Correlations of carotenoid content and transcript abundances for fibrillin and carotenogenic enzymes in Capsicum annum fruit pericarp

The fruits of Capsicum spp. are especially rich sites for carotenoid synthesis and accumulation, with cultivar-specific carotenoid accumulation profiles. Differences in chromoplast structure as well as carotenoid biosynthesis are correlated with distinct carotenoid accumulations and fruit color. In the present study, the inheritance of chromoplast shape, carotenoid accumulation profiles, and transcript levels of four genes were measured. Comparisons of these traits were conducted using fruit from contrasting variants, Costeno Amarillo versus Costeno Red, and from F-1 hybrids; crosses between parental lines with novel versions of these traits. Intermediate chromoplast shapes were observed in the F1,but no association between specific carotenoid accumulation and chromoplast shape was detected. Increased total carotenoid content was associated with increased beta-carotene and violaxanthin content. Transcript levels for phytoene synthase (Psy) and beta-carotene hydroxylase (CrtZ-2) were positively correlated with increased levels of specific carotenoids. No correlation was detected between transcript levels of capsan-thin/capsorubin synthase (Ccs) and carotenoid composition or chromoplast shape. Transcript levels of fibrillin, were differentially correlated with specific carotenoids, negatively correlated with accumulation of capsanthin, and positively correlated with violaxanthin. The regulation of carotenoid accumulation in chromoplasts in Capsicum fruit continues to be a complex process with multiple steps for control. (C) 2014 Elsevier Ireland Ltd. All rights reserved.