【摘要】 MicroRNA(miRNA)是一类内源性非编码小分子RNA,通过指导剪切或者抑制翻译等方式调节植物基因的表达,参与调控植物的生长发育,并在多种非生物与生物胁迫响应中发挥重要作用.但目前关于玉米纹枯病抗性相关miRNA表达调节与功能尚不十分清楚.本研究结合直接克隆法与生物信息学分析,鉴定玉米纹枯病抗性相关9个新的玉米miRNA和已知的zma-miR168a、zma-miR168a*;WMD 3软件进行靶基因预测显示,共获得靶基因总数34个,靶基因功能主要涉及玉米的抗氧化胁迫机制、自身反馈调节、转录调控途径、抗病相关代谢途径以及毒物转运外排等调控过程;实时定量PCR检测miRNA显示,耐感纹枯病材料R15和Ye478叶片和叶鞘中共有9个miRNA受纹枯病感染诱导发生特异性差异表达.本研究结果提示,玉米纹枯病抗性相关miRNA介导的玉米对纹枯病诱导产生可能的抗病途径构成了玉米抗纹枯病侵染复杂的防御机制.更多还原

【Abstract】 MicroRNAs(miRNAs) are a class of endogenous,non-coding,short(21～25 nt) RNA molecules,which regulate target gene expression through miRNA-guided cleavage or translational repression of mRNAs.Plant miRNAs play important roles in the regulation of plant growth,development and the responses to various abiotic and biotic stresses.However,the miRNAs-regulatory networks and their functions in banded leaf and sheath blight(BLSB) were not clear in Zea mays.To investigate the role of miRNAs under BLSB stress,the miRNAs separated from BLSB-stressed Zea mays(R15 and Ye478) were profiled by direct cloning and parallel sequencing.Two previously known miRNAs(zma-168a and zma-168a*) and 9 novel BLSB-responsive miRNAs were identified.The gene targets of these miRNAs were predicted using WMD 3,which were showed to be mainly involved in antioxidant stress,self-feedback regulation,transcription regulation,disease resistance related metabolic pathways and efflux of toxic substance.A total of 9 miRNAs were subsequently validated by quantitative real-time PCR(qRT-PCR).The results suggested that these identified miRNAs might be involved in the sophisticate defense mechanism in maize against BLSB stress.更多还原