EAGER: Characterization of a putative Xanthomonas-Pseudomonas disease complex of Cotton

EAGER：棉花黄单胞菌-假单胞菌病复合体的表征

• 批准号: 1928344
• 负责人: Rebecca Bart
• 金额: $ 30万
• 依托单位: Donald Danforth Plant Science Center
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1928344&HistoricalAwards=false
• 关键词: EAGER; Characterization; putative; Xanthomonas; Pseudomonas

In agricultural settings, plants are hosts to complex microbial communities. Competition is common within these communities as diverse microbes compete for a limited supply of nutrients, but there are also opportunities for collaboration. In the context of the "arms race" that defines host-pathogen interactions, pathogen-pathogen collaboration represents a potentially powerful mechanism for disease organisms to overcome host resistance strategies, with severe implications for agriculture. As an example, in 2001, cotton bacterial blight (CBB), a disease for which there are resistant cotton varieties, re-emerged across the southern USA. Surprisingly, the disease was observed on CBB-resistant cotton plants. Closer examination revealed the CBB pathogen as well as a second bacterial pathogen on these diseased cotton plants. The co-occurrence led to the hypothesis that the two bacterial pathogens are collaborating to suppress host resistance responses and cause disease. This project tests that hypothesis using genomics and molecular biology approaches. If confirmed, this research will have revealed a new frontier of pathogen strategies to overcome host resistance that will need to be considered in the future.CBB is caused by Xanthomonas citri pv. malvacearum (Xcm). Xcm and a second pathogen, Pseudomonas syringae (Ps), were co-isolated from cotton plants that are resistant to Xcm. Xcm and Ps may, therefore, be forming a disease complex that suppresses the resistance triggered by Xcm. This research aims to reveal the putative mechanism(s) of collaboration between Xcm and Ps. The first aim will establish experimental systems and assays, adapted from classic plant pathology techniques, to carefully define points of potential interaction between Xcm and Ps. The second aim will seek potential molecular mechanisms of collaboration between Xcm and Ps. For example, Ps may use its repertoire of type III effectors to repress the resistance response normally triggered by Xcm. This hypothesis will be tested by comparing plant defense gene expression after inoculation with Xcm, Ps and co-inoculation with Xcm and Ps. RNA sequencing and differential gene expression analyses will reveal the relevant virulence mechanisms employed by both pathogens and the response triggered within cotton. The final aim will directly test the roles of specific bacterial genes in any interaction by constructing genetic knockouts in Xcm and/or Ps and conducting pathogenicity assays. This project breaks important new ground by considering the effect of multiple bacterial plant pathogens attacking the same host simultaneously. Understanding the rules that define these complex interactions is required to meet the agricultural needs of an increasing population and changing environment.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.

在农业环境中，植物是复杂微生物群落的宿主。竞争在这些社区中很常见，因为不同的微生物竞争有限的营养供应，但也有合作的机会。在定义宿主-病原体相互作用的“军备竞赛”的背景下，病原体-病原体协作代表了疾病生物体克服宿主抗性策略的潜在强大机制，对农业具有严重影响。例如，在2001年，棉花细菌性枯萎病（CBB），一种有抗性棉花品种的疾病，在美国南部重新出现。令人惊讶的是，在CBB抗性棉花植物上观察到该疾病。更仔细的检查发现CBB病原体以及这些患病棉花植株上的第二种细菌病原体。同时发生导致了这样的假设，即两种细菌病原体正在合作抑制宿主抗性反应并引起疾病。该项目使用基因组学和分子生物学方法来验证这一假设。如果得到证实，这项研究将揭示一个新的前沿的病原体战略，以克服宿主的抗性，将需要在未来考虑。锦葵属（Malvacearum）。Xcm和第二种病原体，假单胞菌（PS），共分离自棉花植物是Xcm的抗性。因此，Xcm和Ps可能形成一种疾病复合体，抑制Xcm引发的耐药性。本研究旨在揭示Xcm和Ps之间协同作用的可能机制。第一个目标将建立实验系统和测定，从经典的植物病理学技术，仔细定义XCM和Ps之间的潜在相互作用点。第二个目标将寻求Xcm和Ps之间合作的潜在分子机制。例如，Ps可以使用其III型效应子的库来抑制通常由Xcm触发的抗性反应。将通过比较接种Xcm、Ps和共接种Xcm和Ps后的植物防御基因表达来检验这一假设。RNA测序和差异基因表达分析将揭示这两种病原体的相关毒力机制和棉花内引发的反应。最终的目标是通过构建Xcm和/或Ps中的基因敲除并进行致病性测定来直接测试特定细菌基因在任何相互作用中的作用。该项目通过考虑多种细菌性植物病原体同时攻击同一宿主的影响，开辟了重要的新领域。了解这些复杂的相互作用的定义规则是满足不断增长的人口和不断变化的环境的农业需求所必需的。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。