and chlorophyll, plot of radiation wavelength versus energy absorbed.
Genetically uniform line of a species, initially isolated from a wild-type population then maintained by self-fertilization.
Acquisition of tolerance to a severe stress following exposure to a mild stress of the same type.
Compound released from plant wounds that attracts pathogenic Agrobacterium species.
Protein that polymerizes to form the filament component of the cytoskeleton.
Symmetry around a central point. In flowers, a radially symmetrical arrangement of floral organs.
Symbiosis between a host angiosperm and the nitrogen-fixing actinomycete bacterium Frankia.
Rapid, transient change in membrane potential that can propagate across a tissue, usually triggered by an external stimulus.
Transport of molecules or ions across a membrane against a concentration and/or electrical gradient, often in exchange for protons; as distinct from passive transport.
Side or face of an organ orientated toward the apex of the plant, e.g., the upper surface of a leaf.
Line through an organ from the upper, adaxial to the lower, abaxial side. Also called dorso–ventral axis.
Roots that develop from a part of the plant other than the primary root.
Tissue in stem and root cortex containing contiguous air spaces.
In plant transformation, introduction of Agrobacterium carrying DNA of interest into a plant by pressure or vacuum treatment.
In seeds, the cell layer that surrounds the endosperm.
Multi- or unicellular photosynthetic eukaryotes lacking leaves and vascular tissues that generally inhabit aquatic environments.
Class of diverse N-containing plant compounds, mainly with defensive roles. Some have important pharmacological properties.
One of two or more variant forms of a gene that can be present at a given locus.
Having a set of chromosomes acquired by combination of whole chromosome sets of two (or more) different species.
Artificial Intelligence system that predicts the 3D structure of a protein from its amino acid sequence.
A class of bacteria in the phylum Pseudomonadota (Proteobacteria).
Electron transport chain of the inner mitochondrial membrane that transfers electrons to the alternative oxidase. See also cytochrome pathway.
Production of variant messenger RNAs from a single gene by different patterns of exon inclusion.
Prevailing natural conditions (e.g., of temperature, atmospheric composition), as opposed to experimentally imposed conditions.
Small, often repeated, structural element within a protein that is conserved in a particular group or family of proteins and may have a defined biological function.
(Of a protein or lipid) Having both hydrophilic and hydrophobic regions or domains.
Maximum displacement of a wave form from a baseline, e.g., of transcript or protein abundance in a circadian rhythm.
Large α1,4-, α1,6-linked glucan that makes up 70 to 80% of most starch granules.
Nonpigmented plastid specialized for starch storage.
α1,4-linked glucan with a small number of α1,6 linkages that makes up 20 to 30% of most starch granules.
Life processes in the absence of oxygen.
Metabolic pathway that “tops up” an intermediate in another pathway.
Flowering plants with seeds enclosed in an ovary.
Plants that complete their entire life cycle within one year.
Completely devoid of oxygen.
In chloroplasts, array of protein-bound chlorophyll molecules in the thylakoid membrane associated with the core complex of a photosystem.
Signaling or transport directed away from the source of a stimulus or transportable cargo; as distinct from retrograde signaling, transport.
Component of a stamen in which pollen is produced.
In bryophytes, organ of the gametophyte that produces male gametes.
Glycosylated flavonoid derivatives that constitute the red, blue, and purple pigments of plant organs.
Molecules toxic to other organisms; term usually applied to specific inhibitors of microbial growth or metabolism.
In a direction perpendicular to a nearby surface; as distinct from periclinal.
Proteins synthesized under cold stress that inhibit the nucleation of ice crystals in the plant apoplast.
Redox compounds that scavenge potentially damaging reactive oxygen species by reducing them.
In the ovule, cells located opposite the point at which the pollen tube enters the embryo sac.
Membrane proteins that exchange two or more different substrates across a membrane.
Transcription factor with roles in plant development. Also major transcription factor family with AP2 DNA-binding domains structurally homologous to that of the transcription factor APETALA2.
Inhibition by the growing shoot apex of the outgrowth of axillary buds on the stem.
Curved form adopted by the upper hypocotyl and cotyledons of dark-grown seedlings.
Groups of cells in the shoot and root apex that divide to generate the primary tissues of the plant body; as distinct from intercalary meristem.
Line from the top to the bottom of an organ or plant.
Asymmetric organization of a cell or tissue along the apical–basal axis; the apical domain differs from the basal domain with respect to its properties and/or functions.
Reproduction by formation of seeds without fertilization.
Region of a plant tissue outside the plasma membranes, consisting largely of the cell walls. See also symplast.
Structure produced on a plant surface following spore germination of some pathogenic fungi. See also penetration peg.
Channel proteins that allow gated movement of water and other small uncharged molecules across membranes.
Possession of a tree-like structure.
Highly branched structure formed by the hyphae of mycorrhizal fungi after penetration of host plant cells.
Domain of life consisting of ubiquitous, largely unicellular organisms superficially resembling bacteria but more closely related to plants.
Study of past human–plant interactions using plant remains from archaeological sites. Also called paleoethnobotany.
In bryophytes, organ of the gametophyte that produces female gametes.
In seed plants, cell that undergoes meiosis to produce the haploid cells that give rise to pollen or ovules.
Reproduction that does not involve fertilization. See also apomixis.
High-energy compound formed in photosynthesis and respiration that provides energy for cellular functions.
Protein complexes in chloroplast thylakoid and inner mitochondrial membranes that catalyze ATP synthesis, energized by electrochemical gradients across the membranes.
Self-sustaining metabolic cycle, able to maintain a given flux while permitting withdrawal of intermediates.
Self-phosphorylation by a protein kinase.
Having a set of chromosomes acquired from duplication of the whole chromosome set of a single ancestral species.
Organisms that make their own organic compounds from inorganic precursors, using light or chemical energy.
Proteins that inhibit auxin signaling by binding to auxin response factors, thus preventing activation of auxin-responsive genes.
Proposed explanation linking auxin transport to the growth pattern of veins during leaf and stem development.
DNA sequence in the promoter of auxin-responsive genes that binds auxin response factors.
Transcription factors that activate auxin-responsive genes by binding to auxin response elements.
Hormones involved in many growth and developmental processes.
Organism unable to synthesize particular components essential for growth, so dependent on exogenous sources of the components.
Failure of a pathogen to establish disease on a normally susceptible host due to host activation of effector-triggered immunity.
The region between the upper side of a leaf petiole or a branch and the stem to which it is attached.
Bud that develops from an axillary meristem, in an axil.
Meristem located in a leaf axil that gives rise to an axillary bud. Also called lateral meristem.
In plant breeding, a cross between an F1 hybrid and one of its parents.
Differentiated form of a rhizobial bacterium in the nodule cells of a host plant.
Disease of rice caused by the gibberellin-producing fungus Gibberella fujikuroi. Also called foolish seedling disease.
Gametes produced through meiosis that contain equal numbers of chromosomes; as distinct from unbalanced gametes.
Plant species on the earliest branches of the angiosperm phylogenetic tree.
Plant species on the earliest branches of the eudicot phylogenetic tree.
See intercalary meristem.
Transcription factor structural motif that recognizes specific DNA sequences. Also a class of transcription factors.
Plants that grow vegetatively in their first year then flower, set seed, and die in their second year.
Symmetry on either side of a single axis, mirror symmetry. Also called zygomorphy.
Transverse division of a plastid, mitochondrion, or bacterial cell by constriction then separation, forming two daughter cells.
Agrobacterium-mediated plant transformation system in which the vir genes and the T-DNA components of the Ti plasmid are separated on two different plasmids that can be propagated in the same bacterial cell and transferred together into a plant cell.
Community of microorganisms (often bacteria, archaea, fungi) surrounded by a secreted matrix of polysaccharides and proteins.
Use of computational techniques to analyze and interpret large sets of biological data.
Conversion of gaseous nitrogen to ammonia by bacteria possessing a nitrogenase enzyme.
The mass of organisms in a specified area or volume.
Pathogens that grow in association with host plants without killing infected cells prior to pathogen reproduction.
Male and female parents contribute equal numbers of chromosomes to the fertilized zygote; as distinct from uniparental.
Structure formed by paired homologous chromosomes during prophase I of meiosis.
Occurring in the boreal zone, between latitudes of 50° and 70° north and having a subarctic climate.
Hormones involved in many plant processes, often in conjunction with other classes of hormone.
Protein produced by Bacillus thuringiensis that is toxic to insects. Also called Cry protein.
The ring of photosynthetic cells that surrounds the vascular bundle in a C4 leaf.
Transcription factor structural motif that recognizes specific DNA sequences. Also a class of transcription factors.
Pathway of photosynthetic carbon assimilation in most plant species, in which atmospheric CO2 is assimilated directly by Rubisco.
Plants that carry out C3 photosynthesis.
Polyphyletic group of species in which the photosynthetic CO2 compensation point is lowered by leaf anatomical features that promote recapture of photorespiratory CO2.
Pathway of photosynthetic carbon assimilation in about 3% of plant species. Atmospheric CO2 is assimilated by PEP carboxylase, products of which are used to generate a high CO2 concentration in Rubisco-containing cells.
Plants that carry out C4 photosynthesis.
Genes encoding components of the light-harvesting antennae associated with photosystems in thylakoid membranes.
Calcium in a diphenyl EDTA–calcium complex, from which it can be released by light pulses. Used to study calcium signaling.
Regular spikes of cytosolic Ca2+ concentration that form part of rhizobial and mycorrhizal symbiosis signaling pathways in root cells.
Undifferentiated masses of cells, derived and maintained in in vitro culture. Hormone treatments promote differentiation into plants.
Polysaccharide consisting of β1,3-linked glucose units, found in phloem sieve tubes, plasmodesmata, and healing wounds.
Autocatalytic metabolic pathway in chloroplasts that assimilates atmospheric CO2 and generates triose phosphate for sucrose synthesis.
See crassulacean acid metabolism.
Meristem between the phloem and xylem of stems, responsible for secondary thickening. It produces new phloem on its outer face and new xylem on its inner face.
Methylated guanosine residue added to the 5’ end of an RNA transcript during maturation.
In Asteraceae, broad inflorescence receptacle that bears numerous, tightly packed flowers (florets).
The protein coat surrounding the nucleic acid of a virus.
Incorporation of carbon from CO2 (inorganic carbon) into complex organic molecules via photosynthesis.
Removal of carbon from the global carbon cycle through burial of organic and inorganic carbon-containing materials in sediments.
Difference in the ratio 12C:13C (Δ13C) between plant material and atmospheric CO2, caused by diffusional and Rubisco discrimination against 13CO2 relative to 12CO2.
Rubisco-containing polyhedral protein shells in cyanobacteria, responsible for their carbon-concentrating mechanism.
Plants that gain nitrogen and other nutrients by trapping and digesting animals.
Terpene-derived pigments: protective functions in photosynthesis and responsible for color in many red and yellow fruits and flowers.
Female reproductive structure of a flower, comprising ovary, style, and stigma. The fourth whorl of a flower.
In grasses, a complex structure (the grain) in which maternal tissue layers are fused to the outer layers of the seed.
In roots, lignified, impermeable zone on the radial and transverse anticlinal walls of the endodermis.
Entry of gas from adjacent air spaces into xylem vessels. See also embolism.
DNA molecule produced by reverse transcriptase using RNA as a template.
Region of cytosol located immediately inside the cell wall, in which the cytoskeleton is primarily located.
The sequence of phases through which a cell passes between one cell division and the next. See also G1 phase, G2 phase, S phase, M phase.
Precursor of the new cell wall that forms between daughter cells during plant cell division. See also phragmoplast.
Wall that surrounds the cells of plants, fungi, and bacteria, enclosing the plasma membrane and cell contents.
Long polymers of β1,4-linked glucose units that associate to form microfibrils, the major component of the plant cell wall.
Rosette-shaped plasma membrane protein complex of cellulose synthases, giving rise to 18 cellulose polymers that associate to form a microfibril.
Geographical location in which a species or group of plants is believed to have first evolved.
In plant reproduction, binucleate cell in the female gametophyte: its nuclei fuse with a sperm nucleus to generate the endosperm.
In a shoot apical meristem, the central region that generates new cells to populate the peripheral zone.
Barrel-shaped microtubular structures from which the spindle forms during division in most animals, fungi, and algae but not in plants.
