Synergistic derepression of gibberellin signaling by removing RGA and GAI function in Arabidopsis thaliana.

Journal Article (Journal Article)

RGA and GAI are negative regulators of the gibberellin (GA) signal transduction pathway in Arabidopsis thaliana. These genes may have partially redundant functions because they are highly homologous, and plants containing single null mutations at these loci are phenotypically similar to wild type. Previously, rga loss-of-function mutations were shown to partially suppress defects of the GA-deficient ga1-3 mutant. Phenotypes rescued include abaxial trichome initiation, rosette radius, flowering time, stem elongation, and apical dominance. Here we present work showing that the rga-24 and gai-t6 null mutations have a synergistic effect on plant growth. Although gai-t6 alone has little effect, when combined with rga-24, they completely rescued the above defects of ga1-3 to wild-type or GA-overdose phenotype. However, seed germination and flower development defects were not restored. Additionally, rga-24 and rga-24/gai-t6 but not gai-t6 alone caused increased feedback inhibition of expression of a GA biosynthetic gene in both the ga1-3 and wild-type backgrounds. These results demonstrate that RGA and GAI have partially redundant functions in maintaining the repressive state of the GA-signaling pathway, but RGA plays a more dominant role than GAI. Removing both RGA and GAI function allows for complete derepression of many aspects of GA signaling.

Full Text

Duke Authors

Cited Authors

  • Dill, A; Sun, T

Published Date

  • October 1, 2001

Published In

Volume / Issue

  • 159 / 2

Start / End Page

  • 777 - 785

PubMed ID

  • 11606552

Pubmed Central ID

  • PMC1461816

Electronic International Standard Serial Number (EISSN)

  • 1943-2631

International Standard Serial Number (ISSN)

  • 0016-6731

Digital Object Identifier (DOI)

  • 10.1093/genetics/159.2.777


  • eng