Suppression of late flowering phenotype of lhy cca1 by svp under continuous light condition

Abstract

LHY and CCA1 have been shown to be closely associated with circadian clock function in Arabidopsis. The lhy cca1 mutation causes an extremely early flowering under short days (SD) and late flowering under continuous light (LL). We have found that short vegetative phase (svp) mutation suppressed the late flowering phenotype of the lhy cca1 under LL. The svp in Ler flowered much earlier than svp mutants in Col and a region near the FLC locus on Ch5 has turned out to be responsible for the difference. FLC is a floral repressor and negatively regulates gene expression of floral activators FT and SOC1. The svp was epistatic to the co. Both FT and SOC1 are downstream factors of CO and were up-regulated in the svp suggesting that functional interaction between SVP and FLC may be important for the suppression of the late flowering of the lhy cca1 under LL.