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Determining the role of defence systems in the evolution of the Azospirillum-wheat mutualism to enhance crop yields for sustainable agriculture

确定防御系统在固氮螺菌-小麦互利共生进化中的作用，以提高可持续农业的作物产量

基本信息

批准号：
BB/X010600/1
负责人：
Bridget Watson
金额：
$ 47.95万
依托单位：
UNIVERSITY OF EXETER
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2023
资助国家：
英国
起止时间：
2023 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FX010600%2F1
关键词：
Determining role defence systems evolution

项目摘要

Food producers face the global challenge of sustainably enhancing agricultural production. Increased production of nutrient dense crops is needed to feed the growing global population. However, chemical inputs must be reduced, and valuable resources, such as water, must be better managed to minimise adverse environmental impacts, including climate pollution, while restoring soil fertility. Microbes in the soil are essential for soil health and function. Plant growth promoting rhizobia (PGPR) grow in the rhizosphere and make nutrients available for plants, and produce molecules that stimulate root development, to enhance growth and resilience. In return, plants secrete molecules through their roots that are used by bacteria, hence forming a mutualistic relationship. The ubiquitous PGPR, Azospirillum, adapted to plant association by acquiring traits from soil microbes on mobile genetic elements (MGEs), which are pieces of DNA that move horizontally between bacteria. MGE acquisition can accelerate bacterial evolution, but they can also be costly to the host, so bacteria carry defence systems to limit MGE uptake. Azospirillum strains vary in the number and type of defence systems, but the role of defences in azospirilla genome evolution and crucially, how they affect plant growth promotion, has not been studied. My proposed research will use bioinformatics, molecular biology and plant experiments to determine how bacterial defence systems affect Azospirillum genome evolution. Since wheat is an important crop in the UK, I will isolate azospirilla from the rhizosphere of wheat grown in diverse UK soils. I will sequence the genomes and use bioinformatics pipelines and dedicated predictor tools to assess the abundance and diversity of MGEs present in my isolates and other related Azospirillum. To predict how defence systems may influence MGE uptake, I will quantify the number and types of defences present and perform statistical modelling to test for associations between defence system and MGE abundance. Systems associated with low MGE loads will be experimentally tested by creating mutants lacking the systems and I will perform infection assays using diverse MGEs and a range of delivery mechanisms to understand which types of MGEs are restricted by each system. It is not clear whether defences, by limiting MGE uptake, constrain the evolutionary potential of the host, or protect the genome against costly elements. To gain insight into the role systems play in azospirilla, and crucially, how the defence-MGE dynamics affect the plant growth promotion, I will perform in vitro assays for plant associated traits and plant growth experiments. I will compare the performance of the defence system knockout mutants, mutants that have acquired new MGEs and the ancestral strain. From these experiments, I will have a greater understanding of how defences shape azospirilla evolution.The proposed project will be carried out at the University of Exeter, where I will work with world-leading experts in microbial evolution, ecology and soil microbiology. Excellent mentorship, and valuable training in scientific skills and leadership, will ensure my success throughout the Fellowship and enable me to launch my independent research career. I will work with three project partners to ensure excellence in all aspects of this interdisciplinary project, including Mauchline, an expert in the wheat rhizosphere and the soil microbiome, Wisniewski-Dyé, who has vast experience in azospirilla manipulation and genomics, and Syngenta, who will perform further analysis and development of beneficial strains. Ending global hunger using sustainable agriculture is a major goal of the UN and the proposed project, to characterise azospirilla to be used for wheat growth promotion, will be a valuable contribution. Further, harnessing the soil microbiome will be a critical component of improving the success of crops, while protecting the environment for future generations.

粮食生产者面临着可持续提高农业生产的全球挑战。为了养活不断增长的全球人口，需要增加营养密集型作物的产量。然而，必须减少化学投入，必须更好地管理水等宝贵资源，以最大限度地减少对环境的不利影响，包括气候污染，同时恢复土壤肥力。土壤中的微生物对土壤的健康和功能至关重要。植物生长促进根瘤菌(PGPR)生长在根际，为植物提供养分，并产生刺激根发育的分子，以促进生长和恢复能力。反过来，植物通过它们的根部分泌供细菌使用的分子，从而形成一种互惠互利的关系。无处不在的PGPR，固氮螺菌，通过从土壤微生物那里获得移动遗传元件(MGES)上的特征来适应植物联想，MGES是在细菌之间水平移动的DNA片段。MGE的获得可以加速细菌的进化，但它们对宿主来说也可能是昂贵的，因此细菌携带防御系统来限制MGE的摄取。固氮螺菌菌株的防御系统的数量和类型各不相同，但防御系统在固氮螺菌基因组进化中的作用以及它们如何影响植物的生长促进还没有被研究过。我提议的研究将使用生物信息学、分子生物学和植物实验来确定细菌防御系统如何影响固氮螺菌基因组进化。由于小麦在英国是一种重要的农作物，我将从种植在英国不同土壤中的小麦根际中分离出固氮螺菌。我将对基因组进行测序，并使用生物信息学管道和专用预测工具来评估我的分离株和其他相关固氮螺菌中存在的MGES的丰度和多样性。为了预测防御系统可能如何影响MGE的摄取，我将量化现有防御系统的数量和类型，并进行统计建模，以测试防御系统和MGE丰度之间的关联。与低MGE负荷相关的系统将通过创建缺乏该系统的突变体进行实验测试，我将使用不同的MGES和一系列传递机制进行感染分析，以了解每个系统限制了哪些类型的MGE。目前尚不清楚的是，通过限制MGE的摄取，防御是限制了宿主的进化潜力，还是保护了基因组免受昂贵因素的影响。为了深入了解系统在固氮螺藻中所起的作用，以及至关重要的是，防御-MGE动态如何影响植物生长促进，我将进行植物相关性状的体外分析和植物生长实验。我将比较防御系统基因敲除突变体、获得新MGES的突变体和祖先菌株的性能。通过这些实验，我将更好地了解防御系统如何塑造固氮螺菌的进化。拟议的项目将在埃克塞特大学进行，在那里我将与微生物进化、生态学和土壤微生物学方面的世界领先专家合作。优秀的指导，以及宝贵的科学技能和领导力培训，将确保我在整个奖学金计划中取得成功，并使我能够开始我的独立研究生涯。我将与三个项目合作伙伴合作，以确保这一跨学科项目在所有方面的卓越表现，其中包括小麦根际和土壤微生物组专家Mauchline，在固氮螺菌操纵和基因组学方面拥有丰富经验的Wisniewski-Dyé，以及将对有益菌株进行进一步分析和开发的先正达。利用可持续农业消除全球饥饿是联合国的一个主要目标，拟议的项目将是一个有价值的贡献，该项目将描述用于促进小麦生长的固氮螺属植物。此外，利用土壤微生物群将是提高作物成功的关键组成部分，同时为子孙后代保护环境。