A New Nonsense Mutation in Capsanthin/Capsorubin Synthase Controlling Orange Pepper Fruit

Carotenoids are plant pigments that play a major role in conferring fruit color. Carotenoidcontent is often controlled by genetic variation in the biosynthetic genes. The color of maturepepper fruit is mainly classified as red, orange, and yellow. Orange and yellow fruit colors aredetermined by mutations in phytoene synthase (Psy ) and capsanthin -capsorubin synthase (Ccs ),respectively. In contrast to the current fruit color model, we hypothesized that genetic variationin Ccs also controls orange fruit color in pepper. Ripe fruit of Capsicum annuum ‘K146465’ isorange, and its carotenoid profile obtained by HPLC analysis showed a lack of the major peppercarotenoid capsanthin but an abundance of lutein, zeaxanthin, and β-carotene compared to redpepper. cDNA cloning and sequencing analysis detected a new nonsense mutation due to a T1026insertion in the coding region of Ccs, but no DNA sequence variation in Psy . We developed aderived cleaved amplified polymorphic sequence (dCAPS) marker to distinguish the nonsensemutation in Ccs . Genetic analysis of the F2 population derived from C. annuum ‘Sweet Banana’(red fruit color) × C. annuum ‘K146465’ revealed that orange fruit color is determined by asingle recessive gene. The nonsense mutation in Ccs distinguished by the dCAPS marker cosegregatedwith orange fruit color in the F2 population. This germplasm, coupled with thedCAPS marker and carotenoid profiling, will facilitate marker-assisted breeding to select orangefruit color and improve lutein, zeaxanthin, and β-carotene levels in pepper. KCI Citation Count: 3