Functional Study Of BvCPD Gene Promoter Of Taproot Development In Sugar Beet

Sugar beet(Beta vulgaris L.)is a kind of sugar crop,its taproot is the main sugar-storage organ.The level of taproot production and quality directly affects the development of sugar industry.Therefore,it is particularly important to improve the yield and quality of taproot.Previously study showed that brassinosteroids(BR)can regulate the growth and development of sugar beet taproot.CPD gene play a key role in brassinosteroid synthase.It is of great significance to clarify the mechanism of BR regulating taproot growth and development.In this study,based on the research group’s analysis of the developmental transcriptome of sugar beet and related gene functional identification,the BvCPD gene expression and BR content in taproot under different growth periods and different environmental conditions,as well as the regulatory characteristics of BvCPD promoter,were studied in order to demonstrate the regulatory mechanism of BvCPD.The main results as following:1 With the growth process of sugar beet,the expression of BvCPD gene and BR content in taproot increased continuously,and reached the maximum in the stage of taproot and sugar growth,and the two were positively correlated,indicating that BvCPD gene may be involved in the synthesis of BR and promote the growth and development of taproot.2 Two pBvCPD::GUS transgenic lines were obtained by agrobacterium transformation of sugar beet.GUS staining of the transgenic plants showed that the promoter had promoter activity and was responsive to low temperature,drought,high salt and dark environments.3 Two proteins,Bvb ZIP1 and BvAREB1,that can bind to the BvCPD gene promoter were found by yeast one-hybrid.Bvb ZIP1 and BvAREB1 genes were up-regulated under low temperature,drought and high salt treatments.It was proved that AREB1 and b ZIP1 transcriptional factors may act as upstream genes of CPD to regulate the expression of this gene.