Abstract
The rice (SD plant) orthologs of the three key regulators of flowering time in Arabidopsis (LD plant), GI, CO and FT have been shown to play important roles in the photoperiodic control of flowering in rice. We have previously obtained results suggesting that the GI - CO - FT pathway is conserved in rice and Arabidopsis. Under LD conditions, Hd1 suppresses Hd3a expression in rice. To further study suppression of Hd3a expression by Hd1, we examined the effect of Hd1 on Hd3a gene expression by co-transfection in rice protoplasts. The results indicated that co-transfection of Ubq :: Hd1 cDNA with Hd3a :: gus decreased GUS activity. These results suggest that Hd1 can suppress the promoter activity of the Hd3a gene. We obtained transgenic rice expressing Hd3a :: gus and found that GUS activity was detected in an area surrounding the vascular tissue.
