Rhizosphere bacteria promote sustainable crop growth

可持续农业受益于自然存在的土壤栖息微生物提供的生态系统服务，植物将这些微生物吸收到根际，形成植物根系微生物群。微生物影响植物生长和资源利用效率，可以改善植物营养、健康和作物产量，同时尽量减少肥料和农用化学品的使用。主要参与者是荧光假单胞菌，这是一种普遍存在的、多样化的、可培养的根际细菌群。有益性状包括植物激素效应、营养增强和对病原体的保护。该项目旨在确定荧光假单胞菌拥有的特定基因在多大程度上可以预测它们对植物生长的影响，以及是否可以通过引入接种剂来管理土壤生态系统，作为单个菌株或组合。洛桑研究所收集了从小麦根际分离的遗传上不同的荧光假单孢菌；使用标准生物信息学和分子工具筛选20种基因编码有益和有害性状的基因组序列。具有不同性状的分离株将（单独或组合）应用于作物植物，以确定对生长、恢复力、资源利用效率的影响，以及细菌相互竞争的能力和本地土壤细菌定殖植物根系和在土壤中生存的能力。项目中需要检验的假设：植物要么差异性地选择具有有益性状的根际微生物，要么这个过程是随机的，取决于散装土壤中细菌的数量和多样性。引入有益的个体分离物或组合物可以促进植物生长，并允许更有效地利用肥料3。作物水分状况影响微生物种群及其与植物的相互作用

Sustainable agriculture benefits from ecosystem services provided by naturally occurring soil dwelling microbes that plants recruit into the rhizosphere to create the plant root microbiome. Microbes influence plant growth and resource use efficiency and can improve plant nutrition, health and crop yields whilst minimizing fertilizer and agrochemical use. Key players are the fluorescent pseudomonads, a ubiquitous, diverse and culturable group of rhizosphere bacteria. Beneficial traits include phytohormone effects, nutritional enhancement and protection from pathogens. This project aims to establish the extent to which possession of particular genes by Pseudomonas fluorescens predicts their effects on plant growth and whether the soil ecosystem can be managed by introducing inoculants, as single strains or assemblages.Rothamsted has a collection of genetically-distinct P. fluorescens isolates from the wheat rhizosphere; genomic sequences are available for 20 which will be screened for genes encoding beneficial and deleterious traits, using standard bioinformatics and molecular tools. Isolates with contrasting traits will be applied (both singly and in assemblages) to crop plants to determine effects on growth, resilience, resource use efficiency, and the ability of the bacteria to compete with each other and indigenous soil bacteria to colonize plant roots and survive in soil.Hypotheses to be tested in the project:1. Plants either differentially select rhizosphere microorganisms with beneficial traits, or the process is stochastic and depends on the numbers and diversity of bacteria in the bulk soil 2. Introducing beneficial individual isolates or assemblages can enhance plant growth and allow more efficient use of fertilizers 3. Crop water status affects microbial populations and their interactions with plants