Abstract
Brz was synthesized as the first specific inhibitor for brassinosteroid biosynthesis. We had identified Brz insensitive mutant bil1 from EMS-mutation lines, and bil5 from fast neutron-mutation lines. To identify additional components of the brassinosteroid signaling, trial to screen new mutants as Brz-insesitive-long hypocotyls in the dark was applied to Arabidopsis activation-tag lines.
The semidominant mutant bss1(Brz-sensitive-short1) showed normally etiolated hypocotyl same as wild type without Brz in the dark. However, with Brz, bss1 hypocotyl became about 50% length of wild type in the dark. In the weak light, hyocotyl of bss1 showed about 50% length of wild type without Brz. These results suggested that bss1 hypocotyl is hypersensitive to Brz and the light. In the later growth stage, bss1 showed extremely dwarf phenotype by inhibition of axis elongation. Further analysis is in progress.
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