Effect of temperature on the expression of genes related to the accumulation of chlorophylls and carotenoids in albino tea

Albino tea (Camellia sinensis) cultivars have white shoots and high concentrations of amino acids when grown at low temperatures. Albinism in tea shoots remains to be investigated. The effect of temperature on the accumulation of chlorophylls and xanthophyll-cycle pigments, and on the expression of related genes in the albino tea cultivar 'Xiaoxueya' were investigated and compared to a common green tea cultivar, 'Fudingdabai'. The concentrations of chlorophylls a and b, neoxanthin, violaxanthin, xanthophyll, and beta-carotene in 'Xiaoxueya' decreased markedly at 15 degrees C, compared to their values at 20 degrees C and 25 degrees C. The expression of genes encoding chlorophyll a/b-binding protein (lhcb), rubisco activase (RCA), the D1 protein in the photosystem II core (psbA), terminal oxidase (TOX), and violaxanthin de-epoxidase (VDE) were suppressed in 'Xiaoxueya' tea leaves at 15 degrees C. These changes led to slower rates of photosynthesis and leaf growth, and resulted in relatively high concentrations of amino acids in the albino tea leaves. Gene expression levels and pigment accumulation were reversible as the temperature increased to 20 degrees C, or above, which resulted in greening of the tea leaves.