Genetic and Molecular Insights into Mechanisms Underlying a Maize Disease

植物与病原体相互作用研究的一个主要目标是阐明宿主易感和抗性反应的机制，最终控制病原体对农业经济的影响。一个病理系统提供了一个独特的机会来解决这些问题在玉米中涉及玉米螟1种，一种真菌病原体。该系统以严重的叶枯病和耳霉病为特征，其关键媒介是hc毒素，一种含环氧化合物的环四肽。hc毒素在疾病病原学中的重要性被强调了，因为它是玉米自然进化的抗病机制的目标，以对抗C. carbonum 1小种。这种抗性机制通过hc -毒素上一个关键羰基的还原而起作用。然而，hc -毒素促进炭疽弧菌1种致病机制的运作方式尚不清楚。深入了解这个问题是本提案的目标，这将通过遗传学和基因组学方法的结合来实现。遗传方法将侧重于鉴定和鉴定不再屈服于病原体感染的玉米突变体。基因组学方法将利用基于DNA微阵列的基因表达谱来鉴定在C. carbonum定植过程中表达受hc -毒素影响的基因。该项目的结果将揭示玉米防御反应的关键成分，以及C. carbonum小种1如何避开这些成分而引起疾病。由此产生的知识和资源将为今后在这一领域取得进展铺平道路，为制定对环境安全和可持续的玉米及其他谷物作物保护战略奠定坚实基础。这项研究将为一名博士后和几名本科生提供遗传学、基因组学、生物信息学和病理学方面的培训机会。

A major goal of research on plant-pathogen interactions is to elucidate mechanisms that underlie susceptibility and resistance responses in the host, ultimately to control the impact of pathogens on the agricultural economy. A pathosystem that provides a unique opportunity to address these questions in maize involves race 1 of Cochliobolus carbonum, a fungal pathogen. This pathosystem is characterized by severe leaf blight and ear mold disease, a key mediator of which is HC-toxin, an epoxide-containing cyclic tetrapeptide. The significance of HC-toxin in disease etiology is underscored by the fact that it is the target for a disease resistance mechanism that evolved naturally in maize to counter C. carbonum race 1. This resistance mechanism operates via reduction of a key carbonyl group on HC-toxin. The modus operandi by which HC-toxin facilitates C. carbonum race 1 pathogenesis however remains unknown. Gaining an insight into this question is the objective of this proposal, which will be accomplished by a combination of genetic and genomics approaches. The genetic approach will focus on identifying and characterizing maize mutants that no longer succumb to infection by the pathogen. The genomics approach will leverage DNA microarray-based gene expression profiling to identify genes whose expression is impacted by HC-toxin during colonization by C. carbonum. The results of this project will uncover key components of the maize defense response and how these components are evaded by C. carbonum race 1 to cause disease. The knowledge and resources generated will pave the way for future advances in this area, providing a firm foundation for the development of environmentally safe and sustainable strategies for crop protection in maize as well as other cereals. This research will provide training opportunities in genetics, genomics, bioinformatics, and pathology to a postdoctoral fellow and several undergraduate students.