Abstract
Brassinosteroids are growth promoting steroid hormones in plants. But it's signal transduction mechanisms remains unclear. To identify new brassinosteroid signaling mutants, we screened these from FOX (Full-length cDNA over-expressor gene) lines, which were transgenic lines overexpressed normalized Arabidopsis full-length cDNAs at random in Arabidopsis. Brz is an inhibitor of brassinosteroid biosynthesis enzyme DWF4 and it's treatment caused to wild type as shorten hypocotyls in the dark. So we tried to screen about 8000 Fox-lines for mutants that showed longer hypocotyls than wild type with Brz in the dark, bil (Brz-insensitive-long hypocotyls) , and isolated about 20 line mutant candidates. These bil candidate mutants showed not only longer hypocotyls on Brz but also various adult phenotypes in rosette leaves as epinastic and in inflorescence as increased or decreased number. Furthermore three mutants showed longer inflorescence than wild type. It appears that the possible overexpressed gene is brassinosteroid signaling factor and promotes inflorescence elongation. Further analyses are in progress.
