Differential regulation of plant innate immunity

描述（由申请人提供）：植物和动物依靠先天免疫通过模式识别受体（PRRs）检测病原体相关分子模式（PAMPs）来预防潜在感染。在植物中，PAMP通过细胞表面PRRs和mount PAMP触发免疫（PTI）感知。成功的病原体能够通过产生毒力效应物来抑制PTI，而毒力效应物反过来又被植物细胞内PRRs识别，从而启动效应触发免疫（effector-triggered immunity， ETI）。这种复杂的宿主-微生物相互作用与广泛的环境因素错综复杂地交织在一起。例如，我们发现环境温度波动以不同的方式调节PTI和ETI。我们已经开发了一种拟南芥细胞系统，用于表达ETI的单个病原体效应物或用纯化的PAMPs治疗PTI细胞。结合拟南芥丰富的遗传和基因组资源，这种同步和自主的植物细胞-单病原体信号系统为解剖ETI和PTI信号事件的复杂调控提供了重要的希望。我们的初步数据强烈表明，存在差异的早期信号机制，在植物先天免疫的两个分支。特别是，我们发现编码钙依赖性蛋白激酶（CDPKs）的大基因家族的特定成员在ETI的钙信号转导中起关键作用。我们提出的研究将采用多方面的方法来进一步了解植物ETI和PTI的信号机制。本应用的具体目的是：1)破译ETI和PTI中不同的和趋同的基因调控；2)阐明CDPKs在ETI信号传导中的作用；3)剖析环境温度对先天免疫的调节。植物PTI和ETI分别与哺乳动物的“toll样受体”和“nod样受体”先天免疫信号通路最为相似。因此，我们的研究将有助于对先天免疫的全面了解，提高我们预防和控制传染病的能力。

DESCRIPTION (provided by applicant): Plants and animals rely on innate immunity to prevent potential infections by detection of pathogen-associated molecular patterns (PAMPs) through pattern recognition receptors (PRRs). In plants, PAMPs are perceived by cell-surface PRRs and mount PAMP- triggered immunity (PTI). Successful pathogens are able to suppress PTI by producing virulence effectors, which, in turn, are recognized by plant intracellular PRRs to initiate effector-triggered immunity (ETI). This complex host-microbe interaction is intricately intertwined with a wide range of environmental factors. For example, we found that the ambient temperature fluctuation regulates PTI and ETI in a distinct manner. We have developed an Arabidopsis cell system to express individual pathogen effectors for ETI or treat cells with purified PAMPs for PTI. In combination with enriched genetic and genomic resources in Arabidopsis, this synchronized and autonomous plant cell-single pathogen signal system holds significant promise for dissecting the complex regulation of signaling events in ETI and PTI. Our preliminary data strongly suggest the existence of differential early signaling mechanisms underlying two branches of plant innate immunity. In particular, we found that the specific members of a large gene family encoding calcium-dependent protein kinases (CDPKs) play pivotal roles in transducing calcium signature in ETI. Our proposed research will employ a multifaceted approach to further understand the signaling mechanisms underlying plant ETI and PTI. The Specific Aims for this application are the following: 1) Decipher the distinct and convergent gene regulation in ETI and PTI; 2) Elucidate the functions of CDPKs in ETI signaling; 3) Dissect the ambient temperature regulation of innate immunity. Plant PTI and ETI are most similar to "Toll-like receptor" and "NOD-like receptor" innate immune signaling pathways in mammals respectively. Thus, our research will contribute to a general understanding of innate immunity and improve our ability to prevent and control infectious diseases. PUBLIC HEALTH RELEVANCE: Understanding the intricately intertwined signal transduction networks acting downstream of various host immune sensors could provide novel avenues to prevent and control infectious diseases. Given that plant cell-surface and intracellular immune sensors are most similar to "Toll-like receptor" and "NOD-like receptor" in mammals respectively, our research will have broad impact on the understanding of signaling mechanisms of animal innate immunity.