Crucial roles of membrane stability and its related proteins in the tolerance of peach fruit to chilling injury.

Proteome patterns in peach fruit (Prunus persica L.) stored at different low temperatures were examined in order to gain a better understanding why peach fruit is less prone to chilling injury when stored at 0 degrees C than at 5 degrees C. Some differently expressed proteins in peach fruit stored at 0 and 5 degrees C were identified using electrospray ionization quadrupole time-of-flight tandem mass spectrometry. Among these proteins, four membrane stability related proteins, i.e., enolase, temperature-induced lipocalin, major allergen Pru p 1, and type II SK2 dehydrin were enhanced, but three proteins related to phenolic compounds metabolization, cinnamyl-alcohol dehydrogenase 5, cinnamyl-alcohol dehydrogenase 1, and chorismate mutase, were repressed in peach fruit at 0 degrees C as compared to that at 5 degrees C. The abundance of glucose-6-phosphate dehydrogenase, NADP-dependent isocitrate dehydrogenase, and NADP-dependent malic enzyme, which catalyze the reactions during sugar metabolism and energy pathways, was found to decrease in peach fruit stored at 0 degrees C. In addition, our data revealed that low temperature of 0 degrees C might regulate the endogenous H(2)O(2) level, resulting in activating the transcriptional level of genes encoding the proteins related to membrane stability. These results provide a comprehensive knowledge to understand the mechanisms by which peach fruit stored at 0 degrees C showed a higher chilling tolerance than that at 5 degrees C.