川西獐牙菜SmC4H基因的生物信息学分析和表达分析

Bioinformatics Analysis and Expression Analysis of SmC4H Gene in Swertia mussotii

由Sm C4H基因编码的肉桂酸-4-羟基化酶是川西獐牙菜苯丙烷途径的关键酶。本研究从川西獐牙菜的转录组数据中获得了SmC4H基因的全长cDNA序列,通过RT-PCR进行该基因的克隆鉴定,利用生物信息学软件对该基因进行预测分析,并通过RT-qPCR检测该基因的组织表达差异和不同胁迫处理条件下的表达情况。生物信息学分析结果显示SmC4H基因c DNA全长1 518 bp,编码505个氨基酸,相对分子质量为51.83 kD,为亲水性较强的不稳定蛋白,二级结构由47.52%α-螺旋、14.06%延伸链、4.95%β-转角和33.47%无规则卷曲构成,预测该蛋白可能不具有跨膜结构,不含有信号肽,属于p450超家族。SmC4H蛋白的相似性与其他植物的C4H蛋白较高,其中与美女樱(Glandularia×hybrida)的相似性最高。RT-qPCR结果显示,SmC4H基因在根、茎、花、叶中均有表达,表达量根>茎>花>叶,硝普钠(SNP)、赤霉素(GA3)和脱落(ABA)在一定程度上能使SmC4H基因的表达上调。此结果为进一步研究该基因在川西獐牙菜苯丙烷途径中的功能和通过基因工程手段提高呫吨酮化合物产量奠定了基础。

The cinnamic acid 4-hydroxylase encoded by SmC4H gene is the key enzyme of phenylpropanoid pathway in Swertia mussotii Franch.In this study,we obtained the full-length cDNA of the SmC4H gene according to the transcriptome of Swertia mussotii.Meanwhile,the gene was cloned and identified by RT-PCR,predicted and analyzed by bioinformatics software,and detected the tissue and stress conditions expression by RT-qPCR.The prediction of bioinformatics analysis showed that SmC4H gene cDNA was 1 518 bp in length,encoded 505 amino acids,had a relative molecular mass of 51.83 kD.It was a highly hydrophilic unstable protein with a secondary structure consisting of 47.52% alpha helix,14.06% extended strand,4.95% beta turn and 33.47% random coils.The prediction showed that the protein had no transmembrane structure and signal peptide,belonging the P450 superfamily.SmC4H protein had high similarity with C4H proteins of other plants,and with the highest similarity to Glandularia×hybrida.The RT-qPCR results showed that SmC4H gene was expressed in different tissue and the highest expression was found in roots.Sodium nitroprusside(SNP),gibberellin acid(GA3) and abscisic acid(ABA) could up-regulate the the expression of Sm C4H.The recults of this study will provide a foundation for further research on the function of SmC4H gene in phenylpropanoid pathway of Swertia mussotii and using genetic engineering to increase the yield of xanthones.