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，植物是复杂的微生物群落的宿主。竞争在这些社区中很普​​遍，因为多样的微生物争夺有限的营养供应，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克服宿主抵抗策略的潜在强大机制，对农业产生了严重影响。例如，在2001年，棉质细菌疫病（CBB），这种疾病有耐药品种，在美国南部重新出现。令人惊讶的是，这种疾病是在CBB耐药棉花上观察到的。仔细检查发现CBB病原体以及这些患病的棉花植物上的第二种细菌病原体。同时出现的假设是，两种细菌病原体正在协作以抑制宿主的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检验了假设。如果得到证实，这项研究将揭示一种新的病原体策略来克服宿主抗性的新领域，将来需要考虑。 Malvacearum（XCM）。 XCM和第二个病原体Pseudomonas syringae（PS）是从对XCM抗性的棉花植物共隔离的。因此，XCM和PS可能形成一种疾病复合物，该复合物抑制XCM触发的电阻。这项研究旨在揭示XCM和PS之间协作的假定机制。第一个目标将建立从经典植物病理技术改编的实验系统和测定，以仔细定义XCM和PS之间的潜在相互作用点。第二个目标将寻求XCM和PS之间协作的潜在分子机制。例如，PS可以使用其III型效应子的曲目来抑制通常由XCM触发的电阻响应。该假设将通过比较XCM，PS和与XCM和PS共接种后的植物防御基因表达来检验。 RNA测序和差异基因表达分析将揭示病原体和棉中触发的反应所采用的相关毒力机制。最终目标将通过在XCM和/或PS中构造遗传敲除以及进行致病性测定，直接测试特定细菌基因在任何相互作用中的作用。该项目通过同时考虑多种细菌植物病原体的效果来打破重要的新基础。了解定义这些复杂互动的规则必须满足人口日益增加和环境变化的农业需求。该奖项反映了NSF的法定任务，并且使用基金会的知识分子优点和更广泛的影响审查标准，被认为值得通过评估来获得支持。