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性和抗病性中的作用Gregory Martin，博伊斯汤普森植物研究所抗病和感病植物的叶片在受到致病生物的攻击时都会发生局部细胞死亡。 在抗性植物中，快速细胞死亡（6小时）被称为“过敏反应”，并被认为抑制病原体的进一步传播。 在易感植物中，宿主细胞死亡发生在许多天的过程中，并表现为被称为“斑点”、“斑点”或“枯萎”的疾病症状。 在植物病原体相互作用的研究中，宿主细胞死亡在多大程度上是抗病性和易感性的结果或原因是一个中心未解决的问题-部分原因是致病相关的细胞死亡的分子机制在很大程度上是未知的。 为了研究宿主细胞死亡，本项目将研究番茄对由假单胞菌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MAP激酶（MAPKKKa）的基因。 当该基因的表达受到干扰时，植物在抗病反应期间不会发生细胞死亡。 出乎意料的是，发现MAPKKKa的沉默也干扰与细菌斑点病相关的细胞死亡。 这些结果表明，宿主在促进疾病症状的形成中起着积极的作用，MAPKKKa作为一个分子开关，控制与抗性和易感性相关的细胞死亡。 目标是：1）鉴定和表征MAPKKKa上游功能的宿主蛋白; 2）研究宿主疾病抗性和易感性途径共享相同信号传导组分的程度; 3）研究MAPKKKa介导的细胞死亡在宿主对活体营养型和坏死营养型病原体的反应中的作用。1）本科生和高中生将接受培训，作为由博伊斯汤普森研究所主办的NSF支持的植物基因组学夏季研究计划的一部分; 2）PI及其实验室成员将继续参与几个外展计划，包括新视野高中计划; 3）深入了解病原体攻击过程中宿主细胞死亡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.