Mitochondrial membrane permeability transition pores (MPTP) play important roles in mitochondrial function. There are many chemicals in the mitochondria that can act as signal molecules to affect the membrane permeability of mitochondria and mediate to release various enzymes. As a signaling molecule, nitric oxide (NO) is a key player in fruit growth and development. However, the specific mechanism through NO regulates MPTP, and how exogenous NO prolongs fruit storage time are both unclear. In this study, Feicheng peaches were treated with different concentrations of exogenous NO (5, 15 and 30 μmol L-1) and c-PTIO to determine the changes in mitochondrial membrane potential (MMP), hexokinase II activity, the contents of cytochrome C and Ca2+ in mitochondria, as well as the effects of voltage-dependent anion channels (VDAC) and phosphate carrier (PiC) proteins on MPTP during storage. The results showed that NO could form a 1:1 complex either with VDAC or PiC, which proved that NO could react with the protein of PiC or VDAC. Treatment with 15 μmol L-1 NO maintained stable mitochondrial Ca2+ content, and high potential and permeability of the mitochondrial membrane, while decreased cytochrome C content and increased hexokinase activity. When NO was removed, the opposite result appeared. These results indicated that exogenous NO could stabilize MMP and participate in MPTP regulation of peaches during storage.
Keywords: MMP; MPTP; Nitric oxide; Peach; PiC; VDAC.
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