Integrons in Arctic Air: Exploring the drivers behind integron diversity in the Arctic atmosphere and integron integrase gene expression under simulated atmospheric conditions.

In the current context of the “One-Health” concept, the importance of assessing and monitoring microbial biodiversity and ecology in all environmental compartments is becoming increasingly apparent. However, although the atmosphere participates in worldwide dispersal of microorganisms and their genetic material, it has been relatively little studied compared to freshwater, marine and soil ecosystems. Recently, concerns have been raised about the atmospheric dispersal of antibiotic-resistant genes (ARGs). Interestingly, ARGs are part of integrons, important bacterial genomic elements that facilitate the dispersal and acquisition of genetic material. In this context, the main objective of the two-year IntegrAAir project is to assess the ecodynamic of integrons in the atmosphere and assess their impacts on human and ecosystems health. It relies on the hypothesis that aerosolization can impact integron dynamic by inducing the integron integrase gene expression and thus mobilizing new genetic elements from the environmental gene pool. In order to respond to this hypothesis, two main sub-objectives are planned: (i) Understand the drivers behind integron complexity in the Arctic boundary layer using an omics approach, the Arctic being an ideal environment to attempt to focus primarily on environmental integrons, as it is little impacted by anthropogenic sources; (ii) Understand whether aerosolization can affect integron dynamics (gene gain and loss). We will investigate the integron integrase gene expression under simulated atmospheric conditions, using unique atmospheric chambers developed by the host research team. Overall, the project will provide new insights in the fields of aeromicrobiology and microbial ecology, as well as for public health, with regard to the impact of atmospheric transport on bacterial evolution and adaptation, and integron ecology in an environmental context.