Accumulation characteristics of carotenoids and adaptive fruit color variation in ornamental pepper.

• The fruit color changes of different varieties in different periods were measured. • The contents of three main pigments were determined, and their accumulation with the change of fruit color was clarified. • The expression patterns of genes in carotenoid synthesis pathway was analyzed and several important genes were screened. • The correlation analysis of fruit color, pigment and related genes of ornamental pepper was carried out. To understand better the mechanisms of the pigment accumulation in ornamental pepper, the fruit color, pigment and expression of carotenoid biosynthetic genes were investigated. The test materials were divided into three categories. The first category included cultivars B3, J1, J2 and Q3, the second were M3, M3′, W8 and WU, C2, S1, W3 and W4 belonged to the third category. The pigment changes during ripening were characterized by loss of chlorophyll and anthocyanin, and a rapid accumulation of carotenoids. It was found that GGPS, PSY, CRTZ -2 and CCS genes have abundant transcription during the accumulation of carotenoids in ornamental pepper, which have a more important regulatory function. Correlation analysis were conducted between fruit color, pigment and expression of genes, it showed that there were significant correlation between key genes of carotenoid biosynthetic pathway, among which PSY was highly correlated with CCS and CRTZ- 2 , CCS was highly correlated with CRTZ- 2. Chromaticity values were negatively correlated with anthocyanin content in fruits, and the correlation between a* and carotenoid content was significantly higher. The information will be benefit for exploring the carotenoid regulation mechanism of ornamental pepper, and providing theoretical for fruit color breeding of ornamental pepper. [ABSTRACT FROM AUTHOR]