The Arabidopsis GAI gene defines a signaling pathway that negatively regulates gibberellin responses 

AUTOR(ES)

Peng, Jinrong

FONTE

Cold Spring Harbor Laboratory Press

RESUMO

The Arabidopsis gai mutant allele confers a reduction in gibberellin (GA) responsiveness. Here we report the molecular cloning of GAI and a closely related gene GRS. The predicted GAI (wild-type) and gai (mutant) proteins differ only by the deletion of a 17-amino-acid segment from within the amino-terminal region. GAI and GRS contain nuclear localization signals, a region of homology to a putative transcription factor, and motifs characteristic of transcriptional coactivators. Genetic analysis indicates that GAI is a repressor of GA responses, that GA can release this repression, and that gai is a mutant repressor that is relatively resistant to the effects of GA. Mutations at SPY and GAR2 suppress the gai phenotype, indicating the involvement of GAI, SPY, and GAR2 in a signaling pathway that regulates GA responses negatively. The existence of this pathway suggests that GA modulates plant growth through derepression rather than through simple stimulation.

Documentos Relacionados

• Expression of Arabidopsis GAI in Transgenic Rice Represses Multiple Gibberellin Responses
• Gibberellin regulates Arabidopsis seed germination via RGL2, a GAI/RGA-like gene whose expression is up-regulated following imbibition
• Extragenic Suppressors of the Arabidopsis gai Mutation Alter the Dose-Response Relationship of Diverse Gibberellin Responses1
• Phenotypic Suppression of the Gibberellin-Insensitive Mutant (gai) of Arabidopsis.
• clr-1 encodes a receptor tyrosine phosphatase that negatively regulates an FGF receptor signaling pathway in Caenorhabditis elegans