Abstract
We screened new bil mutants from Arabidopsis activation tag lines and isolated three mutants. Screened W114 showed long hypocotyls witn Brz in the dark. In the light, W114 showed slender dwarf phenotype with excessive epinastic leaves, and thin and shorter inflorescences. Compared with wild-type, the number of inflorescences, branches and siliques was increased in W114. In the long day condition, W114 showed slower growth than wild-type. In contrast, W114 showed the early flowering phenotype in the short day condition. Identification of the tag insertion on the W114 genome is in progress. The second mutant bpg2 was screened as pale green phenotype with Brz in the light. A T-DNA insertion was identified in a cover gene ORF on bpg2 genome. bpg2 possessed GTPase homologous domain and seventh hydrophobic regions. Possible localization of bpg2 into chloroplast was predicted by TargetP program. The Toc and Tic was well-known as GTPase on chloroplast outer membrane. The amino acid sequence of bpg2 showed no homology with those of the Toc and Tic. The third semidominant mutant Z1 had a normal etiolated hypocotyl as wild-type in the dark, but when grown on the medium with Brz, hypocotyl of Z1 became about half length of wild-type with Brz. The phenotype could be said that Z1 hypocotyl is hypersensitive to Brz. As the hypocotyl shortening of Z1 could not recovered by auxin, gibberellins and cytokinins, dwarf phenotype of Z1 could be brassinosteroid specific dwarf phenotype.
