FUNCTIONAL DIVERSIFICATION OF THE CAROTENOID-<i>CIS-TRANS</i>-ISOMERASES CrtISO, CrtISO-L1, AND CrtISO-L2 IN TOMATO SPECIES (<i>SOLANUM</i>, SECTION LYCOPERSICON)

Abstract

The expression of the genes of carotenoid-cis-trans isomerases CrtISO, CrtISO-L1 and CrtISO-L2 was studied in comparison with the content of carotenoids in tomato species with different ripe fruit colors: green (Solanum habrochaites), yellow (S. cheesmaniae) and red (S. pimpinellifolium and S. lycopersicum). More ancient origin of CrtISO-L2 was shown in relation to CrtISO and CrtISO-L1. A similar content of total carotenoids (leaves) and β-carotene (ripe fruits) was found between the samples. Unlike fruits of S. habrochaites and S. cheesmaniae, red fruits accumulated lycopene and 20-30 times more total carotenoids. The highest level of transcripts both in leaves and in ripe fruits was detected for CrtISO. The CrtISO-L1 and CrtISO-L2 were transcribed high in leaves and low in fruits, except for the high expression of CrtISO-L2 in S. lycopersicum fruits. No relationship was observed between the content of carotenoids and the level of gene expression in the fruit. In the leaves, a positive correlation between the amount of carotenoids and the levels of CrtISO-L1 and CrtISO-L2 transcripts was found.