Effect of bagging duration on peach fruit peel color and key protein changes based on iTRAQ quantitation

Abstract

The present study aimed to investigate the effect of bagging duration on the changes in the color and protein profiles in the fruit peel of the honey peach (Prunus persica ‘Hujingmilu’) using iTRAQ techniques. Peach fruits were bagged at 50 days after flowering (DAF), and the bags were removed at 90 (treatment I, short-duration bagging) or 105 (treatment II, long-duration bagging) DAF. Peach fruits used for this experiment were harvested at 50 DAF, 90 DAF, 95 DAF, and 105 DAF, and were stored for 3 days post-picking at 105 DAF. The chlorophyll, anthocyanin, carotenoid, zeaxanthin, and lycopene contents were determined and the key proteins were investigated using iTRAQ techniques. The peach peel color was regulated by chlorophyll degradation, carotenoid metabolism, and anthocyanin metabolism pathways both during development and postharvest. Shortening the bagging duration period could improve the red color and anthocyanin content of peach peel and maintain the stability of anthocyanins, but reduce peel brightness and chlorophyll content. Compared to treatment II, the expression of LHCAB protein and other related proteins in peach peel were not down-regulated in treatmentⅠduring the development but the chlorophyll content was lower of treatmentⅠthan treatment II; It could promote chlorophyll degradation by up-regulating PPR and PAO and not down-regulating LHCAB proteins at 108 DAF. Shortening bagging duration could increase the anthocyanin content, However, the expression of ANS, ANR, 3 G T, and CHS was unaffected at 105 DAF, which could inhibit the degradation of anthocyanin by up-regulating the expression of CHS at 108 DAF. Shortening bagging duration could inhibit the accumulation of carotenoid in peach peel by down-regulating the expression of PSY from 105 to 108 DAF, and decrease the carotenoid content by up-regulating CCD 4 at 108 DAF. The key proteins of peach peel color metabolism during development were LHCAB, PPR, PAO, 3 G T, ANS, and CCD 4; shortening the bagging duration period could affect this by regulating PAO, 3 G T, CHS and CCD 4.