Free-living, psychrotrophic bacteria of the Genus Psychrobacter are descendants of pathobionts

Welter Daphne K., Ruaud Albane, Henseler Zachariah M., De Jong Hannah N., Van Coeverden de Groot Peter, Michaux Johan, Gormezano Linda, Waters Jillian L., Youngblut Nicholas D., Ley Ruth E.. 2021. Free-living, psychrotrophic bacteria of the Genus Psychrobacter are descendants of pathobionts. mSystems, 6 (2), 20 p.

Url - jeu de données - Entrepôt autre : https://www.ebi.ac.uk/ena/browser/view/PRJEB40380 / Url - autres données associées : https://github.com/dkwelter/Welter_et_al_2020

Quartile : Q1, Sujet : MICROBIOLOGY

Résumé : Host-adapted microorganisms are generally assumed to have evolved from free-living, environmental microorganisms, as examples of the reverse process are rare. In the phylum Gammaproteobacteria, family Moraxellaceae, the genus Psychrobacter includes strains from a broad ecological distribution including animal bodies as well as sea ice and other nonhost environments. To elucidate the relationship between these ecological niches and Psychrobacter's evolutionary history, we performed tandem genomic analyses with phenotyping of 85 Psychrobacter accessions. Phylogenomic analysis of the family Moraxellaceae reveals that basal members of the Psychrobacter clade are Moraxella spp., a group of often-pathogenic organisms. Psychrobacter exhibited two broad growth patterns in our phenotypic screen: one group that we called the “flexible ecotype” (FE) had the ability to grow between 4 and 37°C, and the other, which we called the “restricted ecotype” (RE), could grow between 4 and 25°C. The FE group includes phylogