马铃薯 PDS 和 ZDS 基因的克隆与表达特性分析.

Phytoene desaturase(PDS) and ζ -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 1 752, 1 767 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. [ABSTRACT FROM AUTHOR]