Home | About | Quick Start | FAQ
Beta Version 0.1
DHARA is an online index of articles on Ayurveda published in research journals worldwide. Users Online: 245
  Enter Keyword Below :
      
Advanced

Proceedings of the National Academy of Sciences of the United States of America 2000 Oct ; (21) :0
Rice dwarf mutant d1, which is defective in the alpha subunit of the heterotrimeric G protein, affects gibberellin signal transduction.

Abstract
Previously, we reported that the rice dwarf mutant, d1, is defective in the alpha subunit of the heterotrimeric G protein (Galpha). In the present study, gibberellin (GA) signaling in d1 and the role of the Galpha protein in the GA-signaling pathway were investigated. Compared with the wild type, GA induction of alpha-amylase activity in aleurone cells of d1 was greatly reduced. Relative to the wild type, the GA(3)-treated aleurone layer of d1 had lower expression of Ramy1A, which encodes alpha-amylase, and OsGAMYB, which encodes a GA-inducible transcriptional factor, and no increase in expression of Ca(2 +)-ATPase. However, in the presence of high GA concentrations, alpha-amylase induction occurred even in d1. The GA sensitivity of second leaf sheath elongation in d1 was similar to that of the wild type in terms of dose responsiveness, but the response of internode elongation to GA was much lower in d1. Furthermore, Os20ox expression was up-regulated, and the GA content was elevated in the stunted internodes of d1. All these results suggest that d1 affects a part of the GA-signaling pathway, namely the induction of alpha-amylase in the aleurone layer and internode elongation. In addition, a double mutant between d1 and another GA-signaling mutant, slr, revealed that SLR is epistatic to the D1, supporting that the Galpha protein is involved in GA signaling. However, the data also provide evidence for the presence of an alternative GA-signaling pathway that does not involve the Galpha protein. It is proposed that GA signaling via the Galpha protein may be more sensitive than that of the alternative pathway, as indicated by the low GA responsiveness of this Galpha-independent pathway.

DHARA ID: D026706 Pubmed ID: 11027362


Access to Full Paper Not Available
Copyright | Disclaimer | Feedback | Updates | Contact
Developed and maintained by AVP Research Foundation (Formerly AVT Institute for Advanced Research), 136/137, Trichy Road, Ramanathapuram, Coimbatore - 641045, Tamil Nadu, India
Funded by Central Council for Research in Ayurvedic Sciences, Dept. of AYUSH, Ministry of Health and Family Welfare, Government of India, New Delhi