Rice CYP734As function as multisubstrate and multifunctional enzymes in brassinosteroid catabolism

摘要: *† SUMMARY Catabolism of brassinosteroids regulates the endogenous level bioactive brassinosteroids. In Arabidopsis thaliana, such as castasterone (CS) and brassinolide (BL) are inactivated mainly by two cytochrome P450 monooxygenases, CYP734A1/BAS1 CYP72C1/SOB7/CHI2/SHK1; inactivates CS BL means C-26 hydroxylation. Here, we characterized CYP734A orthologs from Oryza sativa (rice). Overexpression rice CYP734As in transgenic gave typical brassinosteroid-deficient phenotypes. These transformants were deficient both its precursors downstream C-22 hydroxylation step. Consistent with this result, recombinant utilized a range hydroxylated brassinosteroid intermediates substrates. addition, can catalyze second third oxidations to produce aldehyde carboxylate groups at vitro. results indicate that multifunctional, multisubstrate enzymes control content direct inactivation suppression biosynthesis decreasing levels precursors.