Format: ORAL

Yanis BOUCHENAK-KHELLADI1

1 UMR Agroécologie, Université de Bourgogne, Dijon, France

As early as the 19th century, Darwin and Wallace considered the importance of plant-biotic interactions in promoting diversity and the intensity of selection. The extent to which coevolution may drive natural selection and shape angiosperm diversity is still debated, particularly because no unequivocal evidence has been provided regarding reciprocal evolutionary changes. For instance, the use of phylogenetic trees for the study of coevolutionary processes turns out to be inconclusive because phylogenetic patterns of coevolution exclusively reflect codivergence phenomena. The concept of coevolution is still subject to multiple debates and, apart from semantic questions, reflects the need to develop experimental approaches which take into account the complexity of biotic interactions. Experimental approaches under controlled conditions have been able to highlight selection pressures exerted by organisms connected in food networks generating changes in allelic frequencies. However, when species are integrated into complex and diverse interaction networks under natural conditions, reciprocal selection pressures can vary in time and space and depend on the ecosystem under study. Despite the known benefits of plant microbiota on growth and nutrition, the mechanisms of association and their degree of heritability remain largely unknown whereas they do constitute the basis and requirements for coevolution to occur. Here, I will highlight the suitability of studying plant-microorganisms interactions to disentangle the mechanisms and dynamics of biotic associations in light of coevolutionary processes. Studying genetic variability, gene expressions and functional responses of plant-microorganisms associations would provide exceptional insights on the mechanistic processes of coevolution.