Abstract
LHY, CCA1, TOC1 and GI have been suggested to be essential clock components or closely related to clock function in Arabidopsis. Loss-of-function of both LHY and CCA1 causes acceleration of flowering under short days (SD). We demonstrated that the early flowering phenotype of lhy cca1 double mutant under SD condition would be mainly caused by 1) the phase shift of GI expression, 2) the phase shift of CO expression into the daytime and 3) drastic up-regulation of FT expression. FT expression is mainly regulated by GI-dependent pathway. On the other hand, SOC1 that may have partial redundant function with FT on floral promotion shows rather different expression features from those of FT in several multiple mutants. Here we show that a circadian clock may regulate SOC1 expression by GI-dependent and -independent manners.
