Investigating the link between microbiome composition and nitrogen fixation efficiency in the model legume Medicago truncatula

研究模型豆科植物蒺藜苜蓿的微生物组组成与固氮效率之间的联系

• 批准号: 2590894
• 金额: --
• 依托单位: University of Warwick
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2590894
• 关键词: Investigating; link; between; microbiome; composition

"Plants and microbes interact with one another in a multitude of ways, ranging from pathogenic to mutualistic. One of the most important plant-microbe interactions in agriculture is the legume-rhizobia co-symbiosis, a mutualistic relationship where the host provides photosynthates in the form of organic acids like succinate whilst the rhizobia provide fixated atmospheric nitrogen in the form of ammonia. Whilst the presence of rhizobia often increases the biomass of their host, not all rhizobia species are as efficient at producing fixated nitrogen and certain species and strains of rhizobia can be defined as high- or low-efficient symbionts. Rhizobia are certainly not the only group of bacteria that can influence plant phenotype and health. Soil contains a multitude of bacterial species that exist in the rhizosphere or even endosphere of plants, including legumes, that produce metabolites that impact plant physiology. This forms a feedback cycle where the compounds plants secrete into the soil impact the local microbial community which in turn influence the host. Recent work that forms the basis of this project has found that high-efficiency symbionts can influence the microbial community in the endosphere of the model legume Medicago truncatula. In this case, inoculation led to the reshaping of the microbiome - decreasing overall species diversity but increasing the diversity and abundance of bacteria belonging to the genus Actinobacteria. This shows that the process of nodulation can influence the microbiome of the host at at least one stage in this symbiotic interaction. This project will first aim to ask if the bacteria whose abundance changes as a result of rhizobia inoculation influence host biomass upon addition to the soil or root environment. The bacteria will be grouped based on their associated abundance increase with either high-efficiency rhizobia inoculation or low-efficiency/mock inoculation. Subsequent experiments will attempt to characterise the mechanisms behind why these changes in community composition and possible host biomass occur. Firstly, this will be carried out by investigating bacterial localisation within the host system using bacterial labelling with fluorophores. Secondly, 'omics characterisation will be used to investigate what processes are occurring on a molecular level that led to altered community dynamics as a result of nodulation. As part of this, there will be an attempt to generate a microbial library of the microbiome of Medicago truncatula which does not currently exist and would provide an important output for longer term study of the interaction between plant microbial communities, host plants and rhizobial symbionts. "

“植物和微生物以多种方式相互作用，从致病到互惠。农业中最重要的植物-微生物相互作用之一是豆科植物-根瘤菌共生，这是一种互惠关系，其中寄主以琥珀酸等有机酸的形式提供光合作用，而根瘤菌以氨的形式提供固定的大气氮。虽然根瘤菌的存在通常会增加其宿主的生物量，但并非所有根瘤菌种类都能有效地产生固定氮，某些根瘤菌种类和菌株可以被定义为高效或低效的共生体。根瘤菌当然不是唯一一组可以影响植物表型和健康的细菌。土壤中含有多种细菌，它们存在于植物的根际甚至内圈，包括豆科植物，它们产生影响植物生理的代谢物。这形成了一个反馈循环，植物分泌到土壤中的化合物影响当地的微生物群落，而微生物群落反过来又影响宿主。最近的工作构成了这个项目的基础，发现高效的共生体可以影响模式豆科植物紫花苜蓿（Medicago truncatula）内圈的微生物群落。在这种情况下，接种导致微生物组的重塑-总体物种多样性降低，但放线菌属细菌的多样性和丰度增加。这表明，结瘤过程可以影响宿主的微生物组至少一个阶段在这种共生相互作用。该项目将首先旨在询问由于接种根瘤菌而导致丰度变化的细菌是否会影响宿主生物量，以及土壤或根环境。细菌将根据其相关丰度增加进行分组，无论是高效根瘤菌接种还是低效/模拟接种。随后的实验将试图描述群落组成和可能的寄主生物量发生这些变化背后的机制。首先，这将通过使用荧光团细菌标记研究宿主系统内的细菌定位来进行。其次，组学表征将用于研究在分子水平上发生的过程，这些过程导致结瘤导致的群落动态改变。作为这项工作的一部分，我们将尝试建立一个目前尚不存在的苜蓿微生物群的微生物库，这将为长期研究植物微生物群落、寄主植物和根瘤菌共生体之间的相互作用提供重要的成果。”