Résumé
Roots of wheat and other cereals interact with a huge range of soil microorganisms, which colonize the rhizosphere and/or root tissues. This root-associated microbial community (sometimes termed the root microbiome) is important to consider because it includes both deleterious and symbiotic microorganisms. Therefore, it has a significant impact on plant growth, health and tolerance to stress. In this context, understanding root microbiome assembly and dynamics is of fundamental interest and could help design microbiome-based strategies for crop management. To address this issue, the significance of cereal genotype for root-microbiome interactions was studied. A relationship was found when comparing rhizobacterial communities with the phylogenetic distance between the corresponding plant genotypes, but this relationship held true only for a fraction of the community. It prompted us to assess how plant hosts selected for specific bacteria with plant-beneficial potential. This type of screening showed that the ability to interact with plant-beneficial bacteria had been largely counter-selected in modern wheat cultivars, yet it had been retained in some of them. The implications for plant-microbe interactions and breeding will be discussed.