A resistance and susceptibility gene cluster in barley is targeted by diverse Pyrenophora teres f. teres effectors

大麦中的抗性和易感性基因簇是多种圆核菌 f 的靶标。

• 批准号: 1759030
• 负责人: Robert Brueggeman
• 金额: $ 10万
• 依托单位: North Dakota State University Fargo
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2020-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1759030&HistoricalAwards=false
• 关键词: resistance; susceptibility; gene; cluster; barley

The plant immune system recognizes pathogens early in the infection process, activating immune responses capable of arresting them before they colonize and establish themselves as a threat to viability. Pathogens that survive this first line of defense are met by a second line of defense that results in a higher amplitude programmed cell death response, which effectively sequesters some pathogens in foci of dead cells. However, in the case of necrotrophic pathogens, the class of plant pathogens that acquire nutrients from dead tissue, this defense response is hijacked and utilized by the pathogen to further disease proliferation, translating to crop failure. The project will fill knowledge gaps in the understanding of how plants perceive this important class of pathogens and how immunity responses result in a positive outcome for the plant host (disease resistance). Thus, the project will contribute to understanding of how plant immunity responses are effective at stopping the necrotrophic pathogens which is important as they are becoming well known for their roles in causing disease on important crops and are significantly contributing to world food security issues. The information generated will transect multiple pathosystems important to crop production through characterizing and defining the mechanism that regulates host signaling and immunity against diverse pathogens. The molecular genetic and genomic data generated and molecular tools developed, will broadly benefit the plant-microbe interactions scientific community as well as answer fundamental questions that will facilitate the deployment of genetic resistance in crops contributing to a more secure food supply. This research will also be used in cross-disciplinary training of high school, undergraduate, graduate, and post-graduate students in molecular genetics and molecular plant pathology from both the host and pathogen perspective. A collaborative outreach program developed through this grant will involve education of young Native American scientists in order to effectively recruit them into the scientific fields effectively broadening the participation of the most under represented group in the STEM fields.The overarching hypothesis is that early immunity responses are effective at stopping the necrotrophic pathogens, yet later elicited immunity responses result in programmed cell death that is effectively hijacked by the necrotophic specialists to complete their lifecycle, contributing to disease susceptibility. The two specific objectives to test this hypothesis focus on a comprehensive evaluation of the temporally and spatially distinct immunity and virulence responses from the host (barley) and pathogen (Pyrenophora teres f. teres), respectively. These aims will address fundamental questions: 1) is a diverse receptor-like protein targeted by multiple necrotrophic effectors to elicit necrotrophic effector triggered susceptibility (NETS); and 2) does a highly effective dominant resistance gene activate early defense responses, arresting the necrotrophic specialist before it colonizes and deploys its necrotrophic effector repertoire? The first component of the plant immune system investigated is a highly variable receptor-like protein, Spt1, which is targeted by multiple diverse necrotrophic effectors located throughout the genomes which evolved to incite disease. This receptor contains unprecedented variability at a localized region that correlates with specific susceptibilities, suggesting that the pathogen populations continually evolved to target this unknown domain and the host has been undergoing a high level of diversifying selection at this domain to evade pathogen virulence. The information gathered on the receptor and necrotrophic effectors will fill fundamental gaps in the knowledge of how necrotrophic specialists target the host and manipulate a weak link in its immune system to cause disease.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.

植物免疫系统在感染过程的早期识别病原体，激活免疫反应，能够在它们定殖并将自身确立为对生存能力的威胁之前将其捕获。在第一道防线中存活的病原体受到第二道防线的攻击，这导致更高幅度的程序性细胞死亡反应，这有效地将一些病原体隔离在死细胞的病灶中。然而，在坏死营养型病原体的情况下，这类植物病原体从死亡组织中获取营养，这种防御反应被病原体劫持和利用，以进一步疾病扩散，转化为作物歉收。该项目将填补知识空白，了解植物如何感知这类重要的病原体，以及免疫反应如何导致植物宿主的积极结果（抗病性）。因此，该项目将有助于了解植物免疫反应如何有效地阻止坏死性病原体，这一点很重要，因为它们在重要作物上引起疾病的作用越来越为人所知，并对世界粮食安全问题做出了重大贡献。所产生的信息将通过表征和定义调节宿主信号传导和对不同病原体的免疫力的机制来横切对作物生产重要的多种病理系统。产生的分子遗传和基因组数据以及开发的分子工具将广泛造福于植物-微生物相互作用科学界，并回答将促进作物遗传抗性部署的基本问题，从而有助于更安全的粮食供应。这项研究还将用于从宿主和病原体的角度对高中生、本科生、研究生和研究生进行分子遗传学和分子植物病理学的跨学科培训。通过这笔赠款开发的合作外展计划将涉及对年轻美洲原住民科学家的教育，以便有效地招募他们进入科学领域，有效地扩大STEM领域代表性最不足的群体的参与。首要假设是早期免疫反应可以有效地阻止坏死性病原体，然而，随后引发的免疫应答导致程序性细胞死亡，该程序性细胞死亡被坏死专家有效地劫持以完成它们的生命周期，从而导致疾病易感性。检验这一假设的两个具体目标集中在对来自宿主（大麦）和病原体（圆核腔菌（Pyrenophora teres f.圆），分别。这些目标将解决基本问题：1）是一种多样的受体样蛋白，由多种necrotrophic效应子靶向，以引发necrotrophic效应子触发的易感性（NETS）; 2）是否有一个高效的显性抗性基因激活早期防御反应，在necrotrophic专家定植和部署其necrotrophic效应子库之前逮捕它？研究的植物免疫系统的第一个组成部分是一种高度可变的受体样蛋白Spt 1，它被位于整个基因组中的多种不同的坏死营养效应子所靶向，这些效应子进化为煽动疾病。该受体在与特异性亲和性相关的局部区域包含前所未有的变异性，这表明病原体种群不断进化以靶向该未知结构域，并且宿主在该结构域经历了高水平的多样化选择以逃避病原体毒力。在受体和necrotrophic效应器上收集的信息将填补necrotrophic专家如何靶向宿主并操纵其免疫系统中的薄弱环节导致疾病的知识的根本空白。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智力价值和更广泛的影响审查标准进行评估来支持。