Expression of phytoene synthase (psy) gene and its relation with accumulation of carotenoids in tea [Camellia sinensis (L) O Kuntze]

Carotenoids are important determinant of tea quality as many of the quality related flavour volatiles are produced through the degradation of carotenoids during tea processing. Variation in levels of carotenoids including neoxanthin, violoxanthin, xanthophylls and -carotene in early and late period of spring, summer and autumn seasons in two tea cultivars were investigated. The relationship of phytoene synthase (psy) gene expression to the accumulation of carotenoids in tea was studied. The results showed that carotenoids level in late period of a plucking season was consistently higher than its early period though carotenoids accumulation patterns of the two tea cultivars over different plucking periods was different. The carotenoids accumulation showed a strong seasonal dependence for the expression of psy gene and psy gene transcript abundance is considered to be an important indicator for screening tea cultivars with high level of carotenoids.