Abstract
Brassinosteroids (BRs) are plant growth promoting hormones. XTHs (Xyloglucan endotransglucosylases/hydrolases) are BR responsive genes. They may regulate plant growth via cell-wall loosening and reconstruction but the correlations with BR response are not understood.
In this study, we comprehensively screened the BR responsive genes in Arabidopsis thaliana by DNA microarray analysis and MPSS. We then selected the BR responsive genes whose expression correlates with XTHs from the numerous expression data of public database. Here we identify BRR1 as a novel BR responsive ring-finger protein. In two BRR1 knockdown (brr1) lines, production of siRNA from triggered dsRNA and suppression of endogenous BRR1 mRNA were observed. These lines displayed dwarf phenotype. These results show that BRR1 regulates plant growth. We performed DNA microarray analysis between wild type, brr1 seedlings and BL treated brr1 seedlings. We characterized the differentially expressed or BR responsive genes in brr1 by metabolic pathway analysis.
