吲哚诱导提高水稻抗病性的机理

Mechanism of Indole-induced Improvement of Disease Resistance in Rice

为探究吲哚(Indole)对水稻抗病性的诱导(Priming)作用,本研究使用吲哚预处理‘丽江新团黑谷’(lijiangxintuan-heigu, LTH)水稻离体叶片和接种稻瘟病菌(Magnaporthe oryzae),在不同时间点使用MAPK级联抑制剂(MAPK cascade inhibitors, U0126)抑制促分裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)信号传递途径以及使用NADPH氧化酶抑制剂(NADPH oxidase inhibitors, DPI)抑制活性氧的产生和积累,统计发病情况并检测抗性相关基因的表达。研究发现50 mg/L吲哚预处理48 h可以极大地增强水稻的抗病性,而使用抑制剂后,水稻对稻瘟病菌侵染更敏感、发病率更高,同时相关抗性基因的表达也受到抑制。表明吲哚priming可以诱导产生和积累更多的ROS,ROS激活MAPK级联通路积累MAPK蛋白,促使水稻进入防御准备状态,在受到外来胁迫时,MAPK受诱导信号激活,继而启动下游防御反应增强水稻的抗性。本研究为深入探究吲哚诱导提高植物对腐生型病原菌的抗性提供了参考依据,同时也为吲哚作为天然抗性诱导剂在生态农业中的应用和发展提供科学依据。

To explore indole’s priming effect in rice’s resistance,we used indole pretreat rice detached leaves of’Lijiangxintuan-heigu’(LTH) and inoculated rice blast fungus(Magnaporthe oryzae),preprocessed with MAPK cascade inhibitors(U0126) which inhibit the generation of MAPK signaling pathways and inhibitor NADPH oxidase inhibitors(DPI) which inhibit the production and accumulation of reactive oxygen species at different time.After surveying and measuring the incidence of disease,we analyzed the expression of resistance related genes.The results showed that the 50 mg/L indole pretreatment for 48 hours can greatly enhance rice disease resistance,after using the inhibitor,rice showed higher value of disease incidence and became more sensitive to rice blast fungus infection.Meanwhile the expression of resistance related genes have been suppressed.This results showed that indole priming can quickly generate and accumulate more reactive oxygen species(ROS) and further activate the MAPK cascade reaction to accumulate MAPK protein,then rice can be under defense preparation.When encounter external stress,accumulated MAPK protein receive the indicated signal then enhance the resistance of rice.This study provides a reference for further research on the improvement of plant resistance to saprophytic pathogens induced by indole,and also provides a scientific basis for the application and development of indole as a natural resistance inducer in ecological agriculture.