Molecular interactions between rhizobacteria and wheat under water stress

超过30%的地球表面是干旱的，大多数气候变化模型预测未来干旱长度和严重程度的增加将对植物生命产生不利影响。植物通过培养根相关微生物来适应缺水，这些微生物增强了对环境胁迫的抵抗力。水分限制对植物及其相关微生物之间分子通讯和相互作用的影响仍然知之甚少。该项目将利用分析化学，生物信息学，遗传学和生理学方法相结合，研究干旱条件下根定殖细菌，合黄假单胞菌和小麦之间的互利相互作用。这项研究将产生新的见解，了解干燥土壤中的植物如何招募，塑造和操纵其相关的微生物以减轻干旱胁迫。该项目将培养研究生和一名博士后学者，他们将从事研究的各个方面。细菌代谢途径的分析将由本科生通过个人研究项目完成，并作为微生物遗传学和生态学课程的一部分。该项目小组将参与大学项目，并协调旨在招募代表性不足的群体进入科学领域并加强小学至大学科学教育的外联活动。这项研究对于利用有益的微生物群落来改善作物性能和补充植物育种工作至关重要。这项应用的首要目标是在分子水平上了解根际细菌如何在干燥土壤中保持生理活性和与植物宿主的紧密互利相互作用。植物可以被视为元生物或全生物，部分依赖于其微生物组的特定功能和性状。最近的研究强调了有益的根际细菌在植物耐受包括干旱在内的非生物胁迫的能力中的重要作用。然而，水分限制对根际植物-微生物通讯的影响几乎还没有被探索。该方法的重点是假单胞菌synxantha 2-79，一个模型的生物控制菌株，是自然适应小麦生长在西北太平洋干旱地区。具体目标是表征与水分胁迫相关的小麦根分泌物的变化，并将这些变化与2-79的生理学相关;使用RNA-seq鉴定2-79对水分胁迫条件的转录响应;并确定所选途径对2-79在水分亏缺条件下在根上持续的能力的贡献。预期的结果将有助于了解干旱土壤中的根沉积如何调节参与缓解干旱胁迫的细菌途径，并有助于选择特定类型的有益根际细菌。该项目还将为正在进行的实地研究提供重要的功能基因组学补充，这些研究旨在破译土壤水分对旱地小麦根际微生物组的影响。

Over 30% of the earth's surface is arid, and most climate change models predict future increases in drought length and severity that will adversely affect plant life. Plants adapt to water deprivation in part by fostering root-associated microorganisms that enhance resistance to environmental stresses. The impact of water limitation on molecular communication and the interactions between plants and their associated microbes remains poorly understood. This project will utilize a combination of analytical chemistry, bioinformatics, genetic, and physiological approaches to investigate the mutually beneficial interaction between the root-colonizing bacterium, Pseudomonas synxantha, and wheat under arid conditions. The research will yield new insights into how plants in dry soils recruit, shape, and manipulate their associated microbes to mitigate drought stress. This project will train graduate students and a postdoctoral scholar that will be engaged in all aspects of the research. The analysis of bacterial metabolic pathways will be done by undergraduates via individual research projects and as a part of microbial genetics and ecology classes. The project team will participate in university programs and coordinate outreach activities aimed at recruiting underrepresented groups into the sciences and strengthening science education at the elementary through college levels. This research is crucial for exploitation of beneficial microbial communities to improve crop performance and complement plant breeding efforts.An overarching goal of this application is to understand at the molecular level how root-colonizing (rhizosphere) bacteria maintain physiological activity and tight mutualistic interactions with their plant hosts in dry soils. Plants can be viewed as meta-organisms or holobionts that rely in part on their microbiome for specific functions and traits. Recent studies have highlighted the essential role of beneficial rhizobacteria in the ability of plants to tolerate abiotic stresses, including drought. However, the effect of water limitation on the plant-microbe communication in the rhizosphere remains virtually unexplored. The approach focuses on Pseudomonas synxantha 2-79, a model biocontrol strain that is naturally adapted to wheat grown in arid parts of the Pacific Northwest. The specific aims are to characterize the changes in wheat root exudates that are associated with water stress and to relate these changes to the physiology of 2-79; to identify transcriptional responses in 2-79 to water-stressed conditions using RNA-seq; and to define the contribution of selected pathways to the ability of 2-79 to persist on roots under conditions of water deficit. The expected results will help to understand how rhizodeposition in arid soils modulates bacterial pathways involved in the mitigation of drought stress and contributes to the selection of specific types of beneficial rhizobacteria. The project will also provide a crucial functional genomics complement to ongoing field studies aimed at deciphering the effect of soil moisture on the rhizosphere microbiome of dryland wheat.