miR535-3p调控水稻纹枯病抗性的功能研究

The function of Osa-miR535-3p in resistance to sheath blight disease in rice

纹枯病是水稻生产中最重要的病害之一,其病原物立枯丝核菌(Rhizoctonia solani)是一种典型的土传真菌。前期我们通过立枯丝核菌侵染水稻后转录组测序,发现多个水稻内源miRNA响应R.solaniAG1-IA的侵染,其中Osa-miR535-3p的表达在R.solani侵染后被抑制。为明确Osa-miR535-3p在水稻应答R.solani侵染中的功能,本研究分别构建了Osa-miR535-3p在感病品种Xudao3背景下的敲除和过表达材料。发现与Xudao3相比,Osa-miR535-3p敲除系的纹枯病发病程度显著加重,而其过表达系的发病程度明显减轻。Osa-miR535-3p敲除系的二级枝梗数目增多、穗长增加、分蘖数减少、千粒重增加,而其过表达系的株高降低、二级枝梗数目减少、穗长变短、分蘖数增多、千粒重下降,表明Osa-miR535-3p也参与调控水稻的农艺性状。通过RNA-seq通路分析,发现Osa-miR535-3p主要是通过影响植物激素信号通路如乙烯(Ethylene,ET)、吲哚乙酸(3-Indoleacetic acid,IAA)等信号相关基因的表达,调控水稻对纹枯病的抗性。本研究结果将为进一步解析水稻抗纹枯病分子机制提供理论参考,同时将为抗纹枯病水稻品种培育提供新思路。

Sheath blight is one of the most important diseases in rice,the pathogen Rhizoctonia solani is a typical soil-borne disease.Our previous study found that there were several endogenous miRNAs in response to R.solani infection in rice.Here,our data showed that the expression of Osa-miR535-3 p was inhibited by R.solani infection.We constructed knockout and overexpression materials of Osa-miR535-3 p,respectively.After infected by R.solani,the disease incidence displayed more serious in Osa-miR535-3 p knockout plants compared with the control plants,while the disease incidence was significantly reduced in overexpression plants.In addition,the agronomic traits of transgenic rice have also significantly affected:the overexpression plants of Osa-miR535-3 p showed decreased height and secondary branches,shorter panicle length,decreased thousand-grain weight,and increased tillers.While,the knock-out plants of Osa-miR535-3 p presented increased secondary branches,increased panicle length,decreased tillers,and increased thousand-grain weight.By RNA-seq,a few genes,including plant hormone signaling pathway related genes,especially,Ethylene(ET)and 3-Indoleacetic acid(IAA)were involved in response to R.solani infection.Taken together,our results suggested that Osa-miR535-3 p positively mediated rice immunity against R.solani and impacted on the agronomic traits in rice.