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

高粱柄锈菌（Pucciniasorghi）是引起玉米锈病的一种真菌病原菌，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，从真菌分泌的效应蛋白，促进发病过程中，并识别宿主抗性蛋白的表征，仍然难以捉摸。这项研究将阐明玉米的一个重要防御机制，玉米是植物数量遗传学的模式物种，也是美国的头号作物，使用互补的方法，包括生物信息学，功能基因组学和先进的细胞生物学方法。由于过敏反应是在所有多细胞植物中发现的一般防御反应，因此这一发现将与改善其他重要作物物种，特别是其他禾本科植物有关。研究生、本科生和高中生将在怀俄明州大学和北卡罗来纳州州立大学接受作物研究的基本理解和植物-微生物相互作用中细胞生物学、生物化学和分子遗传学的尖端方法的培训。学生将参加这个项目作为兼职学生研究人员，并通过夏季研究计划在夏季更密集。计划与NCSU科学之家开展更多的外展活动，教育公众了解遗传学、植物育种、生物技术和相关的社会影响。该项目以本氏烟草为模型，阐明真菌病原体高粱柄锈菌和玉米相互作用的分子和细胞基础。玉米Rp 1-D基因编码NLR抗性蛋白，其赋予对由真菌高粱柄锈菌（Puccinia sorghi）引起的普通锈病的抗性。使用Rp 1-D基因的自激活衍生物的分子遗传学研究鉴定了几种宿主调节组分。然而，迄今为止，由Rp 1-D识别的病原体效应蛋白触发过敏反应程序性细胞死亡（HR-PCD）是难以捉摸的。本研究将1）鉴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中的基本生理变化，例如pH、活性氧产生和钙通量的变化，以及它们的亚细胞定位，和3）检查玉米HR关于这些生理变化和细胞器动力学，如小孢子的形成和细胞内的细胞器间通讯。最终，这项研究将表征与Rp 1-D相互作用的所有宿主和病原体衍生组分的物理相互作用，并且可能构成Rp 1-D介导的免疫信号复合物的细胞组分。这将导致对NLR介导的反应的控制的理解，这是玉米中唯一的，也是所有植物物种中最详细的。该奖项反映了NSF的法定使命，并被认为值得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来支持。

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.