Alternative Polyadenylation as a Major Regulatory Mechanism of Plant Innate Immunity

植物抗病(R)基因编码免疫受体，在病原微生物识别后介导抗病。它们的表达必须协调一致。研究人员先前在模式植物拟南芥中发现了一个控制两个r基因表达的新过程。该项目的主要目标是：(1)研究这种新机制在植物中用于调节其他r基因和其他防御基因的程度；(2)获得对这种新机制的详细了解。该研究结果可能对植物免疫和基因表达控制领域产生广泛影响。该项目还可能导致设计新的策略，以加强作物植物的疾病保护。该项目的一个重要组成部分是本科生的主要参与，主要来自少数民族。该项目将与首席研究员教授的生物化学和生物技术课程以及加州大学河滨分校植物细胞生物学中心正在进行的NSF-REU植物细胞生物学项目相关联。此外，该项目将为培养博士后学者和研究生提供一个强大的平台，为他们成为学术界或工业界的高级研究人员做好准备。2007年《美国竞争法》的目标是强调对研究的负责任和道德行为的认识，这是本项目的首要任务。选择性聚腺苷酸化正成为真核生物基因表达控制的主要机制。研究人员先前发现表观遗传标记H3K9me2控制拟南芥r基因RPP4和RPP7的聚腺苷化信号的差异使用，并调节由其编码的免疫受体介导的免疫水平。这一机制由表观遗传因子EDM2和一些新发现的调节因子控制。研究人员进一步发现，这种新机制对病原体识别有反应，并能动态调节RPP4和RPP7的表达。本项目的中心假设是，选择性聚腺苷酸化是控制诱导植物免疫反应的主要机制。要追求的两个具体目标是：1)防御诱导后替代聚腺苷酸化事件的全基因组谱分析；2)确定将选择性聚腺苷化与病原体感知和防御信号联系起来的调节因子。到目前为止，选择性聚腺苷酸化尚未被认为是控制植物免疫的主要机制。该项目将提供植物防御相关的选择性聚腺苷酸化的全基因组概述，并揭示这种调节过程的分子细节。

Plant disease resistance (R)-genes encode immune receptors that mediate disease resistance upon recognition of pathogenic microorganisms. Their expression has to be coordinated. The investigators previously identified a new process that controls the expression of two R-genes in the model plant Arabidopsis thaliana. The main goals of this project are (1) to examine extent to which this new mechanism is utilized in plants for the regulation of additional R-genes and other defense genes and (2) to gain detailed understanding of this new mechanism. Results from this study are likely to have a broad impact on the fields of plant immunity and gene expression control. This project may also lead to the design of new strategies for enhanced disease protection in crop plants. An important component of the project is major involvement of undergraduate students, mainly from minority groups. The project will be linked to classes on biochemistry and biotechnology taught by the Principal Investigator and the ongoing NSF-REU Plant Cell Biology program within the Center for Plant Cell Biology at UC-Riverside. In addition, the project will provide a strong platform for training of postdoctoral scholars and graduate students and prepare them for careers as senior researchers in academia or industry. The goals of the America COMPETES Act of 2007 that emphasize awareness of the responsible and ethical conduct of research are a top priority of this project.Alternative polyadenylation is emerging as a major mechanism of eukaryotic gene expression control. The investigators previously found the epigenetic mark H3K9me2 to control differential use of polyadenylation signals of the Arabidopsis R-genes RPP4 and RPP7 and to modulate levels of immunity mediated by their encoded immune receptors. This mechanism is controlled by the epigenetic factor EDM2 and several additional newly identified regulators. The investigators further showed this novel mechanism to be responsive to pathogen recognition and to dynamically adjust RPP4 and RPP7 expression. The central hypothesis of this project is that alternative polyadenylation is a major mechanism controlling inducible plant immune responses. The two specific aims that are to be pursued are: 1) Genome wide profiling of alternative polyadenylation events after defense induction; 2) Identify regulatory factors linking alternative polyadenylation to pathogen perception and defense signaling. Alternative polyadenylation has so far not been recognized as a major mechanism controlling plant immunity. This project will provide a genome-wide overview about defense-associated alternative polyadenylation in plants and uncover molecular details of this type of regulatory process.