桂花‘莲籽丹桂’芳樟醇合酶基因OfTPS5的克隆及功能鉴定

Molecular Cloning and Functional Characterization of Linalool Synthase Gene OfTPS5 in Osmanthus fragrans ‘Lianzi Dangui’ Flowers

以桂花(OsmanthusfragransLour.)‘莲籽丹桂’为材料,从基因组数据库中克隆到1个萜烯合酶基因OfTPS5,鉴定其序列信息及功能,分析其表达规律及其与香气形成的关系。结果表明,OfTPS5(Gen Bank登录号为MN366471)的开放阅读框为1 770 bp,编码589个氨基酸,其编码的蛋白质具有萜烯合酶基因家族的保守结构域,属于TPS-g亚家族。序列比对发现它与其他芳樟醇合酶基因的同源性在50%左右。OfTPS5在盛花期高表达,且呈现明显的昼升夜降的节律变化,其转录表达水平与单萜类物质芳樟醇及其衍生物的合成呈正相关。烟草瞬时表达试验证明,OfTPS5可催化形成芳樟醇。由此推测,OfTPS5在桂花萜类香气形成中发挥重要作用。

This study was conducted to isolate a linalool synthase gene from Osmanthus fragrans Lour.‘Lianzi Dangui’based on genome sequences. Functional identification,expression analysis and the relation with aroma compound formation were investigated. The gene was designated as OfTPS5(Gen Bank accession No. MN366471). Sequence analysis demonstrated that the open reading frame(ORF)was 1 770 bp,and putatively encoded 589 amino acids. The OfTPS5 contained conserved domains and belonged to TPS-g subfamily. Multiple sequence alignment analysis demonstrated that it has approximate 50% homology with other plant TPSs. The transcript expression of OfTPS5 reached high level at the full bloom stage with a significant circadian rhythm,which also showed positive correlation with the aroma compound formation. Further transient expression in tobacco leaves proved that OfTPS5 was capable of producing linalool. Thus,OfTPS5 might play an important role in terpenoid biosynthesis in O. fragrans flowers.