Nitric Oxide Regulates Mitochondrial Fatty Acids and Promotes CBF Expression of Peach Fruit during Cold Storage

Low-temperature storage is convenient for postharvest preservation of peach fruit,but peach fruit is sensitive to cold damage,which lowers its quality.Nitric oxide(NO)has the potential to improve the bitter resistance of peach fruit.In this work,peach fruit was treated with 15μmol L^(−1)NO and 5μmol L^(−1)c-PTIO[2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxo-3-oxide],to study changes in mitochondrial fatty acids and expression of the C-repeat binding factor(CBF).The results showed that 15μmol L^(−1)exogenous NO significantly maintained fruit quality,reduced peroxidation of mitochondrial fatty acids,increased the activities of the antioxidants superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),ascorbic acid peroxidase(APX),and reduced the content of hydrogen peroxide(H_(2)O_(2)).Meanwhile,NO treatment suppressed the increase in browning index and ion leakage rate,increased the activity of S-nitrosoglutathione reductase(GSNOR),the contents of S-nitrosothiols(SNOs),and the ratios of mitochondrial NAD^(+)/NADH and NADP^(+)/NADPH,increased the expression levels of PpCBF1/5/6.However,the expression levels of PpCBF2/3/4 were not significantly regulated by exogenous NO.Peaches treated with c-PTIO showed opposite effects to those treated with exogenous NO.These results suggest that exogenous NO can improve antioxidant capacity,preserve mitochondrial fatty acids,and upregulate the expression of PpCBF1/5/6 to alleviate cold tolerance and maintain the peach quality during storage.