Gene networks of Sinorhizobium meliloti

豆类，如豆类(如鹰嘴豆、小扁豆)和大豆，是加拿大的主要农作物。加拿大是扁豆和豌豆产量的世界领先者，而豆类和大豆占加拿大农产品出口价值的20%。关键是要发展可持续的农业做法，最大限度地提高豆类作物产量，同时最大限度地减少现代农业的成本和对环境的影响。这些需求可以通过改善豆类与它们的细菌伙伴--根瘤菌之间的关系来解决。这些土壤细菌与豆类进入内生共生关系，在此期间它们将氮气转化为铵，从而使植物在没有氮肥的缺氮土壤中茁壮成长。优化这一过程将提高作物产量，同时减少有毒化肥的使用。在轮作期间，根瘤菌的固氮也在改善土壤质量方面发挥着重要作用。我研究的长期目标是了解根瘤菌如何在与豆类的共生中固定氮，以便设计出具有改善植物生长促进能力的菌株。为了实现这一目标，首先需要更好地了解根瘤菌基因组的功能，以及哪些生物学活动决定了共生相互作用的有效性。我们将：i)使用最先进的方法以高通量的方式揭示根瘤菌基因的功能，ii)测试胁迫耐受性在优化根瘤菌与豆类相互作用的能力中的作用，以及iii)建立和使用新的工具来研究基因在与豆类相互作用中的作用。我们将以多学科的方法完成这些任务，整合分子遗传学、功能基因组学、微生物生理学、植物-微生物相互作用、比较基因组学和电子代谢模型的现有方法。通过这项研究计划，我们将产生根瘤菌-豆类共生的新知识，这些知识最终转化为应用成果将造福于加拿大豆类种植者和全球环境。此外，该研究项目的多学科性质将为HQP的广泛培训提供一个出色的环境，为他们提供新兴技术和专业能力方面的专业知识。对基因功能缺乏功能的了解并不是根瘤菌所特有的，而是原核(和真核)基因组学中的一个持久问题。这些功能知识的空白可能会削弱合成生物学家设计具有改进表型的细菌的能力。这项研究计划将在苜蓿中华根瘤菌基因组的功能注释方面取得重大进展，中华根瘤菌是一种模式甲型蛋白细菌，与许多与生物技术应用相关的细菌密切相关，如生物修复和生物燃料生产。因此，我们的研究也将使加拿大萌芽中的生物技术部门受益。

Legumes, like pulses (e.g., chickpeas, lentils) and soybean, are major crops in Canada. Canada is the world-leader in production of lentils and peas, while pulses and soybean account for 20% the value of Canada's agricultural commodity exports. It is crucial to develop sustainable agricultural practices maximizing legume crop yields while minimizing the costs and environmental impacts of modern farming. These needs can be addressed by improving the relationship between legumes and their bacterial partners, the rhizobia. These soil bacteria enter into endosymbiotic relationships with legumes, during which they convert N2 gas into ammonium thereby allowing the plants to thrive in nitrogen-deficient soils without nitrogen fertilizers. Optimizing this process would increase crop yield while reducing the use of toxic fertilizers. Nitrogen fixation by rhizobia also plays an important role in improving soil quality during crop rotations. The long-term goal of my research is to understand how rhizobia fix nitrogen in symbiosis with legumes in order to engineer strains with improved plant growth promoting abilities. To achieve this goal, it is necessary to first develop a better functional understanding of the genome of rhizobia and which biological activities determine the effectiveness of the symbiotic interaction. We will: i) use state-of-the-art methods to uncover the functions of rhizobium genes in a high-throughput manner, ii) test the role of stress tolerance in optimizing the ability of rhizobia to interact with legumes, and iii) build and use novel tools to study the roles of genes throughout the interaction with legumes. We will accomplish these tasks with a multi-disciplinary approach integrating current methodologies in molecular genetics, functional genomics, microbial physiology, plant-microbe interactions, comparative genomics, and in silico metabolic modelling. Through this research program, we will generate new knowledge of rhizobium - legume symbioses, whose eventual translation into applied outcomes will benefit Canadian legume farmers and the global environment. Additionally, the multi-disciplinary nature of the research program will provide an outstanding environment for the broad training of HQP, providing them with expertise in emerging technologies and professional competencies. A poor functional understanding of gene function is not specific to rhizobia but is an enduring issue within prokaryotic (and eukaryotic) genomics. These functional knowledge gaps can impair the ability of synthetic biologists to engineer bacteria with improved phenotypes. This research program will provide a significant advance in the functional annotation of the genome of Sinorhizobium meliloti, a model Alphaproteobacterium that is closely related to numerous bacteria relevant to biotechnological applications such as bioremediation and biofuel production. As such, our research will also benefit Canada's budding biotechnology sector.