马缨杜鹃查尔酮合酶的基因克隆及表达分析OA

To elucidate the role of chalcone synthase(CHS)in flower color formation of Rhododendron delavayi,the full-length coding region of RdCHS2 was cloned from R.delavayi,and its expression profile,catalytic activity in vitro and biological function in vivo were analyzed.The results were as follows:(1)The full-length coding sequence(CDS)of RdCHS2 was 1 170 bp,encoding 389 amino acids.Phylogenetic analysis showed that RdCHS2 was grouped into the same clade with CHS from other plants and had typical conserved motifs of CHS.(2)Gene expression analysis showed that the expression of RdCHS2 was the highest in scapes and the lowest in stamens,and its expression increased gradually as flowering progressed.(3)Enzymatic assays confirmed that RdCHS2 catalyzed the synthesis of naringenin chalcone from malonyl-CoA and p-coumaroyl-CoA,as well as catalyzed the synthesis of pinocembrin chalcone from malonyl-CoA and cinnamoyl-CoA.(4)Complementation experiments in Arabidopsis thaliana tt4 mutant demonstrated that RdCHS2 successfully restored anthocyanin biosynthesis in cotyledons and hypocotyls of A.thaliana tt4 mutant.These results show that RdCHS2 exhibits typical CHS activity and participates in the biosynthesis of anthocyanin,which lays a foundation for further clarifying the specific function of this gene.