藜麦β-香树酯醇合酶和鲨烯合酶基因的克隆与表达

Gene Cloning and Express of Squalene Synthase and β-amyrin Synthase from Chenopodium quinoa

为了探明藜麦皂苷生物合成的分子机制,试验以藜麦品种陇藜1号为材料,利用已有的转录数据,通过RT-PCR技术鉴定参与三萜皂苷生物合成关键酶基因,采用生物信息学分析方法进行了基因编码蛋白保守结构域、蛋白二级结构及系统发育树的构建,并利用半定量RT-PCR方法进行了目的基因在籽粒不同发育时期和植株不同部位(根、茎、叶和籽粒)表达水平的研究。试验克隆得到三萜烯皂苷生物合成途径中关键酶编码基因CqSS1、CqSS2和CqbAS的cDNA全长序列。半定量RT-PCR表达分析表明,CqSS1和CqbAS在叶片、籽粒中表达量最高,各基因在籽粒不同发育时期的表达量间无显著差异。本研究对藜麦三萜皂苷生物合成途径中关键酶基因表达模式的研究,将为进一步探明藜麦皂苷生物合成的分子机制及发掘影响藜麦皂苷含量的关键基因奠定基础。

To explore the molecular mechanism of saponin biosynthesis from Chenopodium quinoa,variety Chenopodium quinoa cv.Longli 1 was used as materials,and experiment was carried out by using RT-PCR technology to identify the key enzyme which involved in triterpenes saponin biosynthesis.Then the conserved domain,secondary structure of protein and phylogenetic tree were analyzed by using bioinformatics methods,and organ-specific expression patterns of genes in seed,root stem and leaf were detected by semi-quantitative RT-PCR.The expression pattern of target gene were also investigated during seed developing period.Full-length cDNAs of CqSS1,CqSS2 and CqbAS were cloned,and gene expression results showed that both CqSS1 and CqbAS were highly expressed in leaf and seed than in other tissues,and express pattern remained in same level in different seed developing stage.This study is the first comprehensive analysis of the expression patterns of pivotal genes for triterpene saponin biosynthesis in Chenopodium quinoa,and provides a basis to further elucidate the molecular mechanism for the., biosynthesis of saponin.