乙烯信号参与调控水稻纹枯病抗性的研究

 乙烯(ET)信号在植物抵抗各种逆境反应中具有重要作用,但目前关于乙烯信号在调控水稻纹枯病抗性中的作用仍缺乏系统研究。本研究以感纹枯病水稻品种Lemont和抗纹枯病水稻品种YSBR1为材料,分析了纹枯病菌接种后乙烯合成关键基因及信号传导途径中标志基因的表达水平,结果显示,纹枯病菌侵染可显著诱导相关基因的表达、激活乙烯信号。进一步采用乙烯合成抑制剂和信号激活剂处理水稻并进行接种鉴定,结果显示,两种化学剂分别可抑制或激活乙烯信号;无论是Lemont还是YSBR1,激活其乙烯信号均可显著增强抗病性,而抑制该信号均显著降低抗病性。对3个乙烯受体突变体(ethylene response2, etr2; ethylene response3, etr3; ethylene response sensor2, ers2)进行温室接种鉴定,发现突变体的病斑长度均极显著高于野生型对照。以上研究表明乙烯信号在水稻对纹枯病菌的防卫反应或基础抗性中具有十分重要的作用,结果将为进一步解析“水稻-纹枯病菌”间的互作机制、制定合适的病害综合防控策略提供理论基础。

A study on ethylene signaling involving in regulating resistance to rice sheath blight

Ethylene (ET) signaling plays important roles in plant defense responses to various environmental stresses, but its role in regulation of rice sheath blight resistance remains to be studied systematically. In this study, a susceptible rice cultivar Lemont and a resistant rice cultivar YSBR1 were used to analyze the expression levels of marker genes in ethylene biosynthesis and signaling pathway after inoculation with R. solani. The results showed that the infection of R. solani significantly induced the expression levels of related genes and activated ethylene signaling pathway. Two chemicals were employed to activate and suppress ET signaling, respectively, on both cultivars. After inoculation with R. solani on both cultivars, we found that activation of ET signaling significantly enhance rice resistance to the pathogen, while suppress the ET signaling apparently reduced rice resistance. Further, we inoculated three ET receptor mutants, etr2, etr3, and ers2, with R. solani at the booting stage in greenhouse. As expect, we found that lesion lengths of the three mutants were all significantly longer than that of the wild type. Taken together, these data demonstrated that ET signaling played an important role in rice defense response or basic resistance to sheath blight. These results provide a theoretical basis for further elucidating the mechanism between "rice - R. solani” and establishing new strategies to prevent and control this disease.