Abstract
In Arabidopsis thaliana, it is currently thought that the core circadian clock is composed of the CCA1/LHY and TOC1 gene-products, which together generate a fundamental circadian rhythm by forming a negative/positive transcriptional feedback loop. This intrinsic Arabidopsis clock plays roles in a variety of biological processes, which are common in higher plants. So far, nevertheless, no mutant lacking all these clock genes, CCA1, LHY, and TOC1, has yet been characterized. Here, we characterized for the first time such a cca1 lhy toc1 triple loss-of-function mutant with reference to the circadian clock-associated phenotypes, including, for instance, the photoperiodic control of flowering time and the light-regulated hypocotyl elongation. To gain insights into the molecular picture of plant clock, based on the results of this and other studies, a unified view as to the sophisticated genetic linkages among these clock-associated core genes will be proposed.
