马铃薯PDS和ZDS基因的克隆与表达特性分析

Analysis on Cloning and Expression Characteristics of PDS and ZDS Genes in Potato

八氢番茄红素脱氢酶(Phytoene desaturase)和ζ-胡萝卜素脱氢酶(ζ-Carotene desaturase)是类胡萝卜素合成通路上的关键限速酶,影响植物体内类胡萝卜素的合成。为解析PDS和ZDS在马铃薯类胡萝卜素合成途径中的作用,为马铃薯类胡萝卜素合成的分子调控机理解析和新品种创制奠定基础,研究从黄心马铃薯晋薯16号品种中克隆PDS和ZDS基因,利用生物信息学工具对这2个基因及其所编码的蛋白序列进行分析,并对二者在不同组织内的表达模式进行定量检测。结果表明,克隆得到PDS和ZDS基因长度分别为1 752、1 767 bp,分别编码583、588个氨基酸;StPDS的分子质量为64.97 ku,理论等电点为6.41;StZDS的分子质量为64.73 ku,理论等电点8.51;PDS和ZDS均属于亲水性非跨膜蛋白。系统进化树分析表明,马铃薯晋薯16号的PDS和ZDS分别与番茄PDS和ZDS的同源性最高。通过测定3个不同马铃薯品种晋薯16号、红玫瑰2号和希森8号叶片和薯块中的类胡萝卜素含量,发现在同一组织中,红玫瑰2号的类胡萝卜素含量显著高于希森8号和晋薯16号,这一结果说明,StPDS和StZDS基因可能正向调控马铃薯块茎类胡萝卜素的积累;在同一品种中,类胡萝卜素含量较少的叶片中StPDS和StZDS基因表达量却远远高于块茎中基因的表达量,推测这2个基因可能参与叶片的光合作用。

Phytoene desaturase(PDS)andζ-Carotene desaturase(ZDS)are key rate-limiting enzymes in the carotenoid biosynthesis pathway,they affect carotenoid synthesis in plants.To study the roles of PDS and ZDS in carotenoid synthesis pathway in potato,lay a foundation for the molecular regulation mechanism analysis of carotenoid synthesis in potato and the creation of new varieties,in this study,PDS and ZDS genes were cloned from the yellow-fleshed potato Jinshu 16,bioinformatics tools were used to analyze the two genes and their encoded protein sequences,and their expression patterns in different tissues were quantitatively detected.The results showed that the PDS and ZDS genes cloned were 1752,1767 bp in length,encoding 583 and 588 amino acids,respectively.The molecular weight of StPDS was 64.97 ku with theoretical isoelectric point of 6.41.While the molecular weight of StZDS was 64.73 ku with theoretical isoelectric point of 8.51.Both of PDS and ZDS were hydrophilic proteins without transmembrane structure,and phylogenetic analysis showed that PDS and ZDS in potato had the highest homology with tomato PDS and ZDS.By determining carotenoid content in leaves and tubers of three different potato varieties of Jinshu 16,Xisen 8,and Red Rose 2,it was founded that the carotenoid content of Red Rose 2 was significantly highest than that of Xisen 8 and Jin 16 in the same tissue,which indicated that StPDS and StZDS genes might positively regulate the accumulation of carotenoid in potato tubers.The expression levels of StPDS and StZDS genes in the leaves with less carotenoid content in the same variety were much higher than those in the tubers,suggesting that these two genes might be involved in leaf photosynthesis.