Ethylene Cross-Kingdom Signaling In Beneficial Plant-Microbe Associations

随着人口的增加，未来的粮食安全在很大程度上取决于可持续的农业做法，以确保在对环境影响最小的情况下提高作物生产率。优化与植物相关的微生物群落是一种可能的战略。乙烯气体是由植物产生的，它的功能是一种植物激素，众所周知，它会影响许多过程。初步研究结果表明，细菌和植物中都存在乙烯受体。这些细菌中的许多都与植物有关，没有一种是致病的，因此植物产生的乙烯可能起到调节有益的植物-微生物相互作用的作用。这项关于乙烯在植物-微生物相互作用中作用的研究结果将提供必要的信息，以改善植物与有益微生物之间的联系，以提高粮食生产和安全。这项研究还将扩大德克萨斯大学诺克斯维尔分校的本科生和研究生从事现代生物学研究的机会，从而增加教育基础设施。该项目将检验这样一个假设，即植物产生的乙烯通过调节生物膜的形成和细菌在植物上的附着来中介一些有益细菌在根际的建立。初步数据表明，几种非致病和非共生但具有潜在益处的变形杆菌的基因组编码植物乙烯受体的同源物，而巴西固氮螺杆菌的同源物在体外与乙烯结合。进一步的证据表明，细菌对乙烯的感知调节了生物膜的形成。细菌中乙烯信号和相关反应的分子机制将在遗传服从细菌模型中使用遗传和生化方法相结合的方法来表征。乙烯信号在调控有益细菌根表面定植中的作用将通过植物定殖分析结合乙烯信号在模式植物和作物中的遗传或化学操作来研究。植物和有益细菌之间的乙烯信号功能调节植物免疫反应的可能性也将得到测试。拟议的研究结果将产生植物-细菌信号的新模型，这些模型可以产生创新的战略，以在根际设计有益的植物-微生物协会。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With an increasing human population, future food security largely depends on sustainable agricultural practices that ensure elevated crop productivity with minimal environmental impact. Optimizing the microbial community that associates with plants is a possible strategy that is being pursued. Ethylene gas is produced by plants and functions as a plant hormone where it is known to affect many processes. Preliminary findings demonstrate that ethylene receptors are present in bacteria as well as plants. Many of these bacteria associate with plants and with none being pathogenic, it follows that ethylene produced by plants may function to regulate beneficial plant-microbe interactions. Results from this research on the role of ethylene in plant-microbe interactions will provide information needed to improve associations between plants and beneficial microbes to enhance food production and security. The research will also increase educational infrastructure by broadening opportunities for undergraduate and graduate students at the UT-Knoxville to engage in modern biological research. The project will test the hypothesis that ethylene produced by plants mediates the establishment of some beneficial bacteria in the rhizosphere via regulating biofilm formation and attachment of the bacteria to the plants. Preliminary data demonstrate that the genomes of several non-pathogenic and non-symbiotic, but potentially beneficial, proteobacteria encode homologs to plant ethylene receptors, with the Azospirillum brasilense homolog binding ethylene in vitro. Further evidence suggests that ethylene sensing by the bacteria modulates biofilm formation. The molecular mechanism of ethylene signaling and associated responses in bacteria will be characterized using a combination of genetic and biochemical approaches in genetically amenable bacterial models. The role of ethylene signaling in modulating root surface colonization by beneficial bacteria will be studied using plant colonization assays combined with genetic or chemical manipulation of ethylene signaling in model and crop plants. The possibility that ethylene signaling between plant and beneficial bacteria functions to modulate plant immune responses will also be tested. Results from the proposed research will generate novel models for plant-bacteria signaling that could yield innovative strategies to engineer beneficial plant-microbe associations in the rhizosphere.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.