稻瘟病是水稻最重要的真菌病害之一，通常稻瘟病抗性研究集中在筛选、鉴定、克隆抗病基因上。miRNA通过调控靶基因参与多种生命活动，但尚不清楚miRNA是如何调控稻瘟病抗性的。我们的前期研究发现miR398b正向调控稻瘟病抗性，过表达miR398b的转基因水稻可明显延迟并减弱稻瘟病菌的侵染，显著提高抗病性。本项目拟在此基础上，通过抗谱测定、抗病细胞学分析、超氧化物迸发、防御相关基因的表达几个方面来剖析过表达miR398b转基因水稻对稻瘟病的抗性；然后通过差异转录组分析绘制miR398b调控稻瘟病抗性的信号通路，找出部分关键调控因子；同时，构建靶基因的过表达和沉默突变体材料，对这些转基因材料进行抗性反应分析及靶基因蛋白的生化功能分析。通过上述三方面的研究，明确miR398b调控稻瘟病抗性的机制，为构筑稻瘟病广谱抗性和水稻抗稻瘟病育种提供有力的理论依据。

Rice blast is the most devastating disease for rice production caused by fungus Magnaporthe oryzae. MiRNAs are involved in regulating diverse biological processes. However, how do miRNAs regulate rice immunity against blast disease is still unknown. Our previous study revealed that the accumulation of OsmiR398b was increased significantly upon blast fungal infection in both susceptible and resistant rice accessions. The expression of defense-related genes was enhanced greatly, whereas the fungal conidial germination and invasive hypha growth were greatly delayed and suppressed on miR398b-overexpressing transgenic plants. These results demonstrate that miR398b positively regulate rice resistance against blast disease. However, the mechanism of miR398b elevating rice immunity is unknown. In this study, we proposed to test the resistant spectrum of miR398b overexpressing lines and evaluate the resistant responses, including subcellular responses to the blast fungal invasion, H2O2 accumulation and expression of defense-related genes.By high-through transcriptional sequencing and bioinformation analysis, the miR398b-regulated resistant signaling pathway will be figured and related regulating genes will be picked out. Furthermore, we plan to construct the target gene-overexpressing or -silencing transgenic rice lines,and identify the functional target by evaluating resistant responses. This project will significantly help us to learn about the mechanism of rice immunity against blast disease, and contribute to applying the resistance in breeding programs.