Root-microbe interactions in Rhizobium-legume symbioses.
Nitrogen fixing Rhizobium-legume symbioses are of extraordinary agricultural importance, able to largely free legume crops (including soy, pea and alfalfa) from the need for synthetic nitrogenous fertilisers. This is important, as man-made fertilisers are both expensive and polluting, propagating cycles of poverty in developing nations and environmental degradation in the developed world.
Symbiosis formation occurs as bacteria and plant roots interact using a detailed spatio-temporal crosstalk mechanism. Following this, bacteria penetrate plant roots and enter the plant-derived nodule structures, where they fix nitrogen in exchange for organic acids. Whilst many stages of symbiosis formation are well characterised, the initial physical interaction stage of roots and microbes, and the mechanisms underlying this, remain elusive.
My work in Oxford uses a range of novel imaging techniques and molecular approaches to uncover the biology of these interactions. High resolution luminescence and fluorescence-based technologies are allowing the characterisation of root-microbe interactions and the elucidation of their molecular mechanisms. A detailed genetic hierarchy gives rise to the overall phenotype of plant root attachment and colonisation, and here these hierarchies are being dissected for the first time.
Better characterisation of Rhizobium-legume symbioses has enormous potential for ensuring global food security, as a long-term goal of research in this field is the transfer of this phenotype to major cereal crops. Achieving this could precipitate a second, environmentally friendly ‘green revolution’ in agriculture, and help ensure global food security for coming generations.
Parsons, J. (2017) Can we fix it? The Biologist 64 (4), 12-16
An accessible review on the current state of synthetic biology approaches in engineering man-made nitrogen fixing symbioses in cereal crops