LcMYB1激活荔枝花色苷生物合成关键基因LcDFR和LcUFGT1的启动子区域分析

花色苷含量是荔枝果实呈现鲜红色的重要次生代谢产物,前人研究结果表明,LcMYB1通过调控关键基因的表达而影响荔枝果皮中花色苷的积累,其中LcDFR和LcUFGT1是荔枝果皮花色苷生物合成的关键基因,但是LcMYB1如何影响基因的表达,是否与结构基因启动子结合以及具体结合区段目前还不清楚.本研究通过克隆和分析LcDFR和...

Identification of Interaction Region Between LcMYB1 and Promoters of Anthocyanin Biosynthetic Genes LcDFR and LcUFGT1 in Litchi chinensis

The accumulation of anthocyanins is one of the most important factors in determining the pericarp coloration of litchi. LcDFR (dihydroflavonol 4-reductase) and LcUFGT1 (UDP-glucose: flavonoid 3-O-glucosyltransferase) are two crucial enzymes in the anthocyanin biosynthesis pathway of litchi pericarp, and the activities and gene expressions directly affect litchi fruit coloration. Previous study showed that the expressions of LcDFR and LcUFGT1 were regulated by the LcMYB1 transcription factor. However, how LcMYB1 regulates the expression of the target genes, whether LcMYB1 binds to their promoter, which cis-element in the promoter is the binding site of LcMYB1 remain to be uncovered. In this study, the promoters of LcDFR (1927 bp) and LcUFGT1 (1584 bp) were cloned and analyzed respectively. Six candidate MYB binding sites and some other cis-elements such as light responsive elements and hormone related elements were predicted. The promoters of the two genes were then fragmented and ligated to pGreen-0800-luc plasmid to drive the expression of luciferase (LUC). Dual luciferase assay indicated that LcMYB1 could activate 904 bp to 1425 bp region of LcDFR promoter and 610 bp upstream of LcUFGT1 gene, which contain 1 and 2 candidate MYB-CORE sites, respectively. The interaction was also confirmed by the yeast one hybrid assay. These results suggested that LcMYB1 regulated the biosynthesis of anthocyanins by directly targeting the promoters of key structural genes and the binding region was narrowed down.