Customized nitrogen-fixing microbiomes for environmental adaptation
Matteo Cordoba Agudelo
Collaborators: Miriam Gifford, Liam Walker, Gary Bending (all University of Warwick, UK)
Background: Legumes have evolved the ability to establish root symbioses with rhizobacteria capable of converting atmospheric nitrogen into organic forms and sharing this fixed nitrogen with their plant hosts. However, these symbioses are strongly affected by environmental stresses. Under stress conditions, legumes activate adaptive signalling pathways that interfere with rhizobial colonization and nodulation. In addition to N-fixing rhizobia, legumes also recruit other beneficial microbes that provide protection against environmental stresses and may interact with N-fixing bacteria to facilitate root nodulation. Previous work reported that the highly efficient N-fixer strain Sinorhizobium meliloti WSM1022 reshapes the root microbiome by recruiting a high-efficiency nitrogen-fixation mini-microbiome (hereafter referred to as the “N-biome”). Additionally, we identified a beneficial α-proteobacterium that colonizes host root tissues and enhances plant adaptation to environmental stress. We aim to establish this α-proteobacterium as a bio-protectant that supports N-biome symbiosis with Medicago truncatula under drought, a major climate-related stress.
Project: To evaluate the beneficial effects and robustness of the N-biome and the drought-resistance-inducing α-proteobacterium, we are conducting co-inoculation experiments under drought conditions using M. truncatula as a model. We assess plant performance through parameters such as growth, nodulation, and stress responses. In addition, we investigate the effects of the N-biome on root, rhizosphere, and nodule microbiomes under drought conditions, including changes in microbiome composition and function through transcriptomic analyses. Furthermore, using an integrative GWAS approach, we aim to identify plant genetic traits that facilitate symbiosis with the N-biome under drought stress.
Lab tools / techniques: SynComs, Metagenomics, Transcriptomics, Plant gene Expression GWAS
Relevant publications:
Baxter, L., Roy, P., Picot, E., Watts, J., Jones, A., Wilkinson, H., Schäfer, P., Gifford, M., & Lagunas, B. (2021). Comparative Genomics across Three Ensifer Species Using a New Complete Genome Sequence of the Medicago Symbiont Sinorhizobium (Ensifer) meliloti WSM1022. Microorganisms, 9(12), 2428.
Glaeser, S. P., Imani, J., Alabid, I., Guo, H., Kumar, N., Kämpfer, P., Hardt, M., Blom, J., Goesmann, A., Rothballer, M., Hartmann, A., & Kogel, K. H. (2016). Non-pathogenic Rhizobium radiobacter F4 deploys plant beneficial activity independent of its host Piriformospora indica. ISME Journal, 10(4), 871–884.
Lagunas, B., Richards, L., Sergaki, C., Burgess, J., Pardal, A. J., Hussain, R. M. F., Richmond, B. L., Baxter, L., Roy, P., Pakidi, A., Stovold, G., Vázquez, S., Ott, S., Schäfer, P., & Gifford, M. L. (2023). Rhizobial nitrogen fixation efficiency shapes endosphere bacterial communities and Medicago truncatula host growth. Microbiome 11, 146.