课题组前期研究发现一个可能与抗病相关的新microRNA: PC-732，然而目前关于PC-732调控抗病性的分子机制尚无人研究。本项目以PC-732及其靶基因为研究对象，采用定量PCR和杂交技术分析PC-732表达模式，通过超量表达和基因沉默技术，明确PC-732在抗病性中的功能；采用5`-RACE、表达负相关性、mRNA 降解、蛋白翻译抑制和亚细胞定位，揭示PC-732对ClMCA1靶向关系和调控机理；比较野生型植株、ClMCA1超量表达和基因缺失突变体对病菌侵入不同阶段的干扰作用、H2O2积累、细胞死亡、ROS清除酶、病斑形成大小、防卫基因表达的影响、ClMCA1与PCD的关系，并结合转录组技术，研究ClMCA1基因调控抗病性分子机制，探讨ClMCA1基因在调控抗病性中的分子机制。研究结果将揭示PC-732抗玉米弯孢叶斑病菌的新机制，为我国培育玉米抗病品种提供理论基础和技术支撑。

In previous study, a new microRNA: PC-732 related to disease resistance was found. However, the molecular mechanism to resistance regulated by PC-732 and its target genes is still unknown. In this project, we use PC-732 and its target gene as the research object. Firstly, we analyze the expression pattern of PC-732 in interaction between maize and Curvularia lunata by quantitative PCR and Northern blot technology, and confirm the PC-732 function in the resistance to Curvularia lunata through over expression and anti-miRNA silencing of PC-732. Secondly, we reveal the targeting relationship and regulatory mechanism between PC-732 and target genes ClMCA1 using 5`-RACE, negative correlation, mRNA degradation and protein translation inhibition analysis. Then, we compare interference role to pathogen invasion on difference stages、H2O2 accumulation，cell death, ROS scavenging enzymes, lesion formation size, expression of defense genes in wild type plants, ClMCA1 overexpression and gene deletion mutants, and analyze the relationship between ClMCA1 and PCD, combined with transcriptome technology, and explore the molecular mechanism of ClMCA1 gene in regulation of plant resistance. The results will reveal the new mechanism of PC-732 in resistance to Curvularia lunata, and provide theoretical foundation and technical support for cultivating resistant varieties of maize.