外源一氧化氮对采后桃褐腐病控制的信号诱导及其作用

Recent evidence suggests that nitric oxide (NO) signaling plays an important role in plant-pathogen interactions. In this study, the control effect on brown rot disease caused by Monilinia fructicola and the signal role of NO in the elicitation of defense responses in peach fruit were investigated. It was found that 15 μM NO solution induced disease resistance of harvested peaches and as a potentiated elicitor, NO induced the high production rate of endogenous NO and superoxide (O2ˉ), hydrogen oxide (H2O2) content, and the activities of NADPH oxidase and Ca2+-ATPase of peach fruit. Aconitase activity in peach fruit was inhibited by NO. After partial purified, aconitase activity was inhibited by sodium nitroprusside (SNP) and H2O2, however, the inhibition could be relieved by carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline -1-oxyl 3-oxide (cPTIO) or catalase (CAT), indicating that defense response and signals induced by NO transduction depend on aconitase and conditions leading to elevated levels of NO or H2O2 would inactivate aconitase directly in peach fruit. Treatment with NO resulted in accumulation of salicylic acid (SA) during the period of storage. Higher level of jasmonate acid (JA) were detected in NO-treated fruit 48 h after the treatment. But after NO was removed, the level of SA and JA were lower obviously than that of the control. The results suggest that exogenous NO enhances disease resistance of harvested peach fruit to brown rot disease by inducing some signals such as endogenous NO, reactive oxygen species (ROS), SA and JA and inhibiting aconitase activity.