Region of the chromosome at which the spindle attaches during mitosis and meiosis.
Region of the sporophyte tissue around the developing ovule from which two outgrowths initiate and then expand to form integuments that envelop the gametophyte.
Proteins that mediate the correct folding of other, specific proteins but are not components of their final structure.
Formation of a complex between a metal cation and an organic compound, involved in e.g., solubilization of iron prior to uptake by roots.
Energy that is released or consumed during breakage and reforming of bonds in biochemical reactions.
Model describing how ATP generation in chloroplasts and mitochondria is driven by an electrochemical gradient across a membrane, set up by transfer of electrons along an electron transport chain.
Points at which crossing over and exchange of chromosome segments occurs between non-sister chromatids of homologous chromosomes during meiosis.
In plants, a mosaic tissue or organ made up of patches or layers of two or more genetically different types of cells.
Polymer of N-acetylglucosamine in the cell walls of fungi and exoskeletons of insects.
Pigment that absorbs light energy in photosynthesis, located in the thylakoid membranes of chloroplasts.
Dissipation of excess excitation energy from chlorophyll molecules as fluorescence.
Chlorophyll-containing plastid in which photosynthesis takes place.
Inner and outer membranes that surround the chloroplast. Other types of plastids have similar envelopes.
Having a yellowish or pale green color due to a low chlorophyll content.
Proposal that plant tropic growth (toward or away from a stimulus) is due to differential distribution of auxin in the organ concerned.
One of the two copies of a replicated chromosome formed in mitosis or meiosis.
Complex of DNA and histone proteins of which chromosomes are composed.
Shortening of a chromosomal region due to tight packing of chromatin.
Looping of a chromosome that brings non-adjacent DNA sequences into close proximity.
Molecular moiety that changes structural conformation when it absorbs light.
Plastid in which pigments (typically red or yellow carotenoids) are synthesized and stored.
Change in the order of sequences along one or more chromosomes.
Single, large molecule of DNA containing an array of genes and associated proteins.
Number of chromosomes present in a nucleus.
Separation of duplicated chromosomes and paired homologous chromosomes during mitosis and meiosis respectively, followed by their movement to opposite poles during cell division.
Series of interlocked feedback loops that generates endogenous oscillations of transcript and protein abundance with a periodicity of 24 hours.
24-hour rhythm (of e.g., protein abundance, leaf movement, scent production) imposed by the endogenous circadian clock.
Plant viruses that, when ingested by insects, pass through the gut wall and reach the salivary glands via the circulatory system.
A short, specific DNA sequence in a gene that is bound by a transcription factor or other regulatory proteins.
Group of species consisting of a common ancestor and its descendants.
Tree diagram that shows evolutionary relatedness of species within a clade.
Self-assembling protein that coats some vesicles during transport between cellular compartments.
Self-fertilization occurring within an unopened bud.
Stage in ripening of some fruits, associated with large metabolic changes including sugar accumulation and a high respiratory rate.
Experimental use of genetically marked cells to study how their descendants contribute to organ development.
Sector of an organ composed of daughter cells derived from a genetically marked cell.
Root distortion and consequent poor growth in Brassica species due to infection by the phytomyxean pathogen Plasmodiophora brassicae.
Dense clusters of short lateral rootlets in some plants tolerant of nutrient-poor soils, notably species in the Proteaceae.
In aquatic cyanobacteria, green algae, and hornworts, concentration of CO2 for photosynthesis by uptake of bicarbonate followed by its conversion to CO2 by carbonic anhydrase contained within a discrete compartment with a very high Rubisco content.
Single cell with multiple nuclei, formed by nuclear division without cell division.
Evolution of complementary traits in two different species that results from reciprocal effects on each other’s evolution.
Nonprotein component required for the activity of an enzyme, e.g., a metal ion or a compound containing a redox group.
Hydraulic explanation of the mechanism of the upward movement of water in the xylem.
Alkaloid drug that binds tubulin and inhibits the formation of microtubules; used in doubled-haploid production.
Central region of the root cap.
Combined action of multiple transcription factors to allow integrated responses to multiple inputs.
In evolution, an ancestral species from which two or more present-day species arose.
Common elements of the two similar signaling pathways involved in formation of rhizobial and mycorrhizal symbioses with plants.
Cells adjacent to the sieve elements of the phloem, connected to the sieve elements by plasmodesmata.
Compounds (e.g., proline, betaines, polyols) that modulate cellular osmotic potential and protect proteins and membranes, often produced under water deficit. Also called osmoprotection, osmolytes.
CO2 Compensation Point: Intercellular CO2 concentration at which CO2 assimilation in photosynthesis equals CO2 loss through photorespiration and respiration.
Light Compensation Point: Light intensity at which CO2 assimilation in photosynthesis equals CO2 loss through respiration.
Components of the electron transport chain in the inner mitochondrial membrane. See also cytochrome pathway, cytochrome c oxidase.
Leaf consisting of a number of separate leaflets attached to a single rachis.
The permeability of a root to water; a measure of the ease with which water can flow from the soil into the xylem.
Asexually produced spores of ascomycete fungi.
See gymnosperms.
A process by which plasmid DNA is transferred from one bacterium to another.
Taking place or existing in an organism at all times; as distinct from inducible.
Phenotype that shows continuous or graded rather than discrete, discontinuous variation within a plant population (e.g., height).
Independent evolution in different species of processes or structures that fulfill the same function.
Main group of angiosperms, which diversified later than the three groups that constitute the basal angiosperms.
In photosynthesis, a protein–chlorophyll complex in the thylakoid membrane that contains a photosystem reaction center.
Histone octamer and the ~146 bp of DNA wrapped around it.
Protein that associates with transcription factor(s) bound to DNA to form a repressive complex that prevents gene expression.
In woody stems, outer suberized cell layers, arising from a cork cambium (phellogen) that lies between cork and the phloem.
In plants, parenchymatous cells (cortical parenchyma) between the epidermis and endodermis of a root or stem.
Embryonic leaves that develop during embryogenesis. In some species, they are storage organs and may become photosynthetic upon germination.
Photosynthetic specialization in which CO2 is assimilated as malate via PEP carboxylase at night then released by decarboxylation to supply CO2 for photosynthesis when stomata are shut during the day.
Most widely used system for gene editing in plants. Derived from a naturally occurring system in bacteria and archaea where it is a defense component.
Inward folds of the mitochondrial inner membrane.
Agricultural practice of growing different crops in a field each year, on a cycle of several years.
Creation of hybrids by crossing one plant with another of a different variety or species.
See recombinant chromosomes.
Transfer of pollen from the flower of one individual to the flower of another individual of the species.
Galls formed on susceptible host plants during infection with Agrobacterium tumefaciens.
Compound protecting cell structures at low/freezing temperatures.
Flavoprotein blue-light receptors, involved in regulation of the photoperiodic flowering time pathway and photomorphogenesis.
A distinct variety of a crop plant generated by plant breeding and maintained in cultivation.
Cup-like structure consisting of fused bracts that holds the kernels of maize and teosinte.
Waxy layer of complex hydrocarbon polymers covering the aerial surfaces of plants.
Polymers that are components of the outer cuticle, consisting of esters of fatty acids and long-chain alcohols.
Polymeric component of the cuticle, consisting of a network of long, cross-linked fatty acid molecules.
Oxygen-producing, photosynthetic bacteria that can also assimilate nitrogen.
Plant metabolites that break down to release hydrogen cyanide when the tissues containing them are damaged.
In leaves, electron cycling around photosystem I that drives ATP synthesis without NADP+ reduction.
Proteins that stop, prevent, or reduce the activity of cyclin-dependent protein kinases.
Cyclin-activated kinases that regulate the cell cycle by phosphorylation of various cell-cycle proteins.
Proteins that form complexes with, and thus activate, cyclin-dependent protein kinases.
Chloroplast thylakoid-located protein complex involved in transfer of electrons from photosystem II to photosystem I.
Protein complex of the inner mitochondrial membrane (complex IV) that catalyzes reduction of oxygen to water.
Very large family of heme-containing enzymes with broad substrate specificity, catalyzing diverse reactions including hydroxylations in various biosynthetic pathways.
Electron transport chain in the inner mitochondrial membrane, transferring electrons to cytochrome c oxidase.
Study of the structure and inheritance of chromosomes.
Division of the cytoplasm between daughter cells during cell division, following division of the nucleus.
Hormones with major roles in the control of cell division and differentiation.
All the material excluding the nucleus and vacuole in the interior of a living cell, bounded by the plasma membrane.
Genomes of chloroplasts and mitochondria.
Inheritance of traits determined by the plastid or mitochondrial genomes, rather than the nuclear genome.
Maternally inherited inability to produce functional pollen due to a mutation in the mitochondrial genome.
Cytoplasmic cylinder that surrounds the desmotubule in plasmodesmata.
System of cytosolic filaments and microtubules involved in many cellular processes including karyo- and cytokinesis, cell expansion, and cell wall deposition.
The portion of the cell cytoplasm outside the organelles.
The two cells produced by mitotic division of a single cell.
Species in which the time of flowering is not responsive to photoperiod.
Antifungal peptides produced by plants in response to attack by necrotrophic pathogens.
Process by which an organ becomes detached from the plant body at an appropriate stage in the plant life cycle; zone in a stalk or pedicel in which programmed cell-wall changes lead to dehiscence.
A conserved amino-acid sequence involved in gibberellin signaling, found in a subset of GRAS family proteins.
Loss of the organized three-dimensional structure required for biological function.
Cylindrical structure in a plasmodesma that connects the endoplasmic reticulum of adjacent cells.
Growth pattern that produces a genetically determined number of organs.
Aquatic, unicellular microalgae with silicon-containing outer walls. Diatoms make up a large fraction of oceanic phytoplankton.
An RNase that catalyzes cleavage of double-stranded RNA to produce small RNAs of 21–26 nucleotides.
Regular pattern, rhythm, or cycle with a period of 24 hours.
Process whereby a cell, tissue, or organ acquires its mature structure and function after it has completed its growth.
Having male and female flowers on different individual plants.
Having two homologous copies of each chromosome.
Phenotype for which individuals in a population fall into non-overlapping categories (e.g., two different flower colors).
Plants with mutations that cause defense responses in the absence of a pathogen.
Bond formed by oxidation of adjacent –SH groups, forming an S–S bridge, e.g., between cysteine residues of proteins.
Conserved domain in a protein with affinity for specific DNA sequences. See also protein domain.
Enzyme that catalyzes the replication of DNA molecules.
See replication.
Conserved short nucleotide sequence in DNA, often present in multiple copies, often with a specific biological function.
Unconscious selection by early farmers of variants of wild plants amenable to cultivation.
Gene variant that confers a specific trait in either a homozygous or heterozygous state.
Period of biological inactivity of a plant, propagule, or seed, usually in conditions unfavorable for growth (winter, drought, etc.).
See adaxial–abaxial axis.
In angiosperms, fusion of one sperm cell to the egg cell and a second sperm cell to the central cell nucleus, generating a zygote and an endosperm precursor, respectively.
Technique whereby seedlings grown from haploid cells are rendered diploid then grown into homozygous plants. Used to create pure-breeding lines from crosses of genetically different parents in one generation.
Formed by complementary base-pairing of two RNA strands to give rise to a double-stranded structure.
Family of transcription factors implicated in responses to water deficit and other environmental stresses.
Plant that sheds its leaves and becomes dormant during a dry season.
Enzyme complex catalyzing the ubiquitination of specific proteins, rendering them substrates for degradation by a proteasome.
Group of plants within a species that is adapted to a particular set of environmental conditions.
Symbiotic associations between basidiomycete fungi and plant roots in which fungal hyphae form a sheath around the root.
Parasites living on the outer surface of their hosts.
A molecule, structure, or process occurring in a location in a plant in which it is not normally found.
Pathogen-produced molecules that interfere with and suppress plant pattern-triggered immunity.
Plant immune response triggered by cytoplasmic NLR receptors upon detection of pathogen effector proteins.
Gradient of ion concentration and electrical charge across a membrane.
Radiation with electrical and magnetic components, including visible and UV light, X-rays, infrared, and heat.
Molecule that can accept electrons from and donate electrons to other electron carriers or enzymes.
Series of membrane-bound components that catalyze electron transfer from an electron donor to a final electron acceptor.
Surface or secreted pathogen molecules that trigger plant defense mechanisms. See also PAMPs.
