Role of MAPKKKa-Mediated Cell Death in Plant Disease Resistance and Susceptibility

MAPKKKA介导的细胞死亡在植物抗病和感病中的作用博伊斯·汤普森植物研究所的格雷戈里·马丁说，当受到致病微生物的攻击时，抗病和感病植物的叶片中都会发生局部的细胞死亡。在抗性植物中，细胞迅速死亡(6小时)被称为“过敏性反应”，被认为可以抑制病原体的进一步传播。在易受感染的植物中，寄主细胞死亡会持续很多天，表现为被称为“斑点”、“斑点”或“枯萎病”的疾病症状。寄主细胞死亡在多大程度上是抗病和易感的结果或原因，是植物病原菌相互作用研究中一个尚未解决的中心问题-部分原因是与病程相关的细胞死亡的分子机制在很大程度上是未知的。为了研究寄主细胞死亡，本项目将调查番茄对由紫丁香假单胞菌PV引起的细菌性斑点病的抗性和敏感性。番茄。这项工作的中心焦点将是编码MAPKKKa的基因。当该基因的表达受到干扰时，植物在抗病反应过程中不会发生细胞死亡。出乎意料的是，研究发现，MAPKKA的沉默也会干扰与细菌斑点病相关的细胞死亡。这些观察结果表明，寄主在促进疾病症状的形成中起着积极的作用，而MAPKKA是一个控制与抗性和敏感性相关的细胞死亡的分子开关。本项目旨在进一步确定MAPKKA在寄主细胞死亡中所起作用的分子机制。这项研究的目标是：1)鉴定和鉴定MAPKKA上游的寄主蛋白；2)调查寄主抗病和易感途径在多大程度上共享相同的信号成分；3)研究MAPKKA介导的细胞死亡在寄主对生物营养型和坏死型病原体的反应中的作用。这项研究将在三个领域产生更广泛的影响：1)本科生和高中生将作为博伊斯·汤普森研究所主持的NSF支持的植物基因组夏季研究计划的一部分进行培训；2)PI和他的实验室成员将继续参与几个外联计划，包括新视野高中计划；3)深入了解寄主细胞死亡在病原菌侵袭中的作用，将有助于开发新的疾病控制策略，从而减少对农药的依赖。

Role of MAPKKKa-mediated cell death in plant disease resistance and susceptibilityGregory Martin, Boyce Thompson Institute for Plant ResearchLocalized cell death occurs in leaves of both disease-resistant and disease-susceptible plants upon attack by disease-causing organisms. In resistant plants, rapid cell death (6 hrs) is referred to as the 'hypersensitive response' and is thought to inhibit further spread of the pathogen. In susceptible plants, host cell death occurs over the course of many days and manifests as disease symptoms referred to as 'specks', 'spots', or 'blights'. The extent to which host cell death is either a consequence or a cause of disease resistance and susceptibility is a central unresolved question in the study of plant pathogen interactions - in part because the molecular mechanisms underlying pathogenesis-related cell death are largely unknown. To investigate host cell death, this project will investigate both resistance and susceptibility in tomato to bacterial speck disease caused by Pseudomonas syringae pv. tomato. The central focus of the work will be a gene that encodes MAP kinase kinase kinase (MAPKKKa). When expression of this gene is interfered with the plant does not develop cell death during a disease-resistance response. Unexpectedly, it was found that silencing of MAPKKKa also interferes with cell death associated with bacterial speck disease. These observations indicate that the host plays an active role in promoting the formation of disease symptoms and that MAPKKKa acts as a molecular switch governing cell death associated with both resistance and susceptibility.This project aims to further define the molecular mechanisms underlying the role of MAPKKKa in host cell death. The objectives are: 1) Identify and characterize host proteins that function upstream of MAPKKKa; 2) Investigate the extent to which host disease resistance and susceptibility pathways share the same signaling components; and 3) Examine the role of MAPKKKa-mediated cell death in host responses to biotrophic and necrotrophic pathogens.There are three areas where this research will have broader impact: 1) Undergraduate students and high school students will be trained as part of the NSF-supported Plant Genomics Summer Research Program hosted by the Boyce Thompson Institute; 2) The PI and members of his lab will continue their involvement in several outreach programs including the New Visions high school program; and 3) Deeper understanding of the role of host cell death during pathogen attack will facilitate the development of new strategies of disease control thereby lessening dependence on pesticides.