DISSERTATION RESEARCH: The Genomic Basis of Adaptation in Experimentally Evolved Rhizobia

论文研究：实验进化根瘤菌适应的基因组基础

• 批准号: 0807793
• 负责人: Maureen Stanton
• 金额: $ 1.06万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-06-01 至 2009-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0807793&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Genomic; Basis; Adaptation

High-throughput sequencing technology will be used to identify mutations that influence the fitness of rhizobia that are symbiotic partners of legumes, providing a window into the ways that rhizobia adapt to the symbiotic lifestyle. Use of experimentally evolved populations of rhizobia derived from the model rhizobium 'Sinorhizobium meliloti' will enable direct measurement of the extent of host-symbiont conflict by asking whether mutations that confer higher rhizobia fitness have positive or negative effects on host performance. Identification of mutants will lead to development of testable mechanistic hypotheses and macro-evolutionary predictions, connecting laboratory results to natural populations.The symbiosis between legumes and rhizobia, bacteria that form root nodules and fix atmospheric nitrogen, is among the best model systems for understanding coevolution. While the interaction is widely assumed to be mutually beneficial, there is ongoing debate over the extent to which rhizobia can cheat their host plants by receiving plant resources without providing fixed nitrogen in return. The rhizobia-legume symbiosis is a key component of sustainable agriculture, as legumes can grow without oil-derived fertilizers and enrich soil fertility over the long-term when used in crop rotations. Legumes include the economically important crop species soy, alfalfa, pea, bean, chickpea, and peanut that provide plant-based protein for human and animal nutrition. Thus, increased understanding of the rhizobia genes implicated in this study may prove useful to agriculture for designing more efficient legume-rhizobia symbioses.

高通量测序技术将被用于识别影响作为豆科植物共生伙伴的根瘤菌适应性的突变，为根瘤菌适应共生生活方式提供一个窗口。使用来自模式根瘤菌‘Sinorhizobium Meliloti’的实验进化的根瘤菌种群，将能够通过询问赋予更高根瘤菌适合度的突变对宿主性能是否有积极或消极影响来直接测量宿主-共生体冲突的程度。突变体的识别将导致可测试的机制假说和宏观进化预测的发展，将实验室结果与自然种群联系起来。豆类与根瘤菌之间的共生是理解共同进化的最佳模式系统之一。根瘤菌是形成根瘤和固定大气氮的细菌。虽然这种相互作用被广泛认为是互惠互利的，但关于根瘤菌在多大程度上可以通过接受植物资源而不提供固定氮素来欺骗寄主植物的争论仍在继续。根瘤菌-豆类共生是可持续农业的关键组成部分，因为豆类可以在没有油基肥料的情况下生长，并在作物轮作中长期使用，从而丰富土壤肥力。豆类包括经济上重要的作物品种大豆、苜蓿、豌豆、豆类、鹰嘴豆和花生，它们为人类和动物提供以植物为基础的蛋白质。因此，对本研究中所涉及的根瘤菌基因的深入了解可能有助于农业设计更有效的豆科植物-根瘤菌共生体。