Abstract
Brassinosteroids are a group of plant steroidal hormones that regulate various aspects of plant growth and development. We had identified brassinosteroid biosynthesis inhibitor Brz insensitive mutant bill 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-insensitive-long hypocotyls in the dark was applied to Arabidopsis activation-tag lines. We screened Arabidopsis activation-tag lines and isolated bil2 that showed long hypocotyls on the medium containing Brz in the dark. Light-grown bil2 mutants had long petiole phenotype similar to wild-type plants treated with BR or BRIT-OX mutants. These phenotypes suggested that bil2 mutants enhanced the BR signaling. Identification of over-expression the BIL2 candidate gene is progress.
