Abstract
The GAs (gibberellins) comprise a large group of diterpenoid carboxylic acids that are ubiquitous in higher plants, in which certain members function as endogenous growth regulators, promoting organ expansion and developmental changes. These compounds are also produced by some species of lower plants, fungi and bacteria, although, in contrast to higher plants, the function of GAs in these organisms has only recently been investigated and is still unclear. In higher plants, GAs are synthesized by the action of terpene cyclases, cytochrome P450 mono-oxygenases and 2-oxoglutarate-dependent dioxygenases localized, respectively, in plastids, the endomembrane system and the cytosol. The concentration of biologically active GAs at their sites of action is tightly regulated and is moderated by numerous developmental and environmental cues. Recent research has focused on regulatory mechanisms, acting primarily on expression of the genes that encode the dioxygenases involved in biosynthesis and deactivation. The present review discusses the current state of knowledge on GA metabolism with particular emphasis on regulation, including the complex mechanisms for the maintenance of GA homoeostasis.
- gibberellin biosynthesis
- gibberellin deactivation
- gibberellin homoeostasis
- plant development
Abbreviations: ABA, abscisic acid; AG, AGAMOUS; AGF1, AT-hook protein of GA feedback 1; bHLH, basic helix–loop–helix; bZIP, basic leucine zipper; CBF, C-repeat-binding factor; CHO1, CHOTTO1; CPS, ent-copalyl diphosphate synthase; DAG1, DOF AFFECTING GERMINATION 1; DDF, DWARF AND DELAYED FLOWERING 1; DIF, difference between day temperature and night temperature; DOG1, DELAY OF GERMINATION 1; DRE, dehydration-response element; DREB, DRE-binding; EUI, ELONGATED UPPERMOST INTERNODE; FUS3, FUSCA3; GA, gibberellin; GA2ox, GA 2-oxidase; GA3ox, GA 3-oxidase; GA20ox, GA 20-oxidase; GAMT, GA methyl transferase; GGPP, trans-geranylgeranyl diphosphate; GGPS, trans-geranylgeranyl diphosphate synthase; GID, GIBBERELLIN-INSENSITIVE DWARF; GUS, β-glucuronidase; HY5, ELONGATED HYPOCOTYL 5; JAZ, JASMONATE ZIM-domain protein; KAO, ent-kaurenoic acid oxidase; KNOX, KNOTTED-like homeobox; KO, ent-kaurene oxidase; KS, ent-kaurene synthase; MADS, MCM1 (minichromosome maintenance1), AGAMOUS, DEFICIENS and SRF (serum-response factor); LD, long day; LEC, LEAFY COTYLEDON; MS, male-sterile; ODD, 2-oxoglutarate-dependent dioxygenase; P450, cytochrome P450 mono-oxygenase; PCD, programmed cell death; PIF, PHYTOCHROME-INTERACTING FACTOR; PIL5, PIF3-LIKE 5; RGA, REPRESSOR OF ga1 (DELLA protein); RGL3, RGA-LIKE PROTEIN 3; RSG, REPRESSION OF SHOOT GROWTH; SCL3, SCARECROW-LIKE 3; SD, short day; SLR1, SLENDER1; SOM, SOMNUS; SPT, SPATULA; T-DNA, transferred DNA; YAB1, YABBY1
- © The Authors Journal compilation © 2012 Biochemical Society
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May 2012
Volume: 444 Issue: 1
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