A comparison of the carotenoid accumulation in Capsicum varieties that show different ripening colours: deletion of the capsanthin-capsorubin synthase gene is not a prerequisite for the formation of a yellow pepper.
Ripe pepper (Capsicum sp.) fruits can display a range of colours from white to deep red. To understand better the regulatory mechanisms of the carotenoid biosynthetic pathways that underlie these ripening colours, Capsicum varieties that show seven different fully ripe colour types were analysed. The levels and composition of the carotenoid accumulation in these samples at different stages of ripening were measured, and the resulting data were analysed in conjunction with the expression patterns of the carotenoid biosynthetic genes. It was found that red peppers accumulate increasing levels of total carotenoids during ripening, whereas non-red peppers accumulate lower levels of total carotenoids of varying composition. The expression levels of the phytoene synthase, phytoene desaturase, and capsanthin-capsorubin synthase (Ccs) genes are high in peppers with high levels of total carotenoid, whereas one or two of these genes are not expressed in peppers with lower levels of total carotenoid. Surprisingly, it was found that the Ccs gene is present in two Capsicum varieties whose ripe colour is yellow. This gene has never previously been shown to be present in yellow peppers. Sequence analyses of the Ccs gene further revealed two structural mutations in yellow peppers that may result in either a premature stop-codon or a frame-shift. Taken together with the fact that the Ccs transcript is not detectable in yellow peppers, our current results suggest that nonsense-mediated transcriptional gene silencing of Ccs and not the deletion of this gene is responsible for yellow ripening in Capsicum.
Ha
Sun-Hwa
SH
National Institute of Agricultural Biotechnology, RDA, Suwon 441-707, Republic of Korea. shha@rda.go.kr
Kim
Jung-Bong
JB
Park
Jong-Sug
JS
Lee
Shin-Woo
SW
Cho
Kang-Jin
KJ
D001483:Base Sequence; D015152:Blotting, Northern; D002212:Capsicum / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology; D002338:Carotenoids / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D018744:DNA, Plant; D017353:Gene Deletion; D020869:Gene Expression Profiling; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics*; D016133:Polymerase Chain Reaction
D018744:DNA, Plant; D010940:Plant Proteins; D002338:Carotenoids; D010088:Oxidoreductases; C086535:CCS protein, Capsicum annuum