Searching for Novel BR Biosynthesis Inhibitors

Functions of BRs in Plant Development Unveiled by BR Biosynthesis Inhibitors 

When a BR biosynthesis inhibitor, brassinazole, was applied to Arabidopsis thaliana, high levels of ribulose-l,5-bisphosphate carboxylase-oxygenase proteins accumulated in the plastids of the cotyledons. These results suggest that brassinazole treatment in the dark induces the initial steps of plastid differentiation, which occur prior to the development of fhylakoid membranes. This is a novel presumed function of BRs [16]. Brassinazole treament also retards the development of secondary xylem in cress [17]. 

Brassinazole treatment suppresses BR biosynthesis in cotton ovules and inhibits fiber formation. This inhibition was rescued by brassinolide treatment. These results clearly indicate that BRs are essential for normal growth of cotton fiber 

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