Abstract
Ehd1 controls Hd3a expression and confers short-day promotion of flowering in rice. We recently found that Ehd1 expression is induced by blue light (BL) in the morning.
GI, a component of circadian clock, acts upstream of CO (a Hd1 ortholog) to regulate the florigen gene in Arabidopsis. Both FKF1 and ZTL, the two F-box proteins with LOV domain, form a complex with GI in a BL-dependent manner to control CO. Here, we isolated osgi mutants as suppressor mutants of an early-flowering and phytochrome-deficient se5 mutant in rice, and revealed that OsGI also can promote Hd3a expression in the absence of Hd1. The BL-dependent expression of Ehd1 was not detected in se5/osgi mutant, suggesting that OsGI activates Ehd1 expression through a similar but distinct mechanism reported in Arabidopsis since Ehd1 expression is induced in response to dawn in rice while the BL induction of CO occurs in late afternoon in Arabidopsis.
