茉莉酸在L-谷氨酸诱导的番茄果实抗性中的作用

The Role of Jasmonate in L-Glutamate Induced Tomato Fruit Resistance

为解析植物激素茉莉酸在化学激发子L-谷氨酸诱导抗性机制中的作用,以番茄果实为对象,经0.1 mg/mL L-谷氨酸和0.1 mmol/L茉莉酸甲酯处理后接种链格孢菌孢子悬浮液,观察果实的发病率。采用实时荧光定量PCR方法从转录水平上分析L-谷氨酸对果实茉莉酸合成路径和信号路径上关键基因表达的影响。结果显示:番茄果实经L-谷氨酸处理后其发病率较对照组下降了35%,而在茉莉酸甲酯处理组中,L-谷氨酸与对照组发病率无显著差异;茉莉酸路径上编码脂氧合酶、丙二烯氧化物合酶、丙二烯氧化物环化酶、冠菌素不敏感蛋白1、转录因子MYC2和蛋白酶抑制剂PI-II的基因不同程度地被L-谷氨酸下调表达,同时茉莉酸信号路径的负调控因子JAZ1则被诱导上调表达。综上,在番茄果实与链格孢菌互作中,L-谷氨酸可能通过抑制果实的茉莉酸路径来调控对病原菌的防御反应,这解析了L-谷氨酸作为激发子响应病原菌侵染的抗性机制,也为其商业化应用提供理论依据。

To decipher the role of jasmonate in chemical elicitor L-glutamate induced resistance to pathogens,tomatoes were treated with 0.1 mg/mL L-glutamate and/or 0.1 mmol/L methyl jasmonate.After inoculating with Alternaria alternata spore suspension,disease incidence of fruit was observed.The effect of L-glutamate on jasmonate biosynthesis and signaling pathways were analyzed by reverse transcription quantitative real-time polymerase chain reaction at the transcriptional level.The results showed that the disease incidence decreased by 35%in L-glutamate treatment compared with the control,while there was no significant difference between L-glutamate and the control in methyl jasmonate group.Concurrently,allene oxide synthase,allene oxide cyclase,coronatine insensitive 1,transcription factor MYC2 and protease inhibitor PI-II were down-regulated by L-glutamate,accompanied by higher expression level of the negative regulator JAZ1.Collectively,the inhibition of JA pathway might be involved in L-glutamate induced resistance to Alternaria alternata in tomato fruit.These findings provided a better understanding for L-glutamate mediated resistance,leading to more sufficient theoretical basis for its commercial application.