Air lock in a xylem vessel, blocking fluid movement. See also cavitation.
In angiosperm seeds, the embryo arises from the zygote and develops root and shoot meristems, a hypocotyl, and cotyledon(s) by maturity.
Technique involving removal of an immature embryo from a seed and its in vitro culture to produce a mature plant.
Angiosperm female gametophyte contained in the ovule; the structure in which the egg cell and subsequently the embryo develop.
Development of the embryo, from the zygote to seed maturity.
Constantly present in, and largely restricted to, a particular geographical region.
Inner cell layers of the valve of a silique.
Cell layer surrounding the vascular cylinder of roots and stems.
Intracellular membrane system comprising nuclear membrane, endoplasmic reticulum, Golgi apparatus, tonoplast, and associated vesicles.
Symbiotic associations between fungi and plant roots in which hyphae penetrate the root and form arbuscules in the root cells.
Parasites living within the bodies of their hosts.
Microorganism living within the body of a plant.
Network of membrane tubules and flattened sacs in which proteins and lipids are modified then exported to other endomembrane compartments. Rough ER has surface-bound ribosomes and is involved in protein glycosylation, smooth ER is involved in lipid synthesis and modification.
Chromosome replication without cell division, resulting in polyploid cells.
In angiosperms, a triploid tissue formed from fusion of the nucleus of a sperm and the central cell of the female gametophyte during fertilization.
Proposal that chloroplasts and mitochondria originated from bacterial endosymbionts in a proto-eukaryotic cell.
Symbiotic relationship in which one organism lives inside another.
Cell layer beneath the epidermis of a developing anther.
Short, gene-associated DNA motifs specifically recognized by transcription factors.
In circadian biology, synchronization of the internal circadian clock with external rhythms, typically with day–night cycles.
Heritable forms of a gene that have the same nucleotide sequence but different chromatin modifications.
Cell layer that forms the boundary between an organ or organism and the surrounding environment.
An alteration in gene function that is maintained during cell division but is not caused by a difference in DNA sequence.
A plant that grows on another plant as a support but does not derive nourishment from it.
Disease of the ears of cereals and grasses caused by Claviceps fungi: infected ears produce toxic alkaloids.
Reaction on a metabolic pathway with a large negative free energy change, making it effectively irreversible in a cell.
In hypoxia or anoxia, metabolism of sugars to generate ATP via glycolysis with ethanol as an end product.
Mutagenic agent routinely used to generate mutant plant populations for forward genetic screens.
Gaseous hormone with diverse roles in processes including seedling development, fruit ripening, seed germination, abscission, and senescence.
Exaggerated growth and pale color characteristic of dark- or shade-grown plants.
Plastid in dark-grown leaf tissue, lacking photosynthetic capacity.
Region of a chromosome with loosely packed chromatin and a high content of active genes; as distinct from heterochromatin.
One of the two main groups of angiosperms. Seedlings usually have two cotyledons, plants typically have netted leaf venation and flowers with twofold or fivefold symmetry; as distinct from monocots, monocotyledons.
Organisms of the domain Eukarya, in which the genetic material is contained in a membrane-bounded nucleus; as distinct from prokaryotes, bacteria, archaea.
Outer wall of pollen grains, consisting of sporopollenin. See also intine.
Part of a gene that is transcribed into an RNA transcript and is represented in the mature messenger RNA; as distinct from intron.
Cell wall proteins that influence wall elasticity through modulation of hydrogen bonding of its polysaccharide components.
Existing at the present day; as opposed to extinct.
Cell wall glycoproteins that are typically rich in hydroxyproline.
In circadian biology, the proposal that an external signal promotes or represses a particular process only when its occurrence coincides with a specific phase of the circadian rhythm.
Occurring on the outside of a structure; as distinct from intrinsic.
“Forms of the species,” taxonomic grouping used in fungal pathogen biology.
Plants resulting from a cross between two parental lines.
Second generation from a genetic cross, usually derived from self-pollination of first-generation (F1) plants.
Able to adjust processes reversibly in response to particular changes in conditions; as distinct from obligate.
Electromagnetic radiation with wavelengths between 700 nm and 750 nm.
See vascular cambium.
Long hydrocarbon chain with a terminal carboxyl group. Saturated fatty acids have no double bonds, unsaturated fatty acids have double bonds in the hydrocarbon chain, omega-3 fatty acids have a double bond 3 carbons from the methyl terminus.
Enzymes that catalyze the introduction of double bonds into fatty acids.
Plastidial protein complex that catalyzes the synthesis of fatty acids from acetyl-CoA.
Diverse family of proteins associated with the SCF E3 ubiquitin ligase that mediates ubiquitination of specific proteins destined for proteasomal degradation.
In a pathway or process, negative or positive regulation of a specific step by a later intermediate or end product.
In a pathway or process, negative or positive regulation of a specific step by an earlier intermediate.
Iron-sulfur proteins that mediate redox reactions in some metabolic pathways.
Redox reactions that reductively activate Calvin–Benson cycle enzymes using electrons from photosystem I.
In seeds, protein that forms a shell around a core of ferric iron and ferric oxide–phosphate complexes.
Fusion of male and female gametes to form a zygote, from which a new organism develops.
Elongated, thick-walled cells associated with the xylem and phloem that add rigidity to the vasculature. Also called sclerenchyma.
Protein that is the principal constituent of the bacterial flagellum.
Thread-like appendage enabling motility in some classes of microorganisms including many bacteria.
Flavins that can undergo oxidation–reduction reactions as enzyme cofactors and can absorb blue light. FAD and FMN are chromophores of the cryptochrome and phototropin receptors, respectively.
Classes of phenylpropanoid with roles as e.g., protective pigments and signals in plant symbiotic interactions.
See FLOWERING LOCUS C.
Plant transformation method for Arabidopsis in which the inflorescence is dipped in a suspension of Agrobacterium cells carrying the DNA of interest.
Genes controlled by flowering time pathways that induce flowering and/or confer floral meristem identity.
Group of dividing cells arising from an inflorescence meristem, from which the organs of the flower develop.
Genes encoding transcription factors that control the identity of the four types of floral organs: sepals, petals, stamens, and carpels.
Time at which flowering is initiated by a flowering time pathway in a plant that has acquired competence to flower.
Individual flower in a tightly packed inflorescence, e.g., in daisy-like flowers of the Asteraceae.
Name given by early researchers to the hypothetical substance generated in leaves that moves to the shoot apex to induce flowering. See also FLOWERING LOCUS T.
Gene encoding an inhibitor of flowering: some flowering-time pathways act by epigenetically blocking FLC expression.
Gene encoding a protein synthesized in the leaf vasculature under inducing conditions that moves via the phloem to the shoot apex to induce flowering.
See angiosperms.
Received light measured as photons per unit area.
See chlorophyll fluorescence.
Applied to gene identification methods using natural or induced mutants of the species concerned. See also reverse genetics.
In genome evolution, loss of many of the duplicated genes following whole genome duplication.
Mutation in a gene sequence that inserts or deletes a number of bases that is not a multiple of 3, disrupting the normal reading frame.
Experimental enrichment of CO2 above a crop or native vegetation plot in otherwise natural conditions.
In circadian biology, treatment with either continuous light or continuous dark in constant conditions: without entrainment.
Polysaccharides composed of fructosyl units, often with terminal glucose residues.
In angiosperms, the mature ovary (or ovaries) and associated, fused maternal plant parts.
Tubulin-like proteins forming an internal, membrane-attached ring during binary fission in bacteria and chloroplasts.
Case in which two or more genes have overlapping functions and are not individually necessary for the function.
Single-cell or filamentous multicellular heterotrophic eukaryote in the kingdom Fungi.
In plant reproduction, stalk that connects the mature ovule to the carpel placenta.
In wood, cells in the vascular cambium that give rise to phloem and xylem.
Mathematical model that links experimentally determined aspects of photosynthetic biochemistry with measurements of leaf gas exchange. It underpins research on e.g., the impact of climate change on crop productivity and global carbon cycling.
Gap phases of the cell cycle. Changes in preparation for division occur in G2 phase.
Constituents of chloroplast thylakoid membranes, with one or more galactose residues on position 3 of the glycerol backbone.
A specialized haploid male (sperm) or female (egg) cell that fuses with another gamete (sperm with egg) to form a diploid zygote.
The haploid phase of the plant life cycle, in which gametes are produced.
Mechanism of self-incompatibility in which the pollen-associated SI proteins are products of the haploid gametophyte. See also self-incompatibility.
Segment of DNA encoding a protein or an RNA with a specific function, and its associated regulatory sequences.
Attribution of likely function to individual genes in a genome sequence, using experimental and bioinformatic tools.
Process by which additional copies of a gene are generated in the genome.
See genome editing.
Production of an RNA transcript from a gene. Term may also include the translation of the transcript into protein.
Closely related genes within a genome, often arising from gene duplication followed by sequence divergence.
Explains the genetic interactions between genes encoding effector molecules in pathogens and cognate genes encoding disease resistance proteins (R proteins) in their plant hosts.
Interruption or suppression of gene expression at the transcriptional or translational level.
See transcription.
Set of proteins required for RNA polymerase recruitment and activation during initiation of transcription.
Cell from which sperm cells arise during pollen development.
In a chromosome, distances between genes or markers calculated from the frequencies of recombination during reproduction.
Preferential inheritance of a particular gene with other genes caused by their close proximity on the same chromosome and consequent failure to assort independently at meiosis. See also linkage drag.
Map showing the relative positions of genes and genetic markers on a chromosome.
Arbitrarily defined single-copy DNA sequence whose presence in the genome can be monitored.
Variation in allelic forms or sequence of a gene or genes in a population of a species.
Genetic content of the chromosomes in a plant nucleus or organelle (e.g., chloroplast, mitochondrion), or in a bacterium.
Process generating targeted modifications to a known gene or other DNA sequence in the genome. See also CRISPR.
Representation of the spatial order and physical distances separating genes on the chromosomes of a fully sequenced genome.
The DNA sequences of all of the chromosomes that constitute a genome.
The amount of DNA in the haploid complement of chromosomes that constitutes a genome, usually measured in Mbp or Gbp.
In the endosperm, epigenetically determined expression of either maternal or paternal alleles of particular genes following fertilization.
The specific combination of alleles present in an organism.
Processes occurring from seed imbibition to the point at which the radicle penetrates the seed coat.
Collection (store) of extant genetic diversity of a species of crop or wild plant, often as seeds.
Hormones that control the extent of organ expansion and growth through cell expansion, among other functions.
Global cycling of inorganic and organic forms of carbon, largely between the atmosphere, soils, the biosphere, and the oceans.
Global cycling of nitrogen between atmospheric N2 and fixed N in the air, soil, water, and biosphere.
A class of storage proteins found primarily in seeds.
Polymers of glucose.
Formation of sugars from noncarbohydrate compounds, such as fatty acids and amino acids.
Sulfur-containing compounds in the Brassicaceae that are converted to toxic isothiocyanates and nitriles upon tissue damage.
In grasses, bracts in inflorescences that form the husk (chaff) in which cereal grains are enclosed.
Tripeptide antioxidant with roles in SO42- assimilation, cellular redox balance, and protection against oxidative stress.
Oxidation–reduction cycle that controls levels of potentially toxic H2O2 by its reduction to water.
Storage proteins found in wheat grains.
General term for carbohydrates.
Membrane lipids with fatty acyl groups on positions 1 and 2 of the glycerol backbone, and a polar group on position 3.
Mitochondrial enzyme complex that, in conjunction with serine hydroxymethyltransferase, catalyzes the conversion of glycine to CO2, ammonia, and serine in the photorespiratory cycle.
Pathway in which hexose phosphate is metabolized to generate ATP, NADH, biosynthetic precursors, and pyruvate.
Plant species unable to grow in saline soils.
Molecule with a sugar group attached by a glycosidic bond.
N-glycosylation: Addition of a sugar to an asparagine residue in a protein.
O-glycosylation: Addition of a sugar to a serine or threonine residue of a protein.
Metabolic pathway that converts two molecules of acetyl-CoA to one molecule of succinate during gluconeogenesis from lipids.
A type of peroxisome found mainly in germinating, lipid-storing seeds, in which the glyoxylate cycle is located.
Compound used as a herbicide that inhibits an enzyme of the shikimate pathway.
Endomembrane component: stacked vesicles in which e.g., proteins and glycans are modified prior to transport to other cellular locations.
