稻瘟病菌附着胞形成阶段代谢组学研究

The rice blast fungus has become the model orgnasim of molecular biology and pathogenesis research in filamentous fungi due to its increasing importance in this area. The specialized infection structure, appressorium, adheres tightly to the plant surface and generates hydrostatic turgor that enables an infection peg to rupture through the cuticle, allowing its entry into the leaf epidermal cell. In this project, 1) Using emerging metabolomics method, we will reveal the ingredients of metabolites in appressorium and identify the key substances, maintaining the turgor pressure of appressorium in M. oryzae；2) By comparing appressorial metabolomics between ΔMoATG1 (autophagy-deficient mutant) and Guy11(wild-type), the role of autophagy in appressorial function will be clarified in the metabolomic level; 3) Further mRNA expression profiles of appressorium (Guy11 vs. MoATG1) in different phases of appressorium formation, combined with the results of metabolomics, representative metabolic compounds will be detected. Functional analysis will also be carried out to elucidate the pathway governing the metabolic process. In summary, the metabolic substances and the key metabolic compounds to maintain turgor will be analyzed in appressoriun of M. oryzae. Pathogenic mechanism will be interpreted deeply and new drug target will be explored.

稻瘟病菌是研究丝状真菌分子生物学和植物病原菌致病机理的研究模式生物，目前对该菌特异的侵染结构-附着胞的了解相对甚少。本项目：1、通过对稻瘟病菌附着胞代谢组学的研究，解析稻瘟病菌附着胞内代谢物组成及其积累变化规律，明确附着胞内维持膨压的主要物质成分；2、通过比较代谢组学，分析稻瘟病菌细胞自噬缺失突变体ΔMoATG1与野生型Guy11的附着胞内含物质的差异，找出差异特征代谢物，明确细胞自噬过程影响的代谢物组分差异及其变化规律；3、进行附着胞不同形成阶段mRNA表达谱测定，结合代谢组学数据，比较稻瘟病菌附着胞形成阶段以及细胞自噬过程中差异特征物质的代谢途径、基因表达调控及其相关基因的功能。通过上述研究，全面揭示稻瘟病菌附着胞内的物质构成，找出维持膨压的关键代谢物，并研究其相关代谢途径基因的表达变化及功能，深层次探明稻瘟病菌致病机理，发掘重要的药物靶点。

稻瘟病菌已成为丝状真菌分子生物学和发病机理研究的重要模式，通过该项目的研究，建立了稻瘟病菌代谢组的方法平台，建立了稻瘟病菌分生孢子，附着胞以及菌丝代谢物数据库。稻瘟病菌分生孢子中分析出42种代谢物，包括糖类，氨基酸，脂类等；稻瘟病菌分生孢子与24h附着胞之间的差异代谢物有31种；0h-24h附着胞代谢物差异比较分析后，发现了5个明显差异代谢通路。稻瘟病菌野生型（Guy11）与细胞自噬突变体（ΔMoATG1）代谢组差异分析（分生孢子阶段）发现有34种代谢物与稻瘟病菌自噬途径相关，差异物以氨基酸差异最为明显，表明细胞自噬突变体相对野生型氨基酸通路的合成明显下降。针对稻瘟病菌附着胞形成过程中重要的代谢物，寻找到关键基因，并进行了关键基因功能分析，发现精氨酸等途径的相关基因在附着胞形成以及成熟过程中发挥重要作用，与稻瘟病菌的致病性密切相关。通过代谢组学分析，我们能够快速，精确的定位关键通路与相关基因，有助于为稻瘟病菌致病机理提供新的研究方向。