Adaptation in Toxic Environments: Arsenic Genomic Islands in the Bacterial Genus Thiomonas

Kelle Freel (1) , Martin Krueger (2) , Julien Farasin (1) , Céline Brochier-Armanet (3) , Valérie Barbe (4) , Jérémy Andres (1) , Pierre-Etienne Cholley (1) , Marie-Agnès Dillies (5) , Bernd Jagla (5) , Sandrine Koechler (1) , Yann Leva (6) , Ghislaine Magdelenat (4) , Frederic Plewniak (1) , Caroline Proux (5) , Jean-Yves Coppée (5) , Philippe Bertin (1) , Hermann Heipieper (2) , Florence Arsène-Ploetze (1) , Hemant Purohit (7)

1 GMGM - Génétique moléculaire, génomique, microbiologie
2 UFZ - Helmholtz Zentrum für Umweltforschung = Helmholtz Centre for Environmental Research
3 BPGE - Bioinformatique, phylogénie et génomique évolutive
4 GENOSCOPE - Genoscope - Centre national de séquençage [Evry]
5 PF2 - Transcriptome et Epigénome
6 Université de Haute-Alsace (UHA) - Université de Haute-Alsace (UHA) Mulhouse - Colmar
7 Wright State University

Acid mine drainage (AMD) is a highly toxic environment for most living organisms due to the presence of many lethal elements including arsenic (As). Thiomonas (Tm.) bacteria are found ubiquitously in AMD and can withstand these extreme conditions, in part because they are able to oxidize arsenite. In order to further improve our knowledge concerning the adaptive capacities of these bacteria, we sequenced and assembled the genome of six isolates derived from the Carnoulès AMD, and compared them to the genomes of Tm. arsenitoxydans 3As (isolated from the same site) and Tm. intermedia K12 (isolated from a sewage pipe). A detailed analysis of the Tm. sp. CB2 genome revealed various rearrangements had occurred in comparison to what was observed in 3As and K12 and over 20 genomic islands (GEIs) were found in each of these three genomes. We performed a detailed comparison of the two arsenic-related islands found in CB2, carrying the genes required for arsenite oxidation and As resistance, with those found in K12, 3As, and five other Thiomonas strains also isolated from Carnoulès (CB1, CB3, CB6, ACO3 and ACO7). Our results suggest that these arsenic-related islands have evolved differentially in these closely related Thiomonas strains, leading to divergent capacities to survive in As rich environments.

Domaines: Sciences du Vivant [q-bio]

Kelle Freel, Martin Krueger, Julien Farasin, Céline Brochier-Armanet, Valérie Barbe, et al.. Adaptation in Toxic Environments: Arsenic Genomic Islands in the Bacterial Genus Thiomonas. PLoS ONE, 2015, 10 (9), pp.0139011. ⟨10.1371/journal.pone.0139011⟩. ⟨cea-01825879⟩