Joining of a plant part (e.g., shoot, bud) to another plant, usually of the same or a closely related species, so that they grow together.
In chloroplasts, stacked regions of thylakoid membranes; as distinct from stromal thylakoids.
Transcription factor family involved in developmental processes and stress responses, with a conserved C-terminal GRAS domain.
Growth of a plant part at a physiologically determined angle to the gravitational vector.
Protein from the jellyfish Aequorea that fluoresces green in blue light; the GFP gene is used as a reporter gene.
Technological and agricultural innovations that gave large increases in cereal grain yields between the 1940s and the 1970s.
Tissues of the plant body excluding the epidermis and the vascular cylinder. See also parenchyma.
In plants, metabolic pathway in which ammonium is assimilated into amino acids by glutamine synthase (GS) and glutamine–2-oxoglutarate aminotransferase (GOGAT).
In leaves, a pair of specialized epidermal cells that control the pore size of a stoma. See also stoma (plural stomata).
Exudation of xylem fluid from hydathodes on the margins of leaves.
Seed plants that do not produce flowers; e.g., pines and cycads.
Female reproductive organ of a flower, composed of carpels.
Industrial synthesis of ammonia from gaseous nitrogen and hydrogen: the source of inorganic nitrogenous fertilizers.
Root proliferation caused by infection with Agrobacterium rhizogenes.
Time after its synthesis at which there is a 50% probability that a given molecule (e.g., mRNA, protein) is still present. A measure of turnover time.
Plants that can grow in saline environments.
(Of a cell or plant) Containing the same set and number of chromosomes as the gametes of the species.
See proton pump.
Specialized feeding structure formed from a hypha of a biotrophic fungus or oomycete after penetration of a host-plant cell.
Inner, older region of a tree trunk in which water conduction has ceased and cells become filled with polymeric phenolic compounds, gums, etc.; as distinct from sapwood.
Protein molecular chaperones that buffer specific proteins against misfolding and stress (e.g., heat)-induced denaturation.
Porphyrin containing an iron atom; tightly bound cofactor in some classes of proteins involved in electron-transfer reactions.
Pathogen causing an infection in which host cells initially remain alive but then collapse and die as infection progresses.
Cell wall polysaccharides with glucose or xylose backbones and side chains rich in xylose or arabinose.
Plant species that can photosynthesize but relies on vascular connection to a host plant for water and minerals.
Plant with no persistent woody stems, often dying back in winter.
(Of an animal) Consuming plants as a food source.
Region of a chromosome with tightly packed chromatin and a low content of active genes; as distinct from euchromatin.
Greater strength, size, growth, or fitness of an F1 hybrid in relation to its pure-bred parents. Also called hybrid vigor.
Dependence on organic forms of carbon as food; as distinct from autotrophy.
Type of signaling pathway (e.g., in cytokinin signaling) in which receptor autophosphorylation triggers a sequence of phosphorylations of his then asp residues in downstream proteins, ultimately activating a transcription factor.
Chromosomal proteins around which DNA is wound to form nucleosomes.
Non-photosynthetic plant dependent on vascular connections to a host plant for carbon, water, and minerals.
Condition in which internal processes of a cell are in a stable, constant state.
Mutant plant in which one component, such as a floral whorl, is transformed into a different component (e.g., stamens transformed into carpels).
In allopolyploids, genes or chromosomes with similar sequences and a common ancestry, brought together through the combining of two or more genomes of related species.
Chromosomes, genes, nucleic acids, or proteins that have a common ancestry but have diverged over evolutionary time.
Recombination between homologous sequences located on non-sister chromatids at prophase I of meiosis.
(Of a cell, plant, or plant part) Having plastids or mitochondria with identical genetic material throughout.
In a diploid organism, having two identical alleles of a gene at a particular locus.
In bacteria and archaea, movement of genetic material between genetically distinct organisms.
Diverse plant signaling molecules that modulate plant growth, development, and responses to the environment, often through coordinated signal transduction pathways that integrate multiple inputs.
Cell or plant forming a mutualistic or pathogenic relationship with another organism.
See heterosis.
Crossing of two genetically distinct parent plants to produce (hybrid) progeny. See also cross-hybridization.
Specialized organs on leaf margins, particularly at the ends of principal veins, that may exude water and salts. See also guttation.
Efficiency of water flow through a system: flow rate at a given water potential difference across the system.
Branching of lateral roots in response to spatial patterns of water availability in the soil.
See turgor pressure.
Directional growth of plant roots toward regions of soil with an elevated water content.
Plant signaling molecule involved in systemic acquired resistance to pathogens.
An increase in the negative charge across a membrane above the value in a resting state.
R gene–mediated defense mechanism causing very localized death of plant cells upon pathogen invasion.
In fungi, long, often branched, sometimes multinucleate tube-like filaments that ramify through a substrate and may associate to form large fruiting bodies.
In symbiotic and pathogenic fungi, specialized hyphal structure formed on plant surfaces that facilitates infection.
Region of the stem of a eudicot embryo or seedling between the cotyledons and the radicle.
In a plant embryo, the cell layer beneath the epidermal layer.
At an oxygen concentration below ambient.
Uptake of water by seeds prior to germination.
In plastids and mitochondria, protein complexes in the outer and inner envelope membranes that mediate the import of proteins into the organelles (TOC and TIC in plastids, TOM and TIM in mitochondria).
Describes analyses, simulations, or modeling of a biological process employing computational rather than experimental methods.
Action on a gene of a protein, such as a transcription factor, located elsewhere in the genome.
See tissue culture.
Near-homozygous line of plants maintained by self-pollination. Also called pure-breeding line.
Random partitioning of different maternal and paternal chromosomes during meiosis due to their independent alignment at the spindle equator at metaphase I.
Growth producing a number of organs that is not genetically determined; as distinct from determinate.
Taking place or becoming active in response to defined signals or stimuli; as distinct from constitutive.
In nodule formation on roots, a plant-synthesized tube containing rhizobia that grows along a root hair cell and through the cortex to developing nodule cells, led by an organizing complex called an infectosome.
Flowering structure of a plant: depending on species, one to many stems that bear flowers.
Reproductive shoot apex that gives rise to floral meristems.
Equipment that monitors CO2 and water vapor concentration in air by measuring transmission of infrared radiation. Used to measure the rate of CO2 assimilation by plants.
Meristematic cell that divides continually to renew itself and to contribute a descendant that differentiates into a specific cell type.
Highly phosphorylated inositols, including inositol hexaphosphate (phytate) and Ins P8 that signals intracellular P levels.
In eudicots, the two layers of maternal cells that envelop the ovule, forming the seed coat.
Meristem at the base of a stem, stem section (node), or leaf; as distinct from apical meristem. Also called basal meristem.
Cultivation of two or more crops in the same field, often as alternating rows.
Region of chromosomal DNA between transcribable genes.
Segment of a stem between the insertion points of two successive leaves.
Part of the cell cycle in which the cell grows, DNA is replicated, and pre-division changes occur. Includes G1, S, and G2 phases.
Inner of the two cell walls of the pollen grain. See also exine.
Occurring within a structure rather than at its outer surface; as distinct from extrinsic.
Non-coding regions within the open reading frame of a gene. Introns are removed from RNA transcripts during RNA processing. See also RNA splicing, exon.
See outwardly rectifying channel.
Cluster of iron and sulfur atoms mediating electron transfer in some enzymes involved in oxidation–reduction reactions.
See flavonoids.
Proteins with the same function encoded by different genes, often with different regulatory properties and temporo-spatial distributions.
Five-carbon structural unit of terpenes.
(Of plant cell growth) Expansion equally in all directions.
Hormone involved in responses to environmental changes, pests and some developmental processes.
In the cell wall, structures formed by cross- linking of homogalacturonan polymers through calcium cross-bridges.
Protein activated by karrikins that promotes degradation of the SMAX1 inhibitor of the mycorrhizal symbiosis signaling pathway.
Antibiotic toxic to plants: blocks plastid and mitochondrial translation machinery. Used as a selectable marker in plant transformation.
Hormones involved in plant development, structurally similar to strigolactones. Also found in smoke, and responsible for post-fire germination in some species.
Stage of cell division in which replicated chromosomes are separated on a spindle.
Protein that severs microtubules during cytoskeletal rearrangements.
Unit of mass, equivalent to 1,000 daltons where a dalton is 1/12 of the mass of carbon-12.
Motor proteins that transport cargo molecules along microtubules, using energy from ATP hydrolysis.
Chromosomal attachment point for spindle microtubules during karyokinesis, located in the centromere.
Concentric arrangement of photosynthetic cells around the vascular bundles in the leaves of C4 plants.
Specialized, highly elongated cells that synthesize and store latex.
Early variants of domesticated crop species that were farmer-selected and specific to particular locations.
See LEA.
Sticky emulsion based on terpenoid and polysaccharide polymers, found in ~10% of land plants and involved in defense against pests.
Proteins that accumulate late in embryogenesis and in response to water deficit.
Groups of cells on the flanks of the shoot apical meristem that develop into leaves.
Strand of vascular tissue in the leaf that is connected to the vasculature of the stem.
The smaller units that make up a compound leaf.
Proteins that bind carbohydrates, especially sugar moieties of other molecules, potentially causing agglutination. May have roles in plant defense.
In leguminous plants, a heme-containing protein that binds O2 to maintain a low-oxygen environment in root nodules.
Multicellular pores in the surface of woody stems and trunks that provide aeration for internal tissues.
Molecule that binds to another molecule (e.g., a protein) to bring about a specific biochemical change.
See compensation point.
Thylakoid membrane complex of protein (light-harvesting complex polypeptide; LHCP) and chlorophyll molecules in the antenna of a photosystem.
Rigid polymer of phenylpropanoid monolignols, deposited in the walls of many plant cells; the main constituent of wood.
See genetic linkage.
In plant breeding, persistence of a linked undesirable trait through multiple rounds of selection for a desirable trait.
Membrane composed of two layers of amphipathic lipids, often phospholipids, with hydrophobic tails inside and polar heads on the outside.
In grasses, membranous floral organs adjacent to the stamens.
Plants induced to flower when the hours of daylight are greater than a critical length.
Non-coding RNA molecules usually larger than 200 bases that function in gene regulation.
Mutation in a gene that reduces or completely prevents the normal function of its product.
Firefly enzyme that causes light emission by catalyzing ATP-dependent decarboxylation of luciferin; LUC is used as a reporter gene in plants.
Internal spaces of membrane-bounded compartments, applied to e.g., the endomembrane and thylakoid systems.
Formation of spaces between cells by programmed death of intervening cells. See also schizogeny.
In the cell cycle, phase in which replicated chromosomes are separated to form two nuclei, followed by formation of daughter cells.
Nutrients essential for plant growth and required in relatively large amounts: N, P, K, Ca, Mg, S; as distinct from micronutrients.
Family of transcription factors with a conserved DNA-binding motif (MADS domain).
See mitogen-activated protein (MAP) kinases.
Selection of progeny with a desired trait using linked molecular or phenotypic markers.
Membrane protein that functions as a channel for specific molecules or ions in response to mechanical stimuli.
In seed plants, multicellular haploid structure that contains the egg cell.
The pascal (Pa) is the SI unit of pressure. Average pressure in the atmosphere is about 100 kPa.
Haploid product of meiosis that gives rise to the megagametophyte.
Diploid cell that undergoes meiosis to produce four haploid megaspores.
See mega- and microsporocyte.
In plant reproduction, the form of cell division giving rise to haploid spores that develop into male and female gametophytes.
See lipid bilayer.
Charge difference (usually given in mV) across a membrane, caused by a differential distribution of ions.
Patterns of inheritance of traits that reflect the segregation and independent assortment of alleles during meiosis in parent plants; as distinct from cytoplasmic inheritance.
Protodermal cell from which stomatal guard cells arise.
Tissues in specific regions of the plant consisting of undifferentiated stem cells, which give rise to the differentiated cells of all plant organs.
Fleshy part of a fruit, between the skin and the seed.
Photosynthetic cells of a C3 leaf; outer ring of chloroplast-containing cells in a C4 leaf. See also spongy mesophyll, palisade mesophyll.
RNA molecule transcribed from DNA, processed, then translated into a protein sequence on ribosomes.
Mechanisms that exchange metabolites in different oxidation states across organellar membranes, balancing generation and consumption of reducing power in the two compartments separated by the membrane.
