Collaborative Research: Investigation of the molecular and cellular bases of the maize/Puccinia sorghi interaction

高粱锈病是一种引起普通锈病的真菌病原体，是玉米最具破坏性的病害之一。遗传学和分子生物学方法在鉴定抗宿主蛋白方面取得了重大进展。然而，从真菌分泌的促进发病过程并被宿主抗性蛋白识别的效应蛋白的表征仍然难以捉摸。本研究将利用生物信息学、功能基因组学和先进细胞生物学等互补方法，阐明玉米这一植物数量遗传学模式种和美国头号作物的重要防御机制。由于超敏反应是在所有多细胞植物中发现的一种普遍的防御反应，这一发现将与改善其他重要作物物种，特别是其他禾草有关。研究生、本科生和高中生将在怀俄明大学和北卡罗莱纳州立大学接受作物研究的基本理解和细胞生物学、生物化学和植物-微生物相互作用分子遗传学的尖端方法的培训。学生将作为兼职学生研究人员参与该项目，并在夏季通过暑期研究计划更密集地参与该项目。此外，还计划与NCSU科学馆开展更多的外展活动，向公众宣传遗传学、植物育种、生物技术和相关的社会影响。本项目以本拟烟（Nicotiana benthamiana）为模型，研究真菌病原菌高粱锈菌与玉米互作的分子和细胞基础。玉米Rp1-D基因编码一种NLR抗性蛋白，使其能够抵抗由高粱锈菌引起的普通锈病。分子遗传学研究使用Rp1-D基因的自动活性衍生物鉴定了几个宿主调控成分。然而，由Rp1-D识别的病原体效应蛋白引发的超敏反应性程序性细胞死亡（HR-PCD）迄今尚不明确。本研究将1)确定与控制宿主细胞死亡和抑制宿主防御反应相关的效应物；2)确定这些效应物如何影响宿主细胞的基本生理变化，如pH、活性氧产生和钙通量的变化及其亚细胞定位；3)研究玉米HR与这些生理变化和细胞器动力学的关系，如细胞内基质形成和细胞器间通讯。最终，本研究将表征所有与Rp1-D相互作用的宿主和病原体衍生成分的物理相互作用，这些成分可能构成Rp1-D介导的免疫信号复合物的细胞成分。这将导致对nlr介导的反应的控制的理解，这在玉米中是独一无二的，也是所有植物物种中最详细的。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。

Puccinia sorghi is a fungal pathogen causing common rust, which is one of the most destructive diseases of maize. Genetics and molecular biological approaches made significant progress in the identification of the host-resistant protein. However, characterization of effector proteins secreted from the fungi, which facilitate the pathogenesis process and are recognized by host resistant proteins, remain elusive. This research will elucidate an important defense mechanism in maize, a model species for plant quantitative genetics and the number one crop in the U.S., using complementary approaches, including bioinformatics, functional genomics, and advanced cell biological methods. Since the hypersensitive response is a general defense response found in all multicellular plants, this finding will be relevant to improving other important crop species, particularly other grasses. Graduate, undergraduate, and high school students will be trained in the fundamental understanding of crop research and cutting-edge methods on cell biology, biochemistry, and molecular genetics in plant-microbe interaction at the University of Wyoming and North Carolina State University. Students will participate in this project as part-time student researchers and more intensively during summer via the summer research program. Additional outreach activities are planned with the NCSU Science House to educate the public on genetics, plant breeding, biotechnology, and associated societal implications.The project employs Nicotiana benthamiana as a model to elucidate the molecular and cellular basis of fungal pathogen Puccinia sorghi and maize interaction. The maize Rp1-D gene encodes an NLR resistance protein that confers resistance to common rust disease caused by the fungus Puccinia sorghi. Molecular genetic studies using an auto-active derivative of the Rp1-D gene identify several host regulatory components. However, pathogen effector protein recognized by Rp1-D triggering hypersensitive responsive programmed cell death (HR-PCD) is elusive to date. This research will 1) identify effectors associated with the control of host cell death and suppression of the host defense response, 2) define how these effectors influence essential physiological changes in host cells, such as changes in pH, reactive oxygen species production, and calcium flux, and their subcellular localizations, and 3) examine the maize HR regarding these physiological changes and organelle dynamics, such as stromule formation and inter-organellar communication in the cell. Ultimately, this research will characterize the physical interactions of all the host- and pathogen-derived components that interact with Rp1-D and are likely to constitute cellular components of the Rp1-D mediated immune signaling complex. This will result in an understanding of the control of the NLR-mediated response that is unique in maize and among the most detailed in any plant species.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.