Expression of Carotenoid Biosynthesis Genes during the Long-Term Cold Storage of Potato Tubers

Carotenoids are secondary metabolites that are synthesized and stored in all types of plant plastids. These pigments play a significant role in protection against oxidative stress, as well as in the coloration of flowers and sink organs. The tubers of potato Solanum tuberosum L. synthesize carotenoids, including during post-harvest storage. In this study, we analyze the expression of carotenoid biogenesis pathway genes ( PSY1 , PSY2 , PSY3 , PDS , ZDS , Z-ISO , CRTISO , LCYB1 , LCYB2 , LCYE , VDE , ZEP , NSY , NCED1 , NCED2, and NCED6 ), as well as genes putatively involved in the initiation of chromoplast differentiation ( OR1 and OR2 ) in the dynamics of the long-term cold storage (September, February, April) of tubers of potato cultivars Barin, Utro, Krasavchik, Severnoe siyanie, and Nadezhda. It is shown that OR1 and OR2 mRNAs are present in tubers of all cultivars at all stages of storage. The expression profile of all analyzed carotenoid biosynthesis genes during tuber storage is characterized by a significant decrease in transcript levels in February compared to September, with some exceptions. During the period from February to April, the level of gene transcripts changes insignificantly. Biochemical analysis of the carotenoid content in the dynamics of cold storage shows that at the time of harvesting, the highest carotenoid content is in tubers of the cv. Utro; tubers of other cultivars are characterized by a similar amount of carotenoids. During storage from September to April, the total carotenoids changed in a genotype-dependent manner without any trend common to all cultivars. In general, the activity of most genes of the carotenoid metabolism pathway during the long-term cold storage of tubers is characterized for the first time, which significantly complements the known data on the expression response of these genes to abiotic stress.