Understanding the priming response in Systemic Acquired Resistance and Age-Related Resistance

了解系统获得性耐药和年龄相关耐药中的启动反应

• 批准号: RGPIN-2015-04319
• 负责人: Cameron, Robin
• 金额: $ 1.75万
• 依托单位: McMaster University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=680060
• 关键词: Understanding; priming; response; Systemic; Acquired

Plants possess a number of disease resistance pathways to combat microbial infections. Each year an estimated 40% of world food production is lost due to insects, weeds and disease despite resistant crop varieties and pesticide application. In view of these losses, the goal of my research team is to understand Systemic Acquired Resistance (SAR) and Age-related Resistance (ARR). Both SAR and ARR involve a priming stage in which an initial biological, chemical or developmental stimulus allows a plant to respond rapidly and effectively to subsequent pathogen infections. Understanding these priming mechanisms will provide insights for genetic and breeding strategies to allow crops to respond rapidly and effectively to disease. *** SAR is induced by an "immunizing" infection in one leaf producing SAR signals that move to uninfected leaves to prime plants to respond in a resistant manner to future infections. The outcome of SAR is similar to vaccination in mammals, however SAR is more effective as it protects plants against many different pathogens. We study a key player in SAR called DIR1. DIR1 encodes a lipid transfer protein (LTP) and in vitro it binds lipids in its hydrophobic binding cavity. We hypothesize that DIR1 binds a lipid and/or hydrophobic molecule and this complex moves to distant tissues to prime distant leaves to resist future pathogen infections. We discovered that DIR1 moves to distant tissue to initiate priming and created a number of tools to identify DIR1's binding partners. We are in position to understand how DIR1 and its binding partners are perceived in distant leaves to prepare plants to resist the next infection. This information will inform future manipulations to improve crop disease resistance.*** We also study ARR, in which a maturity-associated developmental trigger primes mature plants to respond in a highly resistant manner to normally virulent pathogens. We identified genes required for ARR including the flowering regulator SVP. In the interaction between plants and bacterial pathogens, many pathogens have evolved the ability to suppress plant defense. Our data support the hypothesis that SVP plays a role in preventing the bacterial pathogen, Pseudomonas syringae from suppressing the accumulation of anti-microbial salicylic acid (SA). By examining SA accumulation in wild type and svp mutants, combined with next generation RNA-sequencing, ChIP-qPCR, genetic suppressor screening and yeast-2-hybrid, we will discover how SVP controls ARR. Our research suggests that during ARR, plants use a novel mechanism to defend themselves by targeting and preventing the pathogen's ability to suppress defense. Understanding this novel defense mechanism will provide fundamental information enhancing our ability to manipulate this pathway to extend the highly effective ARR response to young crop plants.********

植物具有许多抗病途径来对抗微生物感染。每年，尽管作物品种和杀虫剂具有抗药性，但由于昆虫、杂草和疾病，估计仍有40%的世界粮食产量损失。鉴于这些损失，我的研究团队的目标是了解系统获得性抗性（SAR）和与植物相关的抗性（ARR）。SAR和ARR都涉及引发阶段，其中初始生物、化学或发育刺激允许植物对随后的病原体感染迅速有效地作出反应。了解这些引发机制将为遗传和育种策略提供见解，使作物能够快速有效地应对疾病。* SAR由一片叶子中的“免疫”感染诱导，产生SAR信号，该信号移动到未感染的叶子以引发植物以抗性方式对未来的感染作出反应。SAR的结果类似于哺乳动物中的疫苗接种，但SAR更有效，因为它保护植物免受许多不同病原体的侵害。我们研究了SAR中的一个关键角色，称为DIR 1。DIR 1编码脂质转移蛋白（LTP），并且在体外它在其疏水结合腔中结合脂质。我们假设DIR 1结合脂质和/或疏水分子，并且这种复合物移动到远处的组织以引发远处的叶子抵抗未来的病原体感染。我们发现，DIR 1移动到远处组织启动启动，并创建了一些工具来识别DIR 1的结合伴侣。我们能够理解DIR 1及其结合伙伴如何在远处的叶子中被感知，以使植物准备抵抗下一次感染。这一信息将为今后提高作物抗病性的操作提供信息。我们还研究了ARR，其中与成熟相关的发育触发器引发成熟植物以高度抗性的方式对通常有毒的病原体作出反应。我们确定了ARR所需的基因，包括开花调节因子SVP。在植物与细菌病原体的相互作用中，许多病原体进化出了抑制植物防御的能力。我们的数据支持这一假设，即SVP发挥作用，防止细菌病原体，假单胞菌抑制抗微生物水杨酸（SA）的积累。通过检测野生型和svp突变体中SA的积累，结合下一代RNA测序，ChIP-qPCR，遗传抑制基因筛选和酵母双杂交，我们将发现SVP如何控制ARR。我们的研究表明，在ARR过程中，植物使用一种新的机制来保护自己，通过靶向和阻止病原体抑制防御的能力。了解这种新的防御机制将提供基本信息，增强我们操纵这种途径的能力，以将高效的ARR反应扩展到年轻的作物植物。