Biotic regulation of symbioses signalling

Nitrogen (N) is a major macronutrient for plant productivity. As a paradox, N is poorly available in soils, leading to extensive and costly fertiliser applications to sustain crop yields. Since the early 20th century, the use of N fertilizers has gradually increased to fulfil the demand of a growing population. Paradoxically, it has been estimated that 50-70% of the nitrogen provided to the soil is lost, giving rise to soil and water pollution as well as global warming through emissions of nitrous oxide. Lowering fertilizer input and breeding crops with better nitrogen use efficiency is one of the main goals of plant nutrition research. Root legume symbioses are natural fertilizer for the plants via the association with nitrogen fixing-bacteria and phosphate delivering arbuscular mycorrhiza. However, in the rhizosphere, plant roots are exposed to an array of microorganisms including pathogens. Beneficial symbiotic organisms must evade plant defences in order to colonize host roots.
This project will define a novel molecular mechanism at the interplay between symbioses and defence using a combination of in vivo imaging analyses, genetics, molecular biology and proteomics.