Stage of mitosis (cell division) and meiosis in which condensed chromosomes align in the center of the cell.
Community of microorganisms occupying a defined location, e.g., soil, rhizosphere, phylloplane.
In seed plants, haploid gametophyte (pollen grain) that gives rise to the sperm.
Nutrients essential for plant growth that are required in relatively small amounts; as distinct from macronutrients.
In a seed, region of the endosperm adjacent to the micropyle through which the radicle emerges upon germination.
In seed plants, opening through which the pollen tube enters the ovule.
Small RNAs (usually 21–26 nucleotides) that participate in post-transcriptional control of gene expression.
Compartment in a developing anther in which pollen grains form. See also microsporocyte.
Haploid cells formed by meiosis in a microsporocyte, which then develop into pollen grains.
Diploid cell in a microsporangium that undergoes meiosis to produce four haploid microspores. Also called pollen mother cell. See also microspores.
Filamentous, hollow tubes composed of polymers of the protein tubulin; components of the cytoskeleton and the spindle.
Layer of pectin between the walls of adjoining cells.
The DNA in mitochondria; as distinct from nuclear genome; plastid genome.
Organelle with a double membrane containing the enzymes and electron transport chain that generate ATP from oxidation of pyruvate to CO2 in oxygen-dependent respiration. See also oxidative phosphorylation.
Protein kinases involved in signaling pathways. In MAP kinase cascades, an external stimulus typically leads indirectly to phosphorylation of MAP kinase kinase kinase (MAPKKK), leading to successive phosphorylations of MAPKK then MAP kinase, which phosphorylates and thus activates target proteins.
Process in which chromosomes are duplicated and separated into two daughter cells.
See transposon.
Means of estimating the time of divergence of two species from a common ancestor, using differences in DNA sequence.
Molybdenum- and sulfur-containing cofactor required by some enzymes that catalyze oxidation–reduction reactions.
Plants that die following maturation of their seeds.
Having a single opening; monocolpate pollen has a single opening through which the pollen tube emerges.
One of two main groups of angiosperms, usually with a single cotyledon or seed leaf, parallel leaf venation, floral organs in multiples of three; as distinct from eudicots, eudicotyledons.
A crop consisting of genetically uniform individuals of a single species.
Phenolic compounds that polymerize to form lignin; primarily coumaryl, coniferyl, and sinapyl alcohols.
A group of organisms derived from a single ancestor; as distinct from polyphyletic group.
See open reading frame.
Development of morphological characteristics, involving the coordination of cell division, growth, and differentiation.
See DNA sequence motif, amino acid motif.
Proteins that move cargoes along microtubules or actin filaments, involved in e.g., chromosome separation on the spindle during mitosis and meiosis, phragmoplast assembly and function, tip growth. See also kinesins, myosin.
Proteins encoded by plant viruses that allow movement from an infected cell to adjacent cells via plasmodesmata.
Similar but non-identical genes within a genome that have arisen by duplication: they may be clustered on a chromosome or dispersed through the genome.
Treatment, often with chemicals or radiation, of a plant or plant organ that brings about mutations in the genome.
Individual with specific, heritable change(s) in its DNA sequence; as distinct from wild type.
Heritable change in the DNA sequence of a gene.
Close association between two different organisms. See also symbiosis.
Family of transcription factors with a conserved DNA-binding domain (MYB domain).
Symbiotic associations between a plant and a fungus, usually involving root colonization by the fungus and formation of a novel symbiotic structure. See also ectomycorrhizae, endomycorrhizae.
Compounds produced by fungi that are toxic to mammals or other organisms.
Motor protein that transports cargo molecules along actin filaments, using energy from ATP hydrolysis. See also motor proteins.
Oxidized and reduced forms of nicotinamide adenine dinucleotide, a coenzyme that acts as an electron carrier in many biochemical oxidation–reduction reactions.
Oxidized and reduced forms of nicotinamide adenine dinucleotide phosphate, a coenzyme that acts as an electron carrier in many biochemical oxidation–reduction reactions. NADPH is a product of the light reactions of photosynthesis.
Plasma membrane-bound enzyme complex that catalyzes transfer of an electron from NADPH inside the cell to molecular O2 outside the cell, producing superoxide. Also called RBOH.
Process whereby alleles conferring enhanced reproductive success on individuals in a population increase in abundance in the population over time. See also selective pressure.
Genetic differences that have accumulated naturally within populations of a single species.
Establishment of a non-native species of plant as a component of the flora in a new region or country.
Two lines of a plant species that are genetically identical (isogenic) apart from very small regions of the genome. Near-isogenic lines are created in recurrent back-crossing programs.
Pathogenic organism that causes the death of host tissues as it invades the cells, such that it always colonizes a dead substrate.
Liquid with a high concentration of sugars (sucrose, glucose, and fructose) secreted by many flowers as an attractant to pollinators.
Generally small, ubiquitous cylindrical worms of the phylum Nematoda, some of which are plant pathogens.
Protein degradation system in which modification of the N-terminus of a short-lived protein targets it for degradation. In plants, a low-O2 sensor protein is targeted for N-end rule degradation at normal O2 concentrations by oxidation of its N-terminal amino acid.
Divergence in function of two genes following their formation by duplication.
Imposition of a short period of illumination during the normal period of darkness, for experimental purposes.
Conversion by soil bacteria of ammonia to nitrite and then nitrate.
In plants, the process by which inorganic forms of nitrogen, such as nitrate and ammonia, are combined into organic molecules, such as amino acids.
In certain bacteria, the conversion of gaseous nitrogen (N2) to ammonia (NH3).
Bacteria that can convert nitrogen gas to ammonia.
The enzyme complex that catalyzes conversion of gaseous nitrogen (N2) to ammonia (NH3) in bacteria. Contains dinitrogenase and dinitrogenase reductase components.
(Nucleotide-binding domain leucine-rich repeat genes/proteins) Intracellular immune receptor proteins that function in plant disease resistance.
Signaling molecules produced by rhizobia that initiate nodule formation on the roots of host legumes.
See root nodules.
Protein that can move from the cell in which it was synthesized into adjacent cells.
Processes leading to the dissipation of excess energy in excited chlorophyll, as heat or fluorescence.
Targeted degradation of a defective mRNA that cannot be translated.
Replicated chromatids of pairs of homologous chromosomes.
In plant reproduction, diploid tissue surrounding a megagametophyte.
Double membrane surrounding the cell nucleus; part of the endomembrane system.
All of the DNA in the chromosomes of the nucleus; as distinct from mitochondrial genome; plastid genome.
Large protein complex that forms a pore in the nuclear envelope allowing the passage of proteins and nucleic acids.
Genes encoding proteins that suppress the male-sterility phenotype conferred by some mitochondrial mutations.
Regions of the nucleoplasm containing spliceosomes responsible for RNA transcript splicing and maturation.
RNA polymerase encoded in nuclear DNA and imported into plastids.
Chromosomal region containing many copies of the genes for ribosomal RNA, around which the nucleolus forms.
Site of ribosomal RNA processing and ribosome assembly in the nucleus.
Matrix surrounding the chromosomes and nucleoli in the interphase nucleus.
Repeating subunit of chromatin, consisting of DNA wrapped around a core of eight histone proteins.
Membrane-bounded organelle that contains the chromosome complement of the cell.
(Of an organism) Restricted to, or dependent on, particular conditions or processes; as distinct from facultative.
Organelles containing storage lipid (triacylglycerols), surrounded by a layer of the protein oleosin.
Protein with hydrophobic and hydrophilic domains that forms a monolayer around oil bodies.
Association of two or more proteins to form a multimeric complex.
See fatty acids.
Member of the Oomycota, eukaryotic microorganisms resembling fungi but more closely related to brown algae (Phaeophyceae).
Region of a gene and its RNA transcript containing a sequence encoding a protein. mORF, main open reading frame. uORF, upstream open reading frame, often with a regulatory function.
In prokaryotic and organellar DNA, sequence transcribed as a single mRNA that typically encodes a regulator and several other proteins.
Amino acid-derived compounds synthesized in Agrobacterium-infected tissues by T-DNA encoded enzymes, using host substrates.
Membrane-bounded components of eukaryotic cells; for example, plastids, mitochondria, and peroxisomes.
Group of cells below the central zone of the shoot apical meristem involved in maintenance of the meristem stem cell population.
Genes inherited from a common ancestor that perform similar functions in different species.
Osmotically active compounds important in osmoprotection and maintenance of osmotic homeostasis; also called compatible solutes.
Protection of cellular structures and macromolecules against osmotic stress caused by e.g., high salt or drought conditions.
Movement of water through a selectively permeable membrane from a region of high water potential (low solute concentration) to a region of lower water potential (higher solute concentration).
Measure of the tendency of water to move through a selectively permeable membrane from low-solute to high-solute regions.
Plant species unable to self-pollinate. Pollination requires pollen from a genetically different plant.
Channels that allow the movement of K+ out of or into the cell in response to reductions in the plasma membrane potential.
In flowers, structure containing the ovules and bearing the pistil.
In angiosperms, the female gametophyte together with its protective integuments.
An increase in the oxidation state of a molecule, brought about by loss of one or more electrons, loss of hydrogen, or addition of oxygen.
Process by which fatty acids are broken down to yield acetyl-CoA.
Reversible reactions in which substrates undergo oxidation or reduction.
Ubiquitous metabolic pathway linked to glycolysis that generates NADPH and four- and five-carbon sugars as precursors for biosynthesis.
Synthesis of ATP in mitochondria, using reducing power generated by oxidation of sugars to CO2. See also ATP synthases, photophosphorylation.
In a C3 leaf, elongated mesophyll cells below the upper (adaxial) surface.
Microbial molecules (e.g., flagellin, chitin) recognized by plants as cues to activate defense mechanisms.
Genome sequencing of large numbers of individuals of the same species to reveal natural genetic variation.
Branched inflorescence with flowers borne on pedicels.
Homologous genes that have diverged in sequence after gene duplication in a single species.
Insect that parasitizes another insect species. Eggs are laid on host larvae, which are eaten by the parasitoid larvae when the eggs hatch.
Tissues of relatively undifferentiated cells found in most plant organs. See also ground tissue.
Experimental means of delivering DNA to a plant cell nucleus or plastid. DNA-coated gold particles are bombarded into tissues at high velocity.
Movement of molecules or ions across a membrane down a concentration and/or electrical gradient, without an energy requirement; as distinct from active transport.
Proteins, usually secreted, that increase greatly in abundance after pathogen challenge and in systemic acquired resistance.
Organisms that cause disease in other (host) species.
Genetic variants of a pathogen.
Class of plant extracellular receptors that recognizes conserved components in a range of plant pathogens and triggers defense responses.
Plant defense response triggered specifically by PRR recognition of PAMPs.
Leaf epidermal cells with jigsaw-like interlocking shapes.
Linear and branched polysaccharides containing galacturonic acid and several other sugars that form the gel-like matrix of the plant cell wall.
Stalk bearing a single flower in an inflorescence.
Structure emerging from the appressorium of some pathogenic fungi that penetrates the plant epidermal cell wall.
Nuclear-encoded plastidial RNA binding proteins that mediate RNA maturation and editing.
Cross-linked polymers of sugars and amino acids that form the walls (outside the plasma membrane) of bacteria.
Plants that live for more than two years, usually flowering annually.
In xylem, walls at the ends of individual vessels that have large openings or perforations.
Outermost whorls of a eudicot flower; usually petals and sepals.
Plant-derived membrane surrounding nitrogen-fixing bacteroids in rhizobial nodules on the roots of legumes.
In plant reproduction, maternally derived wall surrounding the ovary; the fleshy part of many fruits.
In a direction parallel to a nearby surface; as distinct from anticlinal.
In roots, outermost cell layer of the stele, inside the endodermis.
Outer cork or bark layer of a woody stem. See also phellogen.
Region flanking the central zone of the shoot apical meristem; zone in which organ primordia are initiated.
Organelle containing catalase and other oxidative enzymes; site of reactions in the photorespiratory cycle in leaves.
Insects, mites, nematodes, and other animals that attack plants.
One of the whorls of a eudicot flower, often with features (color, shape, texture) that facilitate flower pollination.
Stalk that attaches a leaf blade to the stem.
In a cell matrix, spontaneous condensation of specific macromolecules (proteins, or nucleic acids) into separate bodies.
In woody stems, a meristem in the periderm that generates cork or bark on the outside of the stem.
Compounds with a phenyl group derived from phenylalanine or tyrosine, with many diverse functions in plant cells.
Component of the vascular system that transports sucrose and other molecules from leaves to the sink organs of the plant.
Process in which sucrose synthesized in leaf mesophyll cells moves into the phloem for export from the leaf.
Cells other than sieve elements and companion cells that are associated with the phloem in plant vasculature.
Induction by low soil phosphate of expression of genes encoding proteins that influence phosphate requirements and availability in the cell.
Class of translocator (transporter) that moves phosphorylated metabolites across membranes in exchange for inorganic phosphate.
Class of glycerolipids abundant in membranes, in which position 3 of the glycerol backbone has a phosphate group that may be linked to other compounds including choline, ethanolamine, or serine.
Excitation (energization) of chlorophyll molecules by light.
Damage to components of the light reactions of photosynthesis when exposed to excess light.
Response of plant development to light; process of seedling development in the light.
Elementary particle of electromagnetic radiation.
Length of the light period during a day-night cycle.
Plant responses (e.g., induction of flowering) to photoperiod length.
Synthesis of ATP in chloroplasts during photosynthesis. See also ATP synthases.
Light-sensitive protein, usually with a chromophore, that initiates signaling when activated by light of a specific wavelength.
Loss of CO2 from leaves in the light due to operation of the photorespiratory cycle.
Pathway converting the 2-phosphoglycolate product of Rubisco oxygenase activity to 3-phosphoglycerate and CO2.
Process by which light energy absorbed by chlorophyll is converted to chemical energy that drives assimilation of carbon from CO2 into organic molecules.
Large protein–chlorophyll complexes in thylakoid membranes, connected by an electron transport chain and acting in series, that capture light energy and convert it to chemical energy for carbon assimilation in photosynthesis.
Blue-light photoreceptors that mediate phototropic and other blue light responses.
Directional growth toward (positive phototropism) or away from (negative phototropism) a light source.
Structure formed at the site of the spindle equator at the end of mitosis in which the new primary cell wall grows; see also cell plate.
Surfaces of above-ground plant parts, particularly leaves, that support communities of microorganisms.
Relative positions of leaves around a stem.
Level of classification of organisms immediately below Kingdom.
Analysis of multiple genome sequences to reconstruct the evolutionary history of a species or group of species.
Evolutionary history of one or several species, often depicted as a phylogenetic tree showing relationships to other species.
Inositol hexaphosphates, the main form of phosphate storage in many plant tissues including seeds.
Defense compounds produced by plants in response to attack by pathogens.
Photoreceptor protein, sensitive to light in the red and far-red regions of the spectrum.
Transcription factors that together repress expression of genes for photomorphogenesis and activate expression of genes for skotomorphogenesis.
Basic shoot module of a plant, consisting of a leaf attached at a node, an axillary bud or meristem, and an internode.
Microscopic photosynthetic organisms in the upper layers of lakes and oceans, responsible for almost half of global photosynthesis.
Compounds secreted by roots that chelate iron in the soil, facilitating its uptake.
See phytochrome interacting factors.
Compounds that absorb specific wavelengths of light and reflect other wavelengths within the visible part of the spectrum: the reflected wavelengths give plants their colors.
Proteinaceous tube through which genetic material is exchanged between bacteria, and effector proteins are secreted into host organisms.
Plasma membrane transporter in plants that exports auxin from the cytosol to the apoplast.
In plant reproduction, inner tissue of a carpel that gives rise to ovules.
A fraction of bacteria in the rhizosphere that specifically promotes plant growth.
Semi-permeable membrane surrounding the cell, enclosing the symplast.
Circular DNA in bacteria that replicates independently of chromosomal replication and can be transferred between bacteria by conjugation.
Plasma-membrane lined channel through the wall between adjacent cells, providing symplastic continuity. See also cytoplasmic sleeve, desmotubule.
Shrinkage of the cell protoplast due to water deficit, causing the plasma membrane to separate from the cell wall.
DNA contained in the plastid; as distinct from mitochondrial genome, nuclear genome.
Multisubunit, plastid genome-encoded RNA polymerase, regulated by nuclear-encoded sigma factors.
Plant organelles including chloroplasts, amyloplasts, and chromoplasts, bounded by a double membrane and containing a small genome.
In proteins, flat surface created by H-bonding between two or more parallel or anti-parallel amino acid chains (β-strands).
Influence exercised by a single gene on multiple phenotypic traits.
A “breathing root” of swamp trees (e.g., mangroves), which grows up into the air and conducts oxygen to the root system.
Grasses and grass-like species including wheat, sorghum, maize (corn), bamboo. It is the most economically important plant family.
Directional movement of auxin through a cell or tissue, brought about polar location of PINs at specific sides of cells.
In plants, regions at the poles of mitotic spindles toward which chromatids are partitioned during anaphase in mitosis and meiosis.
Asymmetric organization of structure or function of a cell or tissue, distributed along a defined axis. See also apical–basal polarity.
Male gametophyte of seed plants. In angiosperms, it contains two sperm cells and a vegetative cell that will form the pollen tube.
See microsporocyte.
Extension of the male gametophyte that emerges from the germinating pollen grain and delivers the sperm nuclei to the ovule.
In angiosperms, the transfer of pollen from an anther to a stigma of the same (self-pollination) or another (cross-pollination) flower.
Organism (often an insect or bird) that transfers pollen from one flower to another.
20–80 adenosine nucleotides added post-transcriptionally at the 3´ end of all eukaryotic mRNAs.
Transcript that contains more than one protein-coding sequence.
Complex with a general role in introducing H3K27me histone modifications that repress gene expression.
Long linear hydrocarbons of alternating ketone and methylene groups: [-C(=O)-CH2-]n.
In genetics, the existence of a gene in two or more allelic forms in a population.
Group of organisms derived from multiple unrelated ancestors; as distinct from monophyletic group.
Having more than two complete sets of homologous chromosomes.
Large protein encoded by a single mRNA that is cleaved after synthesis into multiple proteins with distinct functions.
Polymers of sugar residues; for example, starch, pectin, and cellulose.
See tetrapyrrole.
Process of defining a gene location on a chromosome using molecular markers and analysis of recombinant progeny.
See RNA interference.
Modulation of protein (enzyme) function by covalent modification or non-covalent interactions with specific ligands.
Disease caused by the hemibiotrophic oomycete Phytophthora infestans.
Proteins present in large amounts as aggregates or filaments in the sieve elements of phloem.
Dense ring of microtubules that forms prior to mitosis beneath the plasma membrane at the future plane of cell division.
Movement of sugars through phloem sieve tubes driven by the difference in pressure between source and sink ends of the phloem.
See turgor pressure.
Processes that generate carbon skeletons, reducing power, and energy from imported sucrose in a non-photosynthetic cell.
Conversion of energy from a physical to a chemical state in a photosystem reaction center.
Growth arising directly from the activities of the shoot and root apical meristems.
Engulfing by an ancestral non-photosynthetic eukaryotic cell of a cyanobacterium-like photosynthetic prokaryote, which evolved into a chloroplast.
Metabolic processes occurring in all plant cells and essential to the life of the plant.
miRNA precursor with self-complementary sequences that form hairpins: regions of double-stranded RNA (dsRNA).
Induction of expression of genes involved in N uptake and assimilation following nitrate supply to N-deficient roots.
Uptake and assimilation of inorganic nitrogen, as nitrate or ammonia, from the soil. See also nitrogen assimilation.
The first root to develop in the seedling, arising from the root apical meristem of the embryo.
In woody monocots, meristem immediately below the apical meristem and leaf primordia that generates the trunk. In many monocots, no further thickening occurs below this meristem. See also secondary thickening meristem.
Short RNA molecules that hybridize to larger DNA or RNA molecules as the starting point for their replication.
In plants, groups of cells on the flanks of a meristem that will develop into a new organ.
Ubiquitous protein that regulates actin turnover in the cytoskeleton. Abundant in pollen, and a major cause of hay fever.
Type of cell death that involves a series of genetically programmed steps.
Organisms in the domains Bacteria and Archaea with genetic material in the cytoplasm, not in a nucleus; as distinct from eukaryotes.
Class of storage proteins typically found in cereal seeds.
A DNA sequence from which gene transcription is initiated by the binding of regulatory proteins and RNA polymerase.
Any structure that can give rise to a new plant; for example, a seed or a part of the vegetative body of the plant.
First stage of mitosis, during which the chromosomes condense but are not yet attached to a mitotic spindle; also a stage of meiosis.
An undifferentiated plastid, not specialized for a specific metabolic function.
Enzymes that cleave the peptide bonds between amino acid residues of peptides and proteins.
Multisubunit enzyme complex that degrades proteins that are specifically tagged for destruction, often following polyubiquitination on an E3 ubiquitin ligase.
Organelles packed with storage proteins, found in the cells of storage organs.
Region of a protein with a stable, defined structure conserved in a particular group or family of proteins, often with a conserved biological function.
See translocation apparatus.
Cleavage of the peptide bonds between amino acid residues of proteins by proteases.
In a plant embryo, the outer cell layer that gives rise to the epidermis; also the outer cell layer (L1) in early leaf development.
A hypothetical ancestral cell with genetic material contained in a nucleus but lacking plastids and mitochondria.
Electrochemical gradient across the inner membrane of the chloroplast or mitochondrial envelope, set up by electron transport-driven proton transfer across the membrane and potentially capable of driving ATP synthesis.
Membrane protein that drives movement of protons across a membrane using energy from ATP hydrolysis. Also called H+-ATPase.
Contents of a plant cell bounded by the plasma membrane; a plant cell without its cell wall.
In plants, the earliest morphologically identifiable stage of a developing vascular strand.
A line through an organ from its site of attachment to the plant body to its furthest tip.
Means of assessing photosynthetic efficiency by measuring leaf fluorescence emission during repeated light flashes.
Genetically isogenic or near-isogenic individuals that produce offspring with characteristics identical to their parents.
Rubisco-containing phase-separated compartment in algal and hornwort chloroplasts, essential for the carbon-concentrating mechanism that underpins photosynthesis in these species.
Factor by which the rate of a biochemical reaction or set of reactions changes in response to a 10°C rise in temperature.
Phenotype with a few discrete forms, exhibiting discontinuous variation.
Phenotype exhibiting continuous variation.
A region of DNA preferentially inherited in association with a particular quantitative trait (e.g., high crop yield); a region genetically linked to a locus that contributes to the trait.
Central region of the root meristem that has little or no mitotic activity.
In bacteria, sensing of population density that determines when genes for particular processes are induced.
In plants, genes that exhibit variation and Mendelian segregation for the capacity to confer host resistance to specific races of certain pathogens. Most encode intracellular immune receptors (NLR proteins). See also effector-triggered immunity.
Main axis of a compound leaf, or of an inflorescence (spike) of e.g., wheat and other cereals.
Embryonic root.
In wood, elongated cells in radial files (rays), perpendicular to the annual rings. See also ray initials.
In wood, cells in the vascular cambium from which ray cells arise.
Genes encoding small subunits of Rubisco.
See NADPH oxidase.
In photosynthesis, part of the core complex of a photosystem in which the primary charge-separation event converts light energy to chemical energy.
All forms of nitrogen except N2.
Molecular species including superoxide, hydrogen peroxide, and the hydroxyl radical.
Thickened upper part of the flower pedicel that forms part of the fruit in some species.
Intracellular protein kinases involved in signal transduction that phosphorylate downstream regulators following their own phosphorylation by activated RLKs.
Plasma membrane proteins with external sensor and internal kinase domains: the predominant sensors of extracellular signals in plants.
Molecules (usually proteins) that perceive other specific molecules or wavelengths of radiation, leading to conformational changes that trigger cellular responses.
Crossing strategy in which the parental lines are used as both male and female parents.
Chromosome resulting from meiotic recombination of non-sister chromatids of homologous chromosomes; containing segments of genetic material from both parents.
In meiosis, the process by which non-sister chromatids of homologous chromosomes, paired during prophase I, undergo reciprocal exchange of chromosomal segments.
In meiosis, the complex that breaks and rejoins the two DNA strands of non-sister chromatids to bring about reciprocal exchange (crossing over) of chromosomal segments.
