CAN BACTERIAL PILI AND PLANT HOMOLOGS TO MAMMALIAN PILUS-BINDING PROTEINS BE THE KEY AND LOCK TO SYMBIOTIC NITROGEN FIXATION?-USING NSF-FUNDED GENOME PROJECTS TO FIND NOVEL GENES

细菌菌毛和植物与哺乳动物菌毛结合蛋白的同源物能否成为共生固氮的关键和锁？——利用 NSF 资助的基因组项目寻找新基因

• 批准号: 0537497
• 负责人: Ann Hirsch
• 金额: --
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0537497&HistoricalAwards=false
• 关键词: BACTERIAL; PILI; PLANT; HOMOLOGS; MAMMALIAN

The goal of this project is to better understand attachment and infection thread formation of bacteria during the nitrogen-fixing symbiosis that occurs with legumes. The nitrogen-fixing symbiosis between bacteria of the Rhizobiaceae and legume plants involves a constant dialogue between partners that results in bacterial attachment to plant roots, the formation of infection threads through which the bacteria enter the root, and the development of the nodule on plant roots, in which the bacteria convert atmospheric nitrogen into ammonia that is readily assimilated by the plant. Nod factor, a bacterial signal molecule, is critical for infection thread formation and nodule development. However, some legumes differ from this paradigm. They form nitrogen-fixing associations in the absence of nodules and with bacteria other than rhizobia. Infection thread formation and invasion does not require Nod factor suggesting that other bacterial factors are important for infection thread formation and that fewer steps are required for establishment of the symbiosis. Intellectual Merit: Most bacterial-eukaryotic cell interactions involve host receptor-protein-pili interactions followed by endocytosis. This type of protein-protein interaction could mediate the non-nodulating legume symbiosis. This project will use biochemical, genetic and genomic approaches to assess the role of bacterial pili and to look for putative plant pili-binding proteins in both nodulating and non-nodulating legume symbioses. To elucidate the role of pili in attachment and infection thread formation, candidate genes involved in pili formation will be identified in rhizobial and non-rhizobial species and mutants generated to assess how the symbiosis is affected. Pili-binding proteins also will be identified in model legumes and gene disruption techniques will be employed to determine their requirement for establishment of the association.Broader impacts: The results of this study will provide a more concrete analysis of the earliest stages of the nitrogen-fixing symbiosis in a non-nodulating legume, and will be prepared for publication in peer-reviewed journals as well as being of topic of discussion in Dr. Hirsch's undergraduate course: Chemical Communication between Plants and Other Organisms. A postdoctoral associate will be directly involved in this research as well as a Ph.D. student. In addition, a Masters degree student will be helping the postdoctoral associate; both are female Asian-Americans.

本项目的目标是更好地了解豆科植物固氮共生过程中细菌的附着和感染线的形成。根瘤菌科细菌和豆科植物之间的固氮共生关系涉及伴侣之间的持续对话，其导致细菌附着于植物根部，形成细菌进入根部的感染线，以及植物根部上的根瘤的发育，其中细菌将大气氮转化为易于被植物同化的氨。结瘤因子是一种细菌信号分子，对侵染丝的形成和根瘤的发育至关重要。然而，一些豆类与这种模式不同。它们在没有根瘤的情况下与根瘤菌以外的细菌形成固氮联合体。侵染线的形成和侵入不需要结瘤因子，这表明其他细菌因子对侵染线的形成也很重要，并且建立共生关系所需的步骤较少。知识点：大多数细菌-真核细胞相互作用涉及宿主受体-蛋白质-皮利相互作用，随后是内吞作用。这种类型的蛋白质-蛋白质相互作用可以介导非共生豆科植物共生。 该项目将使用生物化学、遗传学和基因组方法来评估细菌皮利的作用，并在结瘤和非结瘤豆类共生体中寻找推定的植物皮利结合蛋白。为了阐明皮利在附着和感染线形成中的作用，将在根瘤菌和非根瘤菌物种和产生的突变体中鉴定参与皮利形成的候选基因，以评估共生如何受到影响。还将在模式豆类中鉴定菌毛结合蛋白，并将采用基因破坏技术来确定建立这种关联所需的菌毛结合蛋白。这项研究的结果将提供一个更具体的分析的最早阶段的固氮共生在非豆科植物，并将准备在同行评议的期刊上发表，以及赫希博士的本科课程讨论的主题：植物和其他生物体之间的化学通讯。 一名博士后助理将直接参与这项研究，以及一名博士。学生. 此外，一名硕士生将帮助博士后助理;两人都是亚裔女性。