Format: ORAL

Victor Angot1, Yanis Bouchenak-Khelladi1

1 UMR Agroécologie, Université de Bourgogne INRAE, Dijon, France

The discovery of the holobiont in plants (host plant-microorganism association), particularly in angiosperms have revolutionized our understanding of the effects on the physiology and ecology of associated plants. The plant-microorganism interaction is governed by a chemical dialogue via the production of exudates by the plant which selects and recruits bacterial communities which, in return, produce metabolites which facilitate the acquisition of nutrients and help promote the growth of the host plant. Symbiotic relationships between plants and microorganisms are the most documented, such as Rhizobia strains associated with root nodulating legumes that facilitate N uptake. Beyond these associations, non-symbiotic bacteria also impact their host. Significant gaps persist in understanding these complex microbial associations and require holistic approaches at different temporal and spatial scales. In this study, we conducted a greenhouse experiment to characterize the microbial communities associated with Pisum throughout its developmental cycle and in four compartments or microhabitats provided by the host plant. Microbiomes from four compartments of 144 plants from four different Pisum genotypes (Pisum fulvum, P. sativum subsp. abyssinicum, P. sativum subsp. elatius and P. sativum subsp. sativum) were sampled at three distinct developmental stages, representing a total of 456 microbial communities. These microbiomes were analyzed using full 16S rRNA gene PACBIO sequencing and phylogenetically-corrected statistical analyses. Our results suggest that the plant-associated microbiome composition and structure evolved throughout the plants developmental cycle, likely in response to differential nitrogen and carbon allocations during vegetative, flowering, and seed-filling stages. The different microhabitats offered by the plant acted as ecological filters, influencing the composition of bacterial communities. Finally, bacterial communities associated with peas exhibited differences based on the genotype of the host plant. These findings enhance our understanding of the dynamics of bacterial communities and the hosts influence in shaping this process.