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，以确保提高作物生产力，同时将对环境的影响降至最低。优化与植物相关的微生物群落是一种可能的策略。乙烯气体是由植物产生的，并作为一种植物激素发挥作用，已知它会影响许多过程。初步研究结果表明，乙烯受体存在于细菌和植物中。这些细菌中的许多与植物有关，并且没有致病性，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改善植物与有益微生物之间关系所需的信息，以提高食品生产和安全性。这项研究还将通过扩大UT-诺克斯维尔大学本科生和研究生从事现代生物学研究的机会来增加教育基础设施。 该项目将验证植物产生的乙烯通过调节生物膜的形成和细菌对植物的附着来介导某些有益细菌在根际的建立的假设。初步数据表明，几个非致病性和非共生的，但可能有益的，变形菌的基因组编码同源植物乙烯受体，与固氮菌巴西同源物结合乙烯在体外。进一步的证据表明，细菌的乙烯感应调节生物膜的形成。乙烯信号和相关的反应在细菌中的分子机制将使用遗传和生物化学方法的组合，在遗传上顺从的细菌模型的特点。乙烯信号在调节有益细菌的根表面定殖中的作用将使用植物定殖测定结合模型和作物植物中乙烯信号的遗传或化学操纵来研究。还将测试植物和有益细菌之间的乙烯信号传导功能调节植物免疫反应的可能性。这项研究的结果将产生植物-细菌信号传导的新模型，从而产生创新策略，在根际设计有益的植物-微生物协会。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。

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.