油梨蒂腐病菌对油梨果实活性氧代谢的影响

Lasiodiplodia theobromae-induced Alteration on ROS Metabolism in Avocado Fruits

活性氧(reactive oxygen species,ROS)在植物病害发育中扮演重要角色,揭示油梨蒂腐病发病过程中ROS代谢变化规律对于深入了解致病机制和抗病育种具有重要作用。本研究探究了L.theobromae侵染油梨果实期间ROS产生和消除系统的变化特征。研究发现,病原菌L.theobromae在侵染早期诱导了ROS的产生并激活寄主油梨ROS消除系统。随着病情的发展,油梨的抗氧化能力不断削弱,致使ROS积累,促使丙二醛的产生。另外,病原菌L.theobromae的侵染在接种后2~5 d降低了油梨果实中SOD和CAT酶的活性以及AsA和GSH的含量。这些研究发现表明病原菌L.theobromae的侵染引起的病情发展可能归因于ROS消除能力的减弱以及ROS的合成,积累的ROS引起了细胞膜脂的过氧化,破坏了细胞膜的结构,从而导致抗病能力的丧失。反过来,这些ROS也会促进病害的发展。在本研究中,对L.theobromae侵染引发的ROS代谢变化以及其与病情发展的关系进行分析,为后续抗病育种提供一定的理论参考。

Reactive oxygen species(ROS)play pivotal roles in disease development.The information on the alteration of ROS metabolism plays an important role in understanding the mechanism of avocado stem-end rot disease development and disease resistance breeding.In this study,effects of L.theobromae on ROS production-scavenging system during disease development of avocado fruits were investigated.The study found that the infection by L.theobromae led to a ROS burst and activated ROS scavenging system in avocado fruits.With disease progression,the capacity of avocado antioxidant system declined,and allowed for ROS accumulation and eventual malondialdehyde production.Moreover,L.theobromae infection decreased the activities of SOD and CAT,and resulted in reducing contents of As A and GSH from day 2 to day 5.These findings suggested that L.theobromae-induced disease development of avocado fruits might be due to reducing ROS scavenging ability and increasing in ROS production,which might stimulate membrane lipid peroxidation,disrupt cellular membrane structure,and cause the loss of disease resistance,in turn,resulting in enhanced disease development.In this study,L.theobromae-induced alteration in ROS metabolism and its relation to stem-end rot development in avocado fruits were analyzed,providing a theoretical basis for avocado disease resistance breeding.