Abstract
GAMYB was first isolated as a positive transcriptional regulator of gibberellin (GA)-dependent α-amylase expression in barley endosperm, and its molecular properties has been extensively characterized. Here, we report the role and the regulation of GAMYB and structurally related GAMYB-like proteins in rice growth. We found that GAMYB and GAMYB-like genes contain a target site for a microRNA, miR159, and overexpression of miR159 in rice plant revealed not only the regulatory mode of miR159 on these genes but also the role of these genes in rice growth. On the other hand, microarray experiment revealed that almost all of GA-regulated genes did not respond to GA in the endosperm of gamyb. This suggests that GAMYB is involved in the regulation of almost all GA-mediated gene expression in rice endosperm.
This work was in part supported by PROBRAIN.
