Molecular mechanisms integrating fungal growth with plant innate immunity suppression

通过解决“真菌细胞如何在植物细胞中茁壮成长？”这一基本问题，本项目旨在解决植物病理学中的实质性问题，即真菌在宿主细胞中的代谢和生长与植物先天免疫持续抑制之间的分子机制。该项目涉及正向和反向遗传学、全基因组蛋白质组学和代谢方法，以及活细胞成像，以了解稻瘟病菌在宿主水稻细胞中的生长和代谢是如何促进的，并与宿主免疫抑制有关。这可能会导致针对真菌生长至关重要但不是宿主细胞正常功能所必需的分子途径的新型作物保护策略的发展，并可能为细胞生长的基本原理以及宿主-微生物界面的性质和调节提供新的思路。教育目标将通过刺激本科生的科学学习，为研究生的科学生活做准备，以及激发未被充分代表的高中生的科学兴趣来扩大科学教育。为了引起植物疾病，与其他与植物相关的微生物一样，破坏性稻瘟病菌Magnaporthe oryzae最初与活的水稻细胞形成密切联系，并在感染的最初几天作为无症状的生物营养菌生长，精心制作被植物源膜包裹的侵入性菌丝（IH），获取营养并在细胞间传播时逃避水稻的先天免疫反应。感染3-5天后，m.o ryzae经历一个生活方式转变为坏死，导致疾病症状发展，宿主细胞死亡和叶片病变产生孢子。m.o ryzae如何在生物营养生长期控制IH的发展，同时逃避或抑制宿主先天免疫，以及在延长的生物营养生长期后触发向坏死转变的原因，在分子水平上几乎完全未知。该项目旨在通过产生和表征无法定植寄主植物细胞的m.o ryzae突变体来解决这些知识空白。这有望揭示控制水稻感染的新的细胞、生化和遗传机制。这项工作的结果可能指出抗病的新来源，阐明植物宿主-微生物相互作用的基本概念，并指出如何促进有益的植物-真菌相互作用，同时减少那些对作物健康有害的相互作用。这项工作将通过积极参与解决稻瘟病的现实问题，促进来自不同背景的博士后、研究生和本科生的分子训练。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

By addressing the fundamental question "How do fungal cells thrive in plant cells?" this project aims to resolve substantial issues in plant pathology regarding what molecular mechanisms integrate fungal metabolism and growth in host cells with sustained plant innate immunity suppression. The project involves forward and reverse genetics, genome-wide proteomic and metabolic approaches, and live-cell imaging to understand how the growth and metabolism of rice blast fungus in host rice cells is facilitated and linked to host immune suppression. This could lead to the development of novel crop protection strategies targeting molecular pathways that are critical for the growth of the fungus but are not required for the normal function of the host cell, and could shed new light on both the basic principles of cell growth, and on the nature and regulation of host-microbe interfaces. The educational objectives will expand scientific education by stimulating undergraduates' science learning, preparing graduate students for scientific life beyond the university, and inspiring scientific interest in underrepresented high school students.In order to cause plant disease, and in common with other plant-associated microbes, the devastating rice blast fungus Magnaporthe oryzae initially forms intimate associations with living rice cells and grows for the first few days of infection as a symptomless biotroph, elaborating invasive hyphae (IH) wrapped in plant-derived membranes, acquiring nutrients and evading rice innate immune responses as it spreads cell-to-cell. After 3-5 days of infection, M. oryzae undergoes a lifestyle transition to necrotrophy, resulting in disease symptom development, host cell death and sporulation from leaf lesions. How M. oryzae controls the development of IH during the biotrophic growth phase while simultaneously evading or suppressing host innate immunity, and what triggers the transition to necrotrophy following the extended biotrophic growth phase, is almost entirely unknown at the molecular level. This project seeks to address these knowledge gaps by generating and characterizing mutants of M. oryzae that are unable to colonize host plant cells. This is expected to uncover novel cellular, biochemical, and genetic mechanisms governing rice infection. Results from the proposed work could point to novel sources of disease resistance, shed light on fundamental concepts of plant host-microbe interactions, and indicate how beneficial plant-fungal interactions might be promoted while those detrimental to crop health are diminished. The work will foster the molecular training of postdoctoral, graduate and undergraduate students from diverse backgrounds through active participation in tackling the real-world problem of rice blast disease.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.