Frequency of crossing over between two genes on a chromosome.
In plant breeding, repeated sequential backcrossing of a line carrying a desirable trait to an elite recipient parent.
Availability of reduced cofactors (such as NADH, NADPH) that can donate electrons in biosynthetic and other metabolic processes.
Decrease in oxidation state brought about by gain of electron(s), addition of hydrogen, or loss of oxygen.
Tendency of a molecule to gain electrons; likelihood that a given molecule will be reduced.
Enzyme activation by reduction of a disulfide bond between two specific cysteine residues to form sulfhydryl groups.
The process by which a DNA sequence is copied to form two or more new copies.
Central tissue of the style through which pollen tube grows during fertilization.
Genes introduced into plants to facilitate monitoring of the location and/or dynamics of a protein or process. Reporter genes often encode fluorescent or luminescent proteins. See also green fluorescent protein, luciferase.
Oligomeric structures formed by NLR proteins following detection of pathogen effectors in plant cells: they trigger Ca2+-mediated defense responses by acting as membrane Ca2+ channels.
Metabolic process that generates ATP through oxidation of hexoses to CO2, involving conversion of oxygen to water.
Rapid production of reactive oxygen species (ROS) accompanying induction of pattern-triggered immunity by a pathogen in a plant host.
See NADPH oxidase.
Small number of species able to recover from near-complete dehydration (loss of >95% of water content) when rehydrated.
Netted (reticulate) patterns formed by the veins in the leaf of a eudicot.
Nuclear phosphoprotein that normally acts as an inhibitor of cell proliferation and the cell cycle.
Signaling or transport directed back toward the original source of a stimulus or transportable cargo; as distinct from anterograde signaling, transport.
A sequence of DNA that can be inserted into a new location in the genome by a process that involves an RNA intermediate.
Discovery of the function of an identified gene by characterizing mutant or transgenic plants in which its expression has been specifically eliminated or increased.
Enzyme that converts an RNA template (from transcription of e.g., viral or transposon DNA) into complementary DNA (cDNA).
Conversion of a transposon-mutated gene back to the wild-type gene by excision of the transposon.
Soil bacteria that induce roots of some plants (mainly legumes) to form nodules in which, in the form of bacteroids, they carry out symbiotic nitrogen fixation.
Rootlike structure in algae, mosses, lycophytes, and fern gametophytes, with nutrient-uptake and/or anchorage functions.
Underground stems that can send out shoots and roots or rootlets from their nodes.
Zone of influence of a plant root in the surrounding soil (due to e.g., exudates, protons, hormones, shed cells, and oxygen from roots).
Agrobacterium rhizogenes plasmid required for root infection: carries the T-DNA transferred into host cells.
Region of the shoot meristem that generates the internal tissues of the stem.
Type of RNA molecule with a structural role in ribosomes.
Cellular structures consisting of RNA and protein; the sites of protein synthesis.
In plastids and mitochondria, post-transcriptional conversion of specific cytosines in RNA transcripts to uracil, thus changing activity or abundance of the encoded proteins.
The RdDM complex associates with RISC to bring about DNA methylation, as part of mechanisms that maintain heterochromatin and suppress retrotransposon activity.
Complex containing an ARGONAUTE protein that binds small interfering RNAs that define targets for gene silencing: RISC is involved in various aspects of silencing of endogenous and foreign genes and DNA sequences.
Process initiated by a double-stranded RNA that leads to degradation of complementary mRNAs.
Enzymes that catalyze the polymerization of ribonucleotides to produce RNAs from a DNA template.
Modification of an RNA transcript to produce the functional, mature RNA; e.g., by removal of introns and polyadenylation. See also poly(A) tail, RNA splicing.
Removal of introns from an mRNA transcript during maturation, carried out by a nuclear spliceosome. See also alternative splicing.
RNA copy of a DNA template made by RNA polymerase; the transcript may be modified to form a mature RNA.
Enzyme that catalyzes the synthesis of RNA using another RNA as the template.
See apical meristem.
Tissue that covers the root apical meristem and is continuously shed and replaced during root growth.
Specialized cell of the epidermis in the root differentiation zone: a long, tubular outgrowth that extends by tip growth.
Nodular growths on the root system of some plant species (mainly legumes) that contain symbiotic nitrogen-fixing rhizobia in the form of bacteroids.
Positive pressure in root xylem vessels that occurs in the dark, and in the light when transpiration is low and water is plentiful.
Roots and lower stem of a plant onto which the shoot of another plant can be grafted. See also scion.
See endoplasmic reticulum.
Ribulose 1,5-bisphosphate carboxylase/oxygenase. Enzyme that catalyzes the initial step in the Calvin–Benson cycle; the assimilation of CO2 into organic compounds.
In the cell cycle, phase in which DNA synthesis occurs.
Signaling molecule involved in several cellular processes including establishment of systemic acquired resistance following a hypersensitive response to a pathogen.
In some halophytes, cellular projections from the leaf epidermis that terminate in large, salt-accumulating bladder cells.
Multicellular structures embedded in leaves of some halophytes in which salt is concentrated and secreted to the leaf surface.
Organism that feeds on decaying organic material.
In trees, most recently formed outer wood located inside the vascular cambium of the trunk, active in the conduction of water; as distinct from heartwood.
See fatty acids.
Formation of spaces between cells by splitting apart of existing files of cells. See also lysigeny.
Plant shoot that is grafted onto the root stock of another plant.
See fiber cells.
In grass seeds, cotyledon-like region of the embryo adjacent to the endosperm.
Components of a signaling pathway downstream of signal perception that multiply and propagate the original signal.
Plant cell wall with secondary thickening provided by lignin deposition; no longer able to expand.
Plant development from cambium or other secondary meristems, e.g., development of wood and bark. See also primary development, primary growth.
In evolution, events in which early plastid-containing eukaryotes became endosymbionts in other eukaryotes that lacked plastids, giving rise to new photosynthetic lineages (e.g., brown algae).
Metabolic processes deemed non-essential for basic cell growth; biosynthesis of many compounds necessary for protection against abiotic and biotic stress; as distinct from primary metabolism.
In some woody monocots, a flanking meristem derived from the primary thickening meristem that extends down the trunk and produces secondary growth along its length.
(1) Seeds in the soil that can germinate when conditions are favorable; (2) Another name for a germplasm collection.
See integuments, testa.
Seed-producing plant species (angiosperms and gymnosperms), spermatophytes.
See chromosome segregation.
In plant transformation, gene introduced with the gene of interest that protects against a toxin (e.g., antibiotic, herbicide): subsequent application of the toxin kills untransformed material and thus selects for material carrying the gene of interest.
Environmental factors that result in altered frequency of genes in a population, acting through changes in the relative reproductive success of individuals with a particular characteristic (trait).
Fertilization of ovules in a flower by pollen from the same flower.
Inability of pollen to fertilize ovules of the same flower. In gametophytic self-incompatibility, SI proteins are carried in the pollen; in sporophytic self-incompatibility, SI proteins are secreted onto the pollen by the parental tapetum. See also SI proteins.
Semi or incompletely dominant alleles that exhibit different phenotypes depending on their dosage. Heterozygotes exhibit a phenotype intermediate between those of homozygotes.
Genetically programmed death of a plant organ, accompanied by regulated breakdown of cells and recovery of nutrients.
Outermost floral organs of eudicots that envelop the developing bud.
Reproduction by fusion of male and female haploid gametes to form a zygote.
Growth response to low light conditions that may involve stem elongation and bending toward a light source.
Detaching or shedding of mature seeds or fruits from the parent plant.
Metabolic pathway producing amino acids with an aromatic ring (phenylalanine, tyrosine, tryptophan).
See apical meristem.
Plants that flower when exposed to periods of daylight shorter than a critical length.
Elongated, sucrose-transporting cells of the phloem.
Perforated end walls of sieve elements that connect the lumens of sieve elements and allow free movement of molecules through the phloem.
N-terminal peptide of a nascent protein recognized by the SRP for transfer to the ER.
Ribonucleoprotein that binds the N-terminal signal peptides of proteins to be transferred to the ER.
Sequence of downstream events triggered by binding or perception of a signal by a specific receptor, initiating events that often terminate in activation of gene expression.
Protein complex required to repress photomorphogenesis in the dark. Participates in the destruction of photomorphogenesis-promoting transcription factors.
Pod-like fruit of Arabidopsis and other members of the Brassicaceae.
Organs to which photosynthetic products are transported; as distinct from source organs.
Rate of consumption of photosynthetic products by a sink organ, which determines the fraction of total photoassimilate it receives.
Self-incompatibility proteins on the pollen and stigma that permit pollination by a plant with different SI alleles but prevent self-pollination.
Identical copies of a chromosome, formed by DNA replication.
Two species that are each other’s closest extant relative.
The upper size limit for molecules able to move between cells through plasmodesmata.
Response of plant development to darkness; process of seedling development in darkness.
Short RNA sequences (20–24 bases) involved in post-transcriptional gene regulation through RNAi.
Component of small nuclear ribonucleoprotein (snRNP) complexes that form spliceosomes.
Short, non-coding RNAs that regulate gene expression. See also microRNAs, small interfering RNAs.
See endoplasmic reticulum.
Conserved family of proteins important in membrane and protein trafficking, also vesicle formation, fusion, and docking.
Protein kinases with central regulatory roles in the plant. SnRK1 represses growth when sugar level (energy status) is low; SnRK2 controls responses to water deficit and other environmental stresses.
Pathway facilitating a continuous flow of water from the soil, through roots, stems into leaves, then into the atmosphere as water vapor via stomatal pores.
Describing the non-reproductive cells of a plant.
Photosynthetic organs that are the sources of assimilated carbon for other, non-photosynthetic organs of the plant; as distinct from sink organs.
A thick, fleshy spike that forms part of the inflorescence of the Araceae (arums).
In evolution, the process by which two populations of a species become reproductively isolated and diverge into separate species.
Male gamete, haploid reproductive cell.
See seed plants.
Components of the spike of some cereals, arising from the central rachis and bearing one to several grains, each subtended by a pedicel.
Array of microtubules formed between opposite poles of a cell prior to division; responsible for separation of replicated chromosomes.
Conserved sequences at the 5’ end (donor) and 3’ end (acceptor) of intron sequences targeted by spliceosomes during mRNA splicing.
Different mRNAs produced from a single gene due to alternative splicing. See also alternative splicing.
Nucleoprotein particle responsible for the splicing step of messenger RNA maturation in which introns are eliminated.
In a C3 leaf, loosely arranged, rounded mesophyll cells between the palisade cells and the lower epidermis.
Reproductive structure of plants, fungi, and oomycetes in which spores develop. See also microsporangium.
Reproductive, haploid cells that develop directly into a new individual, the gametophyte.
Diploid stage of the plant life cycle that produces haploid spores by meiosis.
Mechanism of self-incompatibility in which the pollen-associated SI proteins are products of maternal sporophyte. See also self-incompatibility.
Water-resistant, decay-resistant major component of the outer walls of pollen.
Male, pollen-producing organs of the flower.
Glucan composed of amylose and amylopectin organized into semi-crystalline insoluble granules, synthesized in plastids.
The first codon of an mRNA that is translated on a ribosome. In plants, it is AUG, encoding methionine.
Gene expressed in conditions of low carbohydrate availability hence potentially restricted growth.
Starch-filled plastids that function in gravity perception. See also amyloplasts, gravitropism.
The central vascular cylinder of roots, inside the endodermis.
Cells that divide to maintain a population of their own type and to produce initial cells, which divide to form specialized tissues; e.g., meristematic cells at the shoot and root apex.
Region of the carpel on which pollen grains attach and germinate.
Roots emerging from above the base of a stem or trunk that are anchored into the substrate and act as props for the plant.
Relating to the quantitative relationship between the amounts of substrates and the amounts of products in a biochemical reaction.
Horizontal stems at or below the ground surface, typically giving rise to tubers or clonal plantlets at their tips.
Pores flanked by guard cells on leaf surfaces that open or close according to external and internal conditions to allow passage of CO2 and water vapor between the atmosphere and the interior of the leaf.
A codon (UAA, UGA, or UAG) in mRNA that does not specify an amino acid and causes termination of translation on a ribosome.
Vegetative or reproductive organ that accumulates storage products (lipids, proteins, starch, etc.) when substrates are abundant.
Specific proteins accumulated in vegetative and reproductive storage organs that provide substrates for later plant regrowth or germination.
