我国是农作物病害严重发生的国家之一，农作物常见病害种类近600种，其中40余种是大面积和高频率发生的、且突发性强的重大病害。这些病害，尤其是重大病害的灾害性发生造成了农作物的严重产量损失和品质下降，威胁着我国粮食的安全供给和农业的可持续发展，是我国急需解决的重大需求。同时，化学农药一直是控制病害的主要措施之一，但化学农药的过量使用引起的人畜中毒、生态环境破坏和植物药害也是国家急需解决的社会问题之一。品种抗病性丧失、抗病资源匮乏和高效低毒农药缺少是造成我国农作物重大病害灾害性发生的三大主要原因，高效低毒农药缺少也是造成人畜中毒、生态环境破坏和植物药害的根本原因。为了有效地控制农作物重大病害在我国的灾害性发生、减少农药的过量使用，必须深入探讨病原物致病性和致病型变异的分子机制，植物与病原物之间直接相互作用的分子机制，植物抗病信号传递途径及其基因网络，病菌抗药性产生的机理等关键科学问题。本项目将围绕这些关键科学问题，在“十五”973计划项目“农作物重大病虫害成灾机理及调控基础的研究”取得突出进展的基础上，继续选取重要粮食作物的重大真菌、细菌和病毒病害为研究对象，设置7个课题，从寄主和病原双方同时开展相应内容的更深入研究。本项目的主要研究内容包括：病原物致病性的分子基础、病原物致病型变异的分子遗传基础与分子流行学机制、寄主抗病基因的克隆及其作用的分子机理、寄主抗病反应的调控机理、新型抗病资源创建策略以及病原菌抗药性的机理及其分子流行学等6个方面。实施这些研究内容的总体目标是：为治理品种抗病性丧失奠定病原物群体小种动态监测和持久/广谱抗病品种培育的理论和技术支持，为解决病毒病等病害控制中的抗病资源匮乏提供创建新型抗病种质资源的理论指导和技术途径，为设计高效环境友好新型农药提供候选靶标，并建立相关抗药性病菌的预警系统。本项目还将在理论上有可能发现一些新的基因及其功能，有助于广泛和深入认识生命过程中基因沉默的机制、分子间相互作用、信号传递途径与基因网络以及基因组进化的规律；并在技术上可望通过改造植物病毒的结构开发出高效的基因沉默载体，为植物功能基因组提供操作平台。本项目的实施，还将促进学科间的相互交叉，为使我国植物病理学科的研究达到国际先进水平，培育一批优秀人才，建立一支强有力的科研队伍。

      China is one of the countries where crop diseases cause severe damage. There are nearly 600 different kinds of crop diseases occurring frequently, of which more than 40 diseases are often epidemic in wide areas. These diseases cause severe loss of crop yields and decline of qualities, which hinders the safe food supplies and threatens sustainable agriculture in China. Therefore, solutions to these issues are urgently required. Meanwhile, one of the main measures used to control diseases is the application of chemical pesticides, however, over-application of chemical pesticides have resulted in poisoning to both human being and livestock, deteriorating the ecological environment and toxicity to plants, which are also the major social problems to be solved urgently. The breakdown of cultivar resistance, the lack of resistance germplasms and the lack of pesticides with high efficiency and low toxicity are the three major reasons that cause main crop diseases to be destructive in China. In order to control the major crop diseases from becoming disaster and reduce the application of pesticides in our country, the key scientific issues must be explored in depth, such as the molecular mechanism of pathogenicity of pathogens and variation of pathotypes, molecular mechanism of interactions between pathogens and plants, signal transduction and gene networks in plant resistance and the mechanism of pathogen resistance to pesticides. To address these issues, we set up this project on the basis of progress achieved in the last 973 project. This project includes 7 subprojects that will accomplish further investigation from both sides of plants and hosts on fungal, bacterial and viral disease in major crops. Emphases will be placed on the mechanisms of pathogenicity of plant pathogens, genetic and epidemic mechanisms of pathotype variations in pathogens, the molecular functions of plant resistance genes, signal transduction mediating plant disease resistance, strategies for generating novel disease resistant resources, mechanisms and molecular epidemiology of pathogen resistance to pesticides, etc. The goals of this project are to establish the theoretical and technical support for monitoring dynamic race changes in pathogen populations and breeding cultivars with durable and broad-spectrum resistance to minimize crop variety resistance losses, provide theories and techniques for developing novel resistant germplasm resources for viral diseases control, supply target candidates for designing novel, highly efficient and environmentally friendly pesticides, and establish forecasting systems for some pesticide-resistant pathogens. This project is also expected to discover some novel genes and their novel functions, and to deepen comprehensive understanding of the mechanism of gene silencing, gene interactions, signal transduction, gene networks and gene evolution in life process. Moreover, this project may provide highly efficient gene-silencing vectors by engineering some plant virus genomes for plant functional genomics studies. The implementation of this project will accelerate the development of interdisciplinary fields and cultivate a strong scientific research team, so that our research can contribute more to advances in plant pathology.