Authors: Kyeonglim Min *, Eun Jin Lee
Capsicum annuum fruit is usually harvested at either mature green or ripe stage, but their texture, color, and nutritive values are different depending on the fruit development stages. It is important to understand fruit ripening in that those quality changes and degradation are accompanied by the ripening. In this study, we aimed to identify a major hormone to regulate fruit ripening by measuring contents of seven hormones according to five development stages of C . annuum 'Gyeonggiyangpyung' fruit, immature-green, mature-green, breaker, turning, and fully-red stages, respectively. Gibberellin 3 and 4, jasmonic acid, and ethylene were not detected in all development stages. Indole-3-acetic acid and salicylic acid contents decreased during the ripening. Abscisic acid (ABA) content significantly increased with the fruit ripening, and exogenous ABA treatment to the breaker stage promoted the ripening. Metabolite profiles showed diverse metabolic changes during the ripening, and accumulations of various sugars, amino acids, fatty acids, and phenolic acids were correlated to the change in ABA content. To identify the genes related to the hormonal regulation for the ripening, expressions of ABA-related genes were investigated. Expressions of ABA biosynthetic genes, including NCED1 , NCED3 , and ZEP , increased during the ripening initiation or progression. ABA core signaling factors belonging to PYL, PP2C, SnRK2 families were also analyzed, and PYR1-like , PYL12 / 12-like , SnRK2.3 / 2.4 , and PP2C 6/ 16-like / 24 / 37 / 50 / 53 were relevant to the ripening. Their protein-protein interactions were investigated through yeast-two-hybrid assay. They worked in ABA signaling during the ripening by interacting each other, especially in the presence of ABA. We revealed that ABA may play a key role in control of the fruit ripening by affecting ABA signaling and metabolic changes. These results will provide genetic information to control ripening and to improve Capsicum annuum fruit quality. This works was supported by the Rural Development Administration (RDA PJ016005022021), Republic of Korea.