Plasmid biology of Rhizobium leguminosarum

豆科根瘤菌的质粒生物学

• 批准号: 105660-2010
• 负责人: Hynes, Michael
• 金额: $ 2.91万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=521992
• 关键词: Plasmid; biology; Rhizobium; leguminosarum

Rhizobia are bacteria that are notable for their ability to form nitrogen-fixing nodules on the roots of legume plants, such as peas, beans, lentils and alfalfa. Their ability to allow these plants to grow without addition of synthetic fertilizers, whose production and application has a high cost in fossil fuel consumption, makes them extremely important in sustainable agriculture. Production of more efficient and more competitive rhizobial strains for use as legume inoculants is a major goal in biotechnology. However, the interactions of introduced rhizobial strains, and the potential for genetic transfer between strains in the environment, are not well understood. Rhizobia are unusual among bacteria in that they have large and complex genomes that usually consist of one chromosome and several very large extrachromosomal genetic elements known as plasmids. The plasmids tend to be very stable, and some of them exhibit properties intermediate between those expected of a plasmid and those of a chromosome. This proposal will focus on the plasmids of Rhizobium leguminosarum strains VF39 and 3841, both of which have six plasmids, with an emphasis on the genes that determine plasmid replication, stability, function in cells, and potential for transfer by conjugation between bacterial strains. The research builds on previous expertise in the lab for dealing with plasmids, and the availability of genome sequences for both strains. Two of the main themes will be 1) examining how plasmids ensure, by partitioning and other mechanisms, that they are stably maintained from one generation to the next, and 2) how a novel plasmid transfer system in VF39 functions to move other plasmids between strains. In addition, we plan to continue our ongoing work on the role of plasmid-encoded genes in survival of rhizobia in the soil and in competition for colonization and infection of host plants.

根瘤菌是以其在豆科植物如豌豆、菜豆、扁豆和苜蓿的根部形成固氮根瘤的能力而闻名的细菌。 它们能够让这些植物在不添加合成肥料的情况下生长，而合成肥料的生产和应用在化石燃料消耗方面具有很高的成本，这使得它们在可持续农业中非常重要。 生产更有效和更有竞争力的根瘤菌菌株用作豆类接种剂是生物技术的主要目标。 然而，引入的根瘤菌菌株的相互作用，并在环境中的菌株之间的遗传转移的潜力，没有得到很好的理解。 根瘤菌在细菌中是不寻常的，因为它们具有大而复杂的基因组，通常由一条染色体和几个非常大的染色体外遗传元件（称为质粒）组成。 质粒往往非常稳定，其中一些质粒的性质介于质粒和染色体之间。 该提案将集中在根瘤菌菌株VF 39和3841的质粒上，这两种菌株都有六个质粒，重点是决定质粒复制、稳定性、在细胞中的功能以及通过细菌菌株之间的接合转移的潜力的基因。 这项研究建立在实验室先前处理质粒的专业知识以及两种菌株基因组序列的可用性的基础上。两个主要主题将是1）研究质粒如何通过分配和其他机制确保它们从一代稳定地维持到下一代，以及2）VF 39中的新型质粒转移系统如何在菌株之间移动其他质粒。 此外，我们计划继续我们正在进行的工作中的作用，质粒编码的基因在土壤中的根瘤菌的生存和竞争的殖民化和宿主植物的感染。