From Symbiosis to Methanotrophy: Diverse Functions in Rhizobiales

自1995年以来，我们的NSERC发现计划一直围绕着紫花苜蓿的固氮共生体--紫花苜蓿根瘤菌展开。这是我们实验室所有其他工作的基础。有了这个建议，我们将继续在苜蓿上开展工作，研究根瘤侵染的遗传控制，以及主要的细胞内碳库PHB的代谢和氮代谢之间的调控联系。我们还将把我们的研究扩展到根瘤菌目的另一种成员，我们几年前开始研究的甲氧西林三孢子菌菌株OB3b。该菌株是一株甲烷菌，其利用碳的能力有限，仅限于甲烷和甲醇等C1化合物。我们将研究PHB在甲烷营养生长中的作用，并启动定义最小甲烷营养基因组的研究。在毛孢子菌中的工作将导致这种重要的甲烷营养菌基因组工程方法的发展和完善，为开发将甲烷转化为高价值生物产品的专门菌株铺平道路，并提供对甲烷营养的遗传和代谢需求的洞察。

Our NSERC Discovery program has revolved around Sinorhizobium meliloti, the nitrogen fixing symbiont of alfalfa, since 1995. This has served as the foundation for all other work in our lab. With this proposal, we are continuing to work in S. meliloti, investigating genetic control of root nodule infection, and also regulatory links between metabolism of PHB, which is the major intracellular carbon store, and nitrogen metabolism. We will also extend our research to another member of the order Rhizobiales, Methylosinus trichosporium strain OB3b, which we started working on a few years ago. This strain is a methanotroph, which has a restricted carbon utilization capability, limited to C1 compounds such as methane and methanol. We will investigate the role of PHB in methanotrophic growth, and initiate research towards defining the minimal methanotrophic genome. The work in M. trichosporium will result in the development and refinement of genome engineering methods for this important methanotroph, pave the way for development of specialized strains for the conversion of methane to high value bioproducts, and provide insight into the genetic and metabolic requirements for methanotrophy.