Hormones involved in many developmental processes and in the establishment of mycorrhizal symbioses.
Contents of a chloroplast outside the thylakoid membranes.
Protein complex that removes transit peptides from nuclear-encoded proteins imported into plastids.
Thylakoid membranes in the chloroplast stroma that are not organized into granal stacks.
Layered rock-like structures created by mineral deposits in microbial mats containing cyanobacteria. Fossilized stromatolites in Archean rocks may have been formed ~3.5 billion years ago.
Extension of the ovary that bears the stigma. Pollen tubes grow down through the style to reach the ovule.
Tubular mouthpart of some nematodes and aphids that pierces plant cells and withdraws cell contents.
Waxy, waterproof cell wall polymer in specific locations in the plant; synthesized from phenolic and fatty acid monomers.
Acquisition by a duplicated gene of a subset of the functions of the original gene before duplication.
Plants with water-storing parenchymatous tissue in fleshy leaves or stems.
Disaccharide sugar; the primary product of photosynthesis and the main form in which carbon is transported in most plants.
Class of glycerolipids abundant in thylakoid membranes in which position 3 of the glycerol backbone is linked to a sulfonated sugar.
Pigments including flavanol glycosides and anthocyanins that accumulate in leaf cell vacuoles and provide protection against UVB. See also pigments.
Highly reactive forms of oxygen that can damage biological molecules. See also reactive oxygen species (ROS).
Soil in which growth of the same crop over several years results in a rhizosphere microbiome that suppresses specific root diseases.
Cellular structure that connects a developing plant embryo and its maternal tissues.
Agricultural practices designed to achieve increased crop yields with lower inputs of water and agrichemicals.
Participant in a symbiotic interaction.
Close, often long-term association between different species from which both species benefit.
In rhizobia, large cluster of genes involved in symbiosis located in the chromosome or on a plasmid.
In endosymbiotic interactions, a double-enveloped cell compartment containing the endosymbiont. The inner envelope is generated by the endosymbiont; the outer envelope (the perisymbiotic membrane) is derived from the host cell plasma membrane.
Nitrogen fixation carried out by bacteria living in symbiotic associations with plants.
Cell contents bounded by the plasma membrane and connected by plasmodesmata; as distinct from apoplast.
Membrane proteins that simultaneously transport two different types of substrates in the same direction across the membrane.
Process by which homologous chromosomes are aligned (or “zipped”) together during zygotene of prophase I in meiosis.
Structure that unites homologous chromosomes during prophase I of meiosis.
Single, large cell with multiple nuclei, derived from fusions of uninucleate cells.
Cells of the female gametophyte that flank the egg cell and have a role in reception of the pollen tube.
Proteins that integrate into membranes and thus allow the membranes to fuse; for example, SNARE proteins.
See synteny.
The occurrence of similar blocks of genes in the same order on chromosomes of different but related species.
See systemic acquired resistance.
Activation of a defense response in healthy leaves following a hypersensitive response to localized pathogen exposure of a lower leaf.
Tomato signal peptide produced in response to wounding and involved in acquisition of systemic resistance.
Layer of cells in the anther that encloses and nourishes the developing pollen grains.
DNA sequence in the promoter of many genes transcribed by RNA polymerase II that defines the transcription initiation site.
DNA that is transferred to plant cells by the pathogenic bacterium Agrobacterium tumefaciens.
Array of short repeated DNA sequences at either end of a eukaryotic chromosome.
Regions between 23.5° and 66.5° N/S with mean temperatures of -3 to 18°C in the coldest month.
Relating to changes in the developmental timing and location of a plant process.
Wild progenitor of maize (corn, Zea mays).
Compounds formed from two, or multiples of two, isoprene units, with many, diverse functions in plant cells.
Outer of the two maternal integuments surrounding a seed; part of the seed coat. Often forms a hard, protective layer at seed maturity.
Protein complexes on vesicle surfaces that mediate recognition of and attachment to their target membrane.
Having four copies of the basic set of chromosomes.
Compounds with a ring structure that can bind a metal at the center, e.g., chlorophyll (binds Mg2+) and heme (binds Fe2+).
Heating of floral or inflorescence organs of a small number of species, brought about by high rates of uncoupled respiration.
Proteins involved in redox signaling, maintenance of cellular redox homeostasis, and several other redox-modulated processes.
Internal membranes in chloroplasts, sites of the light reactions of photosynthesis. See also granal thylakoids, stromal thylakoids.
Agrobacterium tumefaciens plasmid required for plant infection: carries the T-DNA transferred into host cells.
Mechanical preparation of soil for the growth of crops.
Side shoots from the base of a grass plant.
In angiosperms, extension of a cell protrusion by addition of material at the tip, seen in pollen tubes and root hairs.
In vitro growth of cells or tissues on a sterile, artificial medium, usually in controlled conditions.
In plant cells, the membrane that surrounds the vacuole.
Protein kinase that promotes plant growth when sugar level (energy status) is high. Antagonizes the actions of the growth-inhibiting protein kinase SnRK1.
Water-conducting cells of the xylem, with thickened, lignified cell walls. See also xylem vessels.
Plants with a vascular system containing xylem and phloem.
See RNA transcript.
Synthesis of an RNA transcript from a DNA template.
Proteins that control the rate of gene transcription through binding to gene regulatory regions.
Transcription factors or associated (coactivator, corepressor) proteins that activate or repress gene expression.
Coordinated changes in level of expression of genes involved in a particular process, brought about by changes in transcription factors or their inhibitors in response to a specific stimulus.
See gene silencing.
Total transcript complement of a cell, organ, or plant at a defined point in time.
Cells with convoluted wall invaginations, involved in uptake of metabolites e.g., sucrose from the apoplast.
RNA molecule that binds a specific amino acid then donates it to a nascent peptide on a ribosome by means of a triplet sequence complementary to the appropriate mRNA codon.
Transfer of foreign DNA into an organism’s genome using either Agrobacterium-mediated or biolistic transformation.
A foreign gene introduced into a genome by transformation. Also transgenic plant; a plant carrying a transgene.
N-terminal amino acid sequence that directs nuclear-encoded proteins to plastids or mitochondria.
Process by which the information in messenger RNA is converted into the amino acid sequence of a protein.
See start codon.
See stop codon.
Protein complexes responsible for translocation of newly synthesized proteins from the cytosol into organelles: TOC and TIC complexes in chloroplast envelopes and TOM and TIM complexes in mitochondrial envelopes.
In flowers, structure in the center of a style through which a pollen tube grows after germination on a stigma.
Movement of water through a plant from the soil via the root, the xylem, and the leaf to the atmosphere, driven primarily by evaporative loss of water through stomata. See also soil–plant–air continuum.
Proteins in cellular membranes that carry (translocate) specific molecules or ions across the membrane.
Mechanism by which a transposon becomes inserted into a new genomic location.
Mobile DNA elements capable of movement into new genomic locations with or without replication.
Means of identifying genes through transposon-induced mutations: transposon “tags” enable identification of the mutated genes.
In actin filaments, the simultaneous, equal gain of subunits at the plus end and loss at the minus end.
Sucrose-signaling metabolite and regulator of sucrose homeostasis in plants.
Storage lipids in which all three positions on the glycerol backbone have fatty acid substituents.
Metabolic cycle in mitochondria that oxidizes pyruvate to generate reducing power (NADH), ATP (via oxidative phosphorylation), substrates for biosynthetic pathways, and CO2.
Hairlike outgrowth from the epidermis of shoot organs, consisting of a single modified cell or multiple cells.
Having three openings; tricolpate pollen has three furrowed openings in its wall.
Protein in the inner membrane of the chloroplast envelope that exports triose phosphate in exchange for inorganic phosphate.
Response of a dark-grown seedling to the hormone ethylene: inhibition of root and hypocotyl elongation; exaggerated tightening of the apical hook; swelling of the hypocotyl.
Containing three copies of the basic set of chromosomes.
Region between 23.5°N and 23.5°S with mean temperatures of 18°C or higher in the coldest month.
Below-ground vegetative storage organs that arise from underground stems (stolons) or roots.
The protein component (monomer) of microtubules.
State of a plant cell under turgor pressure, in which cell contents are exerting pressure on the cell wall; as distinct from plasmolysis. See also turgor.
Pressure of plant cell contents against the surrounding cell wall. See also turgid, plasmolysis.
Apparatus by which bacterial pathogens deliver effector proteins via a pilus into plant cells.
Apparatus by which Agrobacterium delivers a T-DNA into plant cells.
Small protein attached by E3 ubiquitin ligases to target proteins, marking them for destruction by a proteasome.
Gametes with different chromosome numbers, produced due to failure of meiotic chromosome pairing or partitioning; as distinct from balanced gametes.
Without distinct adaxial and abaxial identities.
Characteristic or feature of offspring that is inherited from one, rather than both, parents; as distinct from biparental.
Membrane protein that transports a molecule or ion through a membrane without coupling to transport of another molecule or ion.
Particular genes or traits that are always inherited independently; as opposed to genes or traits exhibiting genetic linkage.
Gametes that are diploid rather than haploid due to aberrant cell divisions during meiosis.
See fatty acids.
Somatic instability of a mutation or its phenotype arising from excision or insertion of a transposon.
See open reading frame.
Untranslated regions of DNA at the 5’ and 3’ end of ORFs, with regulatory functions in translation initiation and termination.
Membrane-bounded compartment important in cell growth, control of turgor, and storage of e.g., sugars, acids, pigments, macronutrients, conjugated toxins.
Components of the vascular system: strands of conducting tissue consisting of the xylem, phloem, and fiber cells.
Lateral meristem of woody eudicot stems and roots that produces secondary xylem to the inside and secondary phloem to the outside. Also called fascicular cambium.
In plants, network of conducting tissues that transports water and metabolites (primarily sucrose) throughout the plant.
Agents of transfer of biological activity.
In pollen, cell that forms the pollen tube but does not participate in fertilization.
In plants, transition from a juvenile, vegetative phase to an adult phase in which flowering can occur.
See vascular system.
Pattern of veins in a leaf.
Exposure of a plant to a period of cold that is essential for later flowering and reproduction in that species.
Small membrane-bounded organelles that carry cargo between cellular compartments, and between compartments and the cell surface.
Small, circular, single-stranded RNAs with no protein coat that cause disease by hijacking host plant RNA replication machinery.
Ability of a pathogen to overcome plant host defense mechanisms and establish disease.
Obligate intracellular parasite unable to replicate outside the host. Viral particles usually consist of DNA or RNA in a capsid.
Means of silencing a plant gene of interest through transgenic introduction of a viral vector carrying its nucleic acid sequence: plant RNA-induced silencing complexes (RISCs) primed with viral RNA degrade the mRNA produced from the introduced gene.
Germination of seeds prior to maturity, while still attached to the mother plant.
Ion channels in a membrane that open and close in response to changes in membrane potential.
In plants, state in which there is a lower (more negative) water potential outside than inside a cell or organ, leading to water loss from the cell or organ.
Measure of the free energy of water in a system relative to that of pure water at 100 kPa. Water moves from high to low water potential regions.
Component of photosystem II that splits water to provide electrons to the PSII reaction center with release of O2.
Amount of carbon gained in photosynthesis per unit of water lost in transpiration.
Long-chain, hydrophobic aliphatic hydrocarbons found in the cuticle.
Doubling of the whole chromosome set; within a species or following hybridization of two species. See also polyploidy.
The four concentric rings of floral organs in a eudicot flower: sepals, petals, anthers, and carpels.
In plant breeding, cross-pollination of two related but incompatible species to produce an embryo that can be rescued by tissue culture.
In plant breeding, a wild species that gave rise to a crop through domestication.
Genotype or phenotype that predominates in a natural population of plants; as distinct from mutant.
In photosynthesis, dissipation of excess excitation energy in PSII chlorophylls by interconversion of xanthophyll pigments.
Plant species able to grow in arid environments.
Vascular tissue that transports water and mineral nutrients from the root to the shoot.
Long, pipe-like water conducting cells of the xylem. In angiosperms, water is conducted by both tracheids and xylem vessels; in other tracheophytes only tracheids are present.
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Class of storage proteins found in maize kernels.
A diploid cell resulting from fertilization (fusion of male and female gametes).
Depiction of electron transfer in the light reactions of photosynthesis that shows the reduction potentials of components during the process.