FITTER · Friends with benefits – the role of endophytic bacteria in legume nodules containing nitrogen-fixing rhizobia

Friends with benefits – the role of endophytic bacteria in legume nodules containing nitrogen-fixing rhizobia

Modern agriculture faces the critical challenge of feeding a growing global population while protecting the environment and maintaining healthy soils for future generations. Conventional farming relies heavily on synthetic fertilizers, which cause water pollution and greenhouse gas emissions. Legumes (soybeans, clover, lucern, peas, beans), are important crops in agriculture due to their ability of biological nitrogen fixation. Biological nitrogen fixation is the conversion of atmospheric nitrogen into ammonia, a form of nitrogen that plants need for development and growth. Legumes form a mutualistic relationship with symbiotic bacteria, the rhizobia, which are housed in root nodules. Within those nodules, rhizobia use specialized enzymes to fix nitrogen, while the plant provides carbohydrates and a protected environment within the nodule. This relationship reduces the need for synthetic nitrogen fertilizers, making legumes essential for sustainable farming. Recent research reveals that root nodules harbour not only rhizobia but also diverse non-rhizobial endophytes (NRE), such as bacteria or fungi that may play important roles in plant health, stress tolerance and nutrient cycling. This raises intriguing questions about how these microbial communities contribute to the overall success of legumes and their ability to fix nitrogen. This project addressed this gap by investigating the diversity and functional roles of non-rhizobial endophytes in root nodules, shedding light on their contributions to legume health and productivity. Objectives of this Marie Skłodowska Curie Action (MSCA) were first to characterize the microbial communities within legume root nodules, with a particular focus on non-rhizobial bacteria (NRE). By employing advanced sequencing technologies, such as 16S rRNA gene sequencing and metagenomics we uncovered the diversity and composition of nodule bacterial communities of legume, clover and soybean grown in the field. Additionally, we investigated the rhizosphere, which is the soil surrounding plant roots, to understand the role of the rhizosphere microbiome as a source of NRE colonizing nodules. The second objective focused on uncovering the functional roles of the nodule bacterial community. Using a metagenomics approach, we aimed to identify the genes and metabolic pathways within nodule-associated bacteria. Additionally, we created a culture collection of rhizobia and NRE for future research. Finally, the third objective was to understand how environmental factors influence the diversity and functional roles of NAB within legume nodules. Factors such as soil type, nutrient availability, climate conditions, and agricultural practices are known to shape microbial communities in the rhizosphere, but their impact on nodule-associated bacteria remains poorly understood.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз