中间锦鸡儿CiMYB15基因正调控拟南芥黄酮代谢

CiMYB15 from Caragana Intermedia Positively Regulates Flavonoids Metabolism of Arabidopsis

目的：R2R3-MYB类转录因子参与调控植物初生和次生代谢。方法：从中间锦鸡儿（Caragana intermedia）干旱转录组数据库中搜索并克隆了一个R2R3-MYB基因,命名为CiMYB15（GenBank登录号MH678649）;将CiMYB15基因编码区转入野生型拟南芥中,利用分光光度法测定了野生型和转基因拟南芥中总黄酮含量,并用qRT-PCR检测了转基因植物中At CHS基因的表达情况。同时采用染色体步移法克隆了CiMYB15基因的启动子序列。结果表明：（1） CiMYB15基因gDNA长度为1 960 bp,包含三个外显子（134、131和521 bp）和两个内含子（281和893 bp）;开放阅读框长度为786 bp,编码262个氨基酸。（2）克隆得到1 580 bp的启动子序列,序列中主要包含损伤诱导元件G-box和P-box、盐诱导作用元件GT1-motif、参与干旱诱导的反应元件MBS,以及真菌侵害应答元件BOX-W1、植物-病原菌互作元件EIER;此外,还包含调节黄酮合成基因的MYB转录因子的结合位点。（3） CiMYB15基因的表达受到紫外胁迫的诱导。（4） CiMYB15基因过表达株系的总黄酮含量高于野生型。（5）过表达植物中At CHS基因的表达量亦高于野生型。以上结果说明,CiMYB15基因正调控拟南芥黄酮代谢。

Objective：R2R3-MYB transcription factors regulate primary and secondary metabolism in plants.Method：A R2R3-MYB encoding sequence,characterized and cloned from drought treated transcriptome of Caragana intermedia,was named as CiMYB15.The gene was transferred into Arabidopsis thaliana,and the total flavonoids contents of transgenic lines and wild type were measured by spectrophotometric method,and the expression of At CHS in transgenic plants was analyzed by qRT-PCR.A 1 580bp fragment of CiMYB15 promoter was isolated by genome walking.The results revealed that：（1）the length of CiMYB15 gDNA was 1 960bp,it’s consisted of three exons（134,131 and 521 bp）and two introns（281 and 893 bp）.The open reading frame（ORF）encodes a polypeptide of 262 amino acids.（2）The main cis-elements of CiMYB15 promoter include abiotic stress responded elements（G-box,P-box,GT1-motif and MBS）,biotic stress responded elements（BOX-W1 and EIER）,and MYB binding sites of flavonoids synthase regulatory genes.（3）The expression of CiMYB15 was induced by UV-B.（4）Total flavonoids contents of CiMYB15 overexpression plants were higher than that of wild type Arabidopsis.（5）Furthermore,the expression level of At CHS was increased in transgenic Arabidopsis.In brief,CiMYB15 positively regulated the flavonoids metabolism.