茶树查尔酮异构酶基因克隆及序列分析

Molecular Cloning and Sequence Analysis of Chalcone Isomerase Gene of Tea Plant (Camellia sinensis)

茶叶是世界上最流行的无酒精饮品之一,含有许多有价值的次生代谢产物,如儿茶素类物质。分离和克隆重要的茶树功能基因,对利用基因工程技术进行茶树遗传调控具有重要意义。本文采用EST测序技术和T4RNA连接酶介导的5′RACE技术,获得了一个茶树儿茶素代谢中的重要基因—查尔酮异构酶(CHI)基因,在GenBank登录(DQ904329),其序列全长1163bp,其中开放阅读框长723bp,编码240个氨基酸,3′端有一个明显的多聚腺苷酸加尾信号,推测的蛋白分子量约为26.4kD,理论等电点为5.19。序列分析表明它与番茄CHI基因序列的亲缘关系比较近。

Tea is one of the most popular non-alcoholic healthy beverages in the world, which possesses great value as a source of secondary metabolic products, such as catechins. Isolation and cloning of important functional genes of tea plant （Camellia sinensis） is of crucial significance for using biotechnology method to regulate the metabolism of tea plant. In this paper, the chalcone isomerase gene, which was an important functional gene of catechins biosynthesis pathway, was cloned from tea plant by using EST sequencing and RACE （rapid amplification of cDNA ends） approaches. The full-length cDNA of chalcone isomerase gene is 1 163 bp （GenBank Accession No. DQ904329）, containing a 723bp open reading frame （ORF） encoding a 240 amino acid protein, and its 3＇ untranslated region has an obvious polyadenylation signal. The deduced protein molecular weight was 26.4 kD and its theoretical isoelectric point was 5.19. Sequence analysis result showed that it is closely related with that of Lycopersicon esculentum.