Supervised by:

Jérôme Comte (Regular Member (Co-researcher))

Research project description

PermAdapt: Driving the ADAPTation of microbial communities of the thawing PERMafrost – Mobile genetic elements at play

Introduction

With global warming, northern ecosystems are undergoing unprecedented changes. Within permafrost, soil erosion is contributing to the formation of melting ponds. The transition from permafrost to water affects native microbial communities, forcing them to adapt to the new environment. Mobile genetic elements (MGEs) contribute to genome novelties and accelerate bacterial adaptation. Although some viruses and plasmids have been identified in these communities, their adaptive potential is not well known.

Objectives

We will identify the MGEs involved in adaptation to this aquatic environment and the function that they carry. Also, the permeability of these communities to an exogenous plasmid and the effect of an adaptive gene on plasmid propagation will be tested.

Study Sites

PermAdapt addresses HGT as one of the possible adaptive processes at play into the field of transitional Arctic ecosystems, characterizing adaptation pathways of microbial communities along a terrestrial to aquatic continuum at 2 stages of degradation of permafrost degradation: a continuous northern permafrost (Bylot Island, Nunavut) and sporadic southern permafrost (Whapmagoostui-Kuujjuarapik, Nunavik) in different environments (permafrost, active layer, sediment and water of the thermokarst)

Material and methods

The project is divided into two scientific work packages (WPs) to reach two objectives: (WP1) - Identify, quantify and assess the expression of MGEs and associated adaptive genes using “omics”, an integrative approach that combines metagenomics, metatranscriptomics and metaproteomics to identify genes involved in the adaptation of microbial communities to this new environment to deal with new osmotic, temperature, oxygen, light conditions, new carbon sources or motility in the permafrost, active layer, pond sediments and water. (WP2) –Assess effective mobility of a conjugative plasmid into transitional permafrost microbial communities with conjugative assays. Thawing-pond associated microbial communities underwent massive structure modifications from the frozen terrestrial to aquatic environments which may have deeply impacted their permissive fraction to an incoming plasmid.

Expected results

PermAdapt will assess the contribution of MGEs, especially plasmids, to the adaptive process of microbial communities on a latitudinal gradient of permafrost degradation . We expect a shift in the adaptive functions of accessory genes carried by those MGEs and an increased mobility of plasmids in thawing- permafrost microbial communities.

Research Site Coordinates