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Gibberellin‐regulated plant genes
Author(s) -
Huttly Alison K.,
Phillips Andrew L.
Publication year - 1995
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1995.tb00843.x
Subject(s) - aleurone , biology , promoter , gene , gibberellin , chalcone synthase , gene expression , structural gene , endosperm , mutant , response element , transcription factor , transcription (linguistics) , microbiology and biotechnology , genetics , linguistics , philosophy
Gibberellins (GAs) are involved in the control of a number of key developmental processes in plants, including endosperm mobilisation stem elongation and flowering. In many of these systems, GA modulates the transcription of specific genes. The aim of this paper is to review current progress in identifying and characterising GA‐regulated genes; both the control of gene expression and the function of the gene products are discussed. The most well‐characterised system in which GA is active in controlling transcription is the aleurone layer of cereal grains, where it induces the synthesis of a range of hydrolytic enzymes, including a ‐amylase. Analysis of the promoters of a‐Amy1 and a‐Amy2 genes by transient expression in aleurone cells and protoplasts together with DNase 1 footprinting and gel‐retardation assays, has identified a number of cis ‐acting elements important for high‐level, GA‐regulated expression. In particular a GA‐response element (GARE) including the sequence TAACRRA has been characterised. Recent reports describe cDNA clones encoding trans ‐acting factors that bind to elements in the a ‐amylase promoters. Expression of the factor capable of binding to the TAACRRA element is itself induced by GA. In elongating tissues, GA has been shown to control the expression of a number of genes, including the tonoplast intrinsic protein, a water channel which may regulate water flux into the vacuole during cell expansion. In flower development, expression of flavonoid biosynthetic genes, such as chalcone synthase in Petunia corollas, is regulated by GA at the level of transcription. Analysis of GA‐response mutants led to the suggestion that one consequence of GA action is to regulate its own biosynthesis. Genes encoding GA 20‐oxidase and 3β‐hydroxylase have recently been shown to be down‐regulated by applied GA, providing a possible mechanism for feedback regulation of the GA biosynthetic pathway. There is evidence that cells perceive GA at the cell surface, implying the existence of a signal transduction system between plasma membrane and nucleus. This signal transduction system has barely begun to be elucidated but is likely to become a major focus of gibberellin research.