The Difference of Ethylene Biosynthesis and Expression of Softening-related Genes Between Two Peach (Prunus persica) Cultivars with Different Storage Property After Harvest
Abstract Two peach (Prunus persica) cultivars Qinwang (with good storage property) and Shahong (with poor storage property) fruits harvested at commercial maturity were investigated. We analysed the difference of ethylene production through gas chromatography approach, and the genes expressions involed in ethylene biosynthesis and fruit softening between the two peach cultivars by quantitative Real-time PCR PCR (qRT-PCR). The results showed that Qinwang peach remained high firmness during storage accompanied by a quite low expression level of ACC synthase gene (1-aminocyclopropane-1-carboxylic acid synthase gene, PpACS1) and ethylene production rate. However, Shahong softened quikly, and the relative expression of PpACS1 was increased significantly, along with lot of ethylene produced. ACC oxidase gene (1-aminocyclopropane-1-carboxylic acid oxidase gene, PpACO1) expression did not increased in Qinwang while presented rising trend during Shahong softening. In Qinwnag, the expression of pectin methylesterase gene (PpPME) and polygalacturonase gene (PpPG) were extremely low, however, it increased continuously during Shahong softening. In addition, the expression level of expansin gene (PpEXP) was very low in Qinwang compared with Shahong. The gene expression of N-glycan processing enzymes α-mannosidase gene (Ppα-Man) and β-hexosaminidase gene (PpHex1 and PpHex2) expression level were increased in both of Shahong and Qinwang, but the expression in Shahong were significantly higher than that in Qinwang (P＜0.05). These results indicated that the delay of Qinwang fruit softening was due to lack of enough ethylene production by limited expression of PpACS1, which caused PpPME and PpPG expression and enzyme at lower level, unable to take the role in pectins degradation. However, Shahong softened rapidly as a result of production of ethylene, thus, PpEXP, PpPME and PpPG were induced and pectins degradated. Ppα-Man, PpHex1 and PpHex2 maybe not key factors acting on Qinwang softening. This research indicates mechanism of peach fruit ripening and softening, and provides the basic evidence for the long shelf-life peach cultivar breeding.
SU Su-Xiang,DIAO Cai-Beng,CAO Li-Jun, et al. The Difference of Ethylene Biosynthesis and Expression of Softening-related Genes Between Two Peach (Prunus persica) Cultivars with Different Storage Property After Harvest[J]. , 2015, 23(4): 450-458.
