Abstract :
[en] Before the domestication of plants, plant pathogens, including plant viruses, were co-evolving with wild plants growing in mixed species communities, thereby resulting in complex interactions. Plant viruses can be detrimental, but also commensal or even mutualistic for their hosts. Moreover, mixed-infections are very frequent in wild plants, which still increases the complexity of these relations (through antagonistic, mutualistic or coexistence interactions between viruses). The development of agriculture deeply modified the ecosystems, drastically reducing their biodiversity, raising their instability and disrupting the host-pathogen co-evolution. This instability impacts plants, vectors and viruses alike and alters the dynamics of virus-plant pathosystems which, in turn, drives the accelerated rate of virus evolution and emergence in response to changing circumstances. Moreover, the whole process is being exacerbated now by the climate change and the continuous world trade growth. Virus emergence, that is the introduction of new viruses in specific area, the emergence of new strains or the emergence of endemic viruses in newly introduced crops or cultivars, represents 47% of plant pathogen emergence worldwide. The global objective of this project is to study the impact of ecosystems with contrasted biodiversity on the virome of Poaceae plant species. These ecosystems are already localized in the National Park “Burdinale-Mehaigne” and include: monoculture crop, intensive pasture and pasture with high biological value. These ecosystems encompass cultivated, lawn, pasture, weed and pasture grasses at the interface between indigenous vegetation and cultivated areas. Virome comparison and standard population genetic analyses will provide information on the role of habitat biodiversity in shaping virome diversity, infection patterns and virus adaptation to host. The results will also inform on the role of wild or bordering ecosystems as reservoirs for infection of crops and pasture, and vice versa. This research has the potential to provide critical information not only on viral threats to biodiversity and cultivated species in contrasting environments, but also on virus evolution in diverse ecosystems.
