Abstract
GAMYB is known as a transcriptional factor, which binds to the promoter of α-amylase gene and activates the GA-dependent gene expression. Recently we found GAMYB is also important in anther development from microscopic analyses of gamyb mutant.
We performed the microarray analysis using RNAs from gamyb anthers. The expression of many genes, related to fatty acid synthesis, flavonoid synthesis, cell wall degradation, and protein degradation, was down regulated in the mutant. Gel shift assay confirmed that some of them contain the GAMYB-interacting elements in their 5`-flanking regions. We also performed same experiment using anther RNA from GA-deficient mutant, oscps-1. Genes down regulated in cps, were almost overlapped with those in gamyb. This suggests that GAMYB works in down-stream of GA signaling in anther as well as in aleurone, and promotes the expression of genes related to various nutrient supplies from tapetum to pollen and cell death of tapetum.
