Expression Of BvCPD Gene And Cloning And Analysis Of Its Putative Promoter Region In Suger Beet (Beta Vulgaris L.)

Beta vulgaris L.was the main sugar-making crop,and the sugar production was mainly from roots.The alternation of the external environment can directly affect the economic traits,such as root weight and sugar accumulation.Therefore,it is necessary to explore the development of sugar beet roots under different cultivation conditions.Based on the transcriptome study of beet root development,the expression pattern of Brassinosteroid(BR)synthase gene BvCPD related to root development was analyzed,and the 5'-end deletion fragment of the promoter region was cloned and transformed into Arabidopsis thaliana,which can be laid a theoretical foundation for elucidating the molecular mechanism of BvCPD gene catalytic synthesis of BR to regulate beet root development in different environments.The results from this study are as following:(1)BvCPD gene expression responds to environmental conditions and plant hormones.Drought stress can induce the up-regulation of BvCPD expression,and BvCPD expression can be down-regulated by light-protection and low-temperature stress;BR can inhibit the expression of BvCPD by negative feedback regulation;application of brassonidazole(BRz)can up-regulate the expression of BvCPD,jasmonate A Ester(MEJA),abscisic acid(ABA),and salicylic acid(SA)caused a down-regulation of BvCPD expression.(2)The Plant CARE promoter prediction software was used to analyze the 3100 bp sequence of the ATG of the BvCPD transcriptional translation initiation site.The results showed that the promoter region contains typical cis-acting elements TATA-motif and CAAT-motif in eukaryotes,15 phytohormone response elements,19 photoresponsive elements,8 environmental stress response elements,5 development-related components,and 13 cis-acting elements had no clear function or are not classified.(3)Three 5'-end deletion fragments of the BvCPD gene promoter region were cloned from sugar beet(SD13829),1412 bp,804 bp and 432 bp,referred as BvCPD-P1,BvCPD-P2 and BvCPD-P3 respectively.After sequencing,the sequence has two more thymine bases than the genomic sequence,and the remaining sequences are completely identical.(4)The BvCPD-P1,BvCPD-P2 and BvCPD-P3 promoter fragments all had priming activity using the tobacco GUS transient expression system.Further analysis showed that all three promoter fragments were able to drive the expression of the GUS gene by heterologous priming activity by transgenic Arabidopsis.(5)The expression of GUS in the transgenic Arabidopsis driven by BvCPD-Pl/P2/P3 promoter fragment was up-regulated compared with the untreated group,and was down-regulated under the shading condition.The results indicated that the BvCPD promoter is regulated by drought,low temperature and light.