Functional Genomics of Plant Disease Defense Pathways

植物病害是全世界作物生产的最大障碍之一。因此，人们一直致力于了解遗传抗性的机制，并将其纳入育种计划，以抵消病原体造成的产量损失。本项目将重点研究具有良好特征的大麦-白粉病病理系统，以解决寄主-植物抗性的基本问题。在该模型系统中，大麦对专性真菌病原菌蓝灰菌（Blumeria graminis f. sp. hordei）的抗性由大麦抗性基因（Ml）和相应的白粉病无毒基因（AvrMl）的特定组合控制。本提案的总体目标是利用大麦、水稻和拟南芥的功能基因组学工具和资源，加速对农业中重要的疾病防御途径的比较分析。该团队将利用mla指定的大麦-白粉病相互作用的详细分子遗传学，作为跨越广泛分类界限研究防御基因功能的起点。在第一年和第二年，该团队将利用公开可用的大麦基因芯片，这是一个统一的RNA分析平台，可以在一次实验中调查22,000个谷物基因。具有多种Mla抗性等位基因和相关突变体的近等基因大麦品系将用于鉴定抗病网络中的重要新基因。项目数据将被整合到BarleyBase （http://barleybase.org/）中，以促进对共调节基因的生物信息学和统计分析。在第2 - 4年，大麦和拟南芥的高通量反向遗传系统将用于对单子叶和双子叶植物抗性途径中的候选基因进行功能验证。来自这些研究的表型数据将确定单个基因对总体抗性反应的贡献。拟议项目的更广泛影响将通过积极参与“分子生物技术和基因组学”NSF-REU中心，科学与工程女性计划，以及NSF-NIH-BBSI在爱荷华州立大学的生物信息学暑期研究所来完成，在那里，那些没有机会在本国机构参与研究的科学本科生将参与其中。通过NSF-RET计划（http://www.plantgenomeoutreach.eeob.iastate.edu/），将邀请7-12年级的生物教师到参与实验室进行暑期实习。这个多学科团队将为研究生和博士后研究人员提供整合基因组学、植物-病原体相互作用、统计学和生物信息学的高级培训机会。通过谷物微阵列、BarleyBase、ArrayExpress和NCBI-GEO的在线关系数据库，全球公众可以访问所有项目数据，这将加强这一点。因此，这些活动将促进研究、教育和向广大受众传播我们的成果，同时培养新一代农业科学家。

Plant diseases are among the greatest deterrents to crop production worldwide. Hence, major efforts have been devoted to understanding the mechanisms of genetic resistance and incorporating them into breeding programs to offset yield loss caused by pathogens. This project will focus on the well-characterized, barley-powdery mildew pathosystem to address fundamental questions in host-plant resistance. In this model system, resistance to the obligate fungal pathogen, Blumeria graminis f. sp. hordei, is controlled by the specific combinations of barley resistance genes, designated Ml, and corresponding powdery mildew avirulence genes, designated AvrMl. The overall objective of this proposal is to utilize functional genomics tools and resources available to barley, rice, and the model dicot Arabidopsis thaliana, to accelerate comparative analysis of disease defense pathways important in agriculture. The team will exploit the detailed molecular genetics of Mla-specified, barley-powdery mildew interactions as a launching point to investigate defense gene function across wide taxonomic boundaries. In years 1 & 2, the team will take advantage of the publicly available Barley1 GeneChip, a uniform RNA profiling platform that allows the investigation of 22,000 cereal genes in a single experiment. Near-isogenic barley lines that possess various Mla resistance alleles and associated mutants will be utilized to identify significant new genes in disease resistance networks. Project data will be integrated into BarleyBase (http://barleybase.org/) to facilitate the bioinformatic and statistical analysis of co-regulated genes. In years 2 to 4, high-throughput reverse genetic systems in barley and Arabidopsis will be used to functionally validate candidate genes in resistance pathways of both monocot and dicot plants. Phenotypic data from these studies will establish the contributions of individual genes to overall resistance responses. Broader impacts of the proposed project will be accomplished via active participation in the "Molecular Biotechnology and Genomics" NSF-REU Center, the Program for Women in Science and Engineering, and the NSF-NIH-BBSI summer institute in Bioinformatics at Iowa State University, where science-bound undergraduates who do not have the opportunity to participate in research at their home institutions will be involved. Outreach to secondary school students will be undertaken by hosting grade 7-12 biology teachers in participating laboratories for summer internships through the NSF-RET program (http://www.plantgenomeoutreach.eeob.iastate.edu/). This multi-disciplinary team will provide advanced training opportunities for graduate students and postdoctoral researchers that integrate genomics, plant-pathogen interactions, statistics, and bioinformatics. This will be enhanced by worldwide public access to all project data through the on-line relational database for cereal microarrays, BarleyBase, as well as ArrayExpress, and NCBI-GEO. Thus, these activities will promote research, education, and dissemination of our results to a broad audience, while developing a new generation of agricultural scientists.