交替氧化酶调控线粒体活性氧在壳聚糖诱导马铃薯抗干腐病反应中的作用机理研究

线粒体是采后果蔬细胞活性氧的主要来源，交替氧化酶是线粒体中调控代谢和信号动态平衡的关键。我们前期发现，采前壳聚糖处理可诱导马铃薯块茎对干腐病的抗性，活性氧参与了诱导抗性过程，但详细机制不明确。本项目拟选用马铃薯为试材，综合采后病理学、细胞生物学、分子生物学和生理生化等多学科方法，通过壳聚糖结合AOX抑制剂SHAM处理，利用细胞器定位观察、透射电镜（TEM）、激光共聚焦显微镜（LSCM）、荧光分光光度计、iTRAQ、qRT-PCR等技术手段，在细胞、分子和生化水平上解析参与壳聚糖诱导马铃薯块茎防御F. sulphureum中，AOX基因的表达及蛋白的种类、对线粒体ROS动态平衡的调控作用，为揭示壳聚糖诱导果实抗病性中的AOX与ROS的积累关系，丰富采后病害的诱抗机理提供理论基础。

Mitochondria are the main source of reactive oxygen species in postharvest fruits and vegetables, and alternative oxidase has important roles to maintain metabolic and signaling homeostasis in mitochondria. Our previous results showed that preharvest treatment with chitosan could induce resistance of potato tubers against dry rot, and reactive oxygen species involved in this process. However, the regulation mechanisms of reactive oxygen species in induced resistance remained unknown. In this proposal, potato tubers will be used as materials, and multidisciplinary approaches involving the postharvest pathology, cell biology, molecular biology, physiology and biochemistry will be used to reveal the types of alternative oxidase gene and proteins implicated in reactive oxygen species homeostasis in potato tubers treated with chitosan and salicylhydroxamic acid (SHAM, an inhibitor of alternative oxidase). With the utilization of modern analyzed methods including organelle positioning observation, transmission electron microscope (TEM), laser confocal microscope (LSCM), fluorescence spectrophotometer, iTRAQ and LC-MS/MS technology, quatitative real-time Polymerase Chain Reaction (qRT-PCR) to explain the mechanism of reactive oxygen species production mediated by alternative oxidase in potato tubers at the cellular, molecular and biochemical level. Expected results of this proposal can elucidate complex relationships of alternative oxidase and reactive oxygen species production homeostasis in potato tubers induced by chitosan, and also provide theoretical basis for further understanding mechanism of induced resistance in fruits and vegetables.