紫杉醇是一种具有高效抗癌特性的二萜类物质,其生物合成途径一直是科学家们研究的热点。‘金锡杉'是南方红豆杉变种,相较于原种含有更加丰富的紫杉醇,因此是一种重要的遗传资源。本研究以‘金锡杉'为材料,运用生物信息学方法分析了紫杉醇合成途径中两种关键酶基因GGPPS(geranylgeranyl diphosphate synthase mRNA)和TDC1(taxadiene synthase mRNA)的序列结构,并采用半定量RT-PCR技术分析了它们的时空表达模式。生物信息学分析结果显示,基因GGPPS全长为1 889 bp,其编码的蛋白质GGPPS是一种不稳定的亲水性胞内酶。基因TDC1全长为2 700 bp,其编码的蛋白质TS是一种不稳定的脂溶性胞内酶。时间表达分析结果显示,GGPPS和TDC1在春季和夏季时期都有表达且均在春季表达量最高,该结果表明GGPPS和TDC1的表达受到季节更迭的影响。组织表达分析结果显示,GGPPS和TDC1在‘金锡杉'的树叶、树皮、树枝和果实中都有表达且两个基因在不同组织中呈现不同表达趋势。GGPPS在树叶中表达量较高,而TDC1在树皮中表达量较高,这些结果表明GGPPS和TDC1的表达同样具有组织特异性。该研究为寻找提高红豆杉中紫杉醇含量的方法提供了一定的理论基础。

Paclitaxel is a diterpene substance with high anti-cancer properties. Its biosynthetic pathway has been a hot topic for scientists. ‘Jin Xishan' is a variant of Taxus chinensis, which contains more taxol than the original species and is therefore an important genetic resource. In order to further explore the expression characteristics of key enzyme genes in the paclitaxel synthesis pathway, we used bioinformatic methods and semi-quantitative RT-PCR to analyze the sequences and the spatio-temporal expression patterns of GGPPS and TDC1 in ‘Jin Xishan', which were two key enzyme genes in the paclitaxel synthesis pathway. Bioinformatics analysis showed that the full length of the gene GGPPS is 1 889 bp. It encoded protein GGPPS belongs to intracellular enzyme, which is hydrophilic and unstable. The full length of the gene TDC1 is 2 700 bp. It encoded protein TDC1 belongs to intracellular enzyme, which is fat soluble and unstable. Time-expression analysis showed that both GGPPS and TDC1 were expressed in spring, which indicated that the expression of both genes was affected by the season. The results of tissue expression analysis showed that GGPPS and TDC1 were expressed in the leaves, bark, branches and fruits, however the expression levels of the two genes in different tissues were different. GGPPS showed higher expression in leaves and TDC1 in Higher expression levels in the bark indicate that both GGPPS and TDC1 are tissue-specific. This study provides a certain theoretical basis for increasing the taxol content in yew.