太子参玉米黄质环氧化酶基因克隆及表达探析.doc

太子参玉米黄质环氧化酶基因克隆及表达探析 　　[摘要] 玉米黄质环氧化酶（zeaxanthin epoxidase，ZEP）在植物脱落酸（abscisic acid，ABA）生物合成间接途径中发挥着重要调节作用。该研究根据太子参转录组数据，克隆获得太子参的Pseudostellaria heterophylla玉米黄质环氧化酶基因，命名PhZEP。对其序列进行生物信息学分析，结果表明PhZEP的开放阅读框（open reading frame，ORF）为1 263 bp，编码420个氨基酸，预测其蛋白的相对分子质量为47.34 kDa，等电点（theoretical pI）为6.64；具有脂质蛋白附着点和黄素蛋白单加氧酶的特征性结构域，且在N端含有分泌信号肽。实时荧光PCR分析发现，PhZEP在叶片中表达量最高，其次是茎和须根；PhZEP在盛花期后10，40 d块根中的表达量较高；ABA处理后PhZEP表达量与对照组相当，经氟啶酮处理后PhZEP的表达量显著高于对照组。该研究从太子参中分离鉴定了ZEP基因，对后续研究其基因的功能特点和解析ABA在太子参生长发育过程的遗传调控提供研究基础 [关键词] 太子参； 玉米黄质环氧化酶； 克隆； 表达分析 [Abstract] Zeaxanthin epoxidase plays an important role in indirect pathway of plant abscisic acid biosynthesis. According to the data of Pseudostellaria heterophylla transcriptome， zeaxanthin epoxidase gene was isolated and named as PhZEP. The results of bioinformatics analysis showed that the coding sequence of PhZEP was 1 263 bp long and encoded 420 amino acids. The putative protein molecular weight was 47.34 kDa and its theoretical isoelectric point was 6.64. The characteristic structure domains were predicted， including binding site of lipoprotein and flavoprotein monooxyenase. A signal peptide was discovered at the N-terminal of amino acids. The Real-time PCR revealed that PhZEP had a higher expression level in leaves than other tissues of P.heterophylla. Highly expressed PhZEP was also observed at 10 d and 40 d tuberous root after flowering. PhZEP presented a different expression after treatment with ABA， fluridone and ABA +fluridone compared to the control. The expression of PhZEP in tuberous root after ABA treatment was close to that in control group， while PhZEP showed significant up-regulation in the fluridone treatment group. In this study， the PhZEP gene from P. heterophylla was cloned and this result has important significance for its functional identification. This research provides a basis for the further analysis on functional mechanism of ABA during development of P. heterophylla. [Key words] Pseudostellaria heterophyll