Abstract
The circadian clock is involved in the regulation of various physiological phenomena. In Arabidopsis, two closely related MYB proteins LATE ELONGATED HYPOCOTYL (LHY) and CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) are essential clock components with redundant functions. Arabidopsis plants with mutations in LHY and CCA1 genes exhibited not only late flowering, but also semi-dwarf phenotypes under continuous light (LL). We have recently found that the late flowering phenotype of lhy;cca1 was suppressed by mutation of elf3, svp and flc (Fujiwara et al., Plant Cell 2008). To understand molecular mechanisms underlying these phenotypes, we have isolated 7 enhancers (petanko 1-7; pta1-7) and 1 suppressors of the phenotypes of lhy;cca1 under LL. We will show results on pta1 and discuss possible roles of PTA1 in the control of flowering time and organ elongation with LHY/CCA1.
