Abstract
In Arabidopsis, phyB, cry2 and phyA are photoreceptors that regulate flowering. Recent reports have demonstrated that these photoreceptors regulate stability of CO protein and FT gene expression. However, how these photoreceptors regulate FT expression is still unclear.
We found two mutant alleles of At1g72390 containing a T-DNA insertion line (SALK) or a missense mutation (TILLING). These mutants, named the phytochrome-dependent flowering (phf), exhibited late flowering phenotype under continuous white light. Analyses of the phyB phf and the cry2 phf double mutants under various light conditions suggested that PHF suppressed the phyB-dependent delay of flowering. The phf mutants showed low FT and SOC1 expression. However, CO expression was normal. Furthermore, a physical interaction between PHF and PHYB was detected by the yeast two-hybrid assay and pull-down assay.
We concluded that PHF is a novel protein that suppresses the delaying effect of phyB on flowering.
