Résumé
Among the major scientific questions that remain to be solved in plant pathology is how plant-pathogen interactions hold up in an ecological context? Indeed, for most interactions, we have very little idea of how interactions between plants and microbes are affected by the ecological environment in which they live. At the same time, the concept of eco-immunity has been described. Broadly speaking, this concept aims to understand and explain variation in immune response, in other words, to determine why and how biotic and abiotic factors contribute to variation in the immunity of a living organism. An ecological context that seems interesting to study for its positive impact on the control of epidemics is varietal mixtures. However, this general benefit is not systematic and can be suppressed by specific allele combinations. This highlights the need to know the genetic basis of neighbor-regulated immunity in order to make better use of mixtures. According to our first results, the plant immunity regulated by the neighborhood relies on inter-root communication events. One of our hypotheses is that this inter-root communication would be ensured by specialized metabolites exuded into the rhizosphere that has been described in the context of allelopathic mechanisms. Other phenomena that could be involved include nutrient competition in the root compartment, but the molecular mechanisms by which immunity is regulated under mixed conditions have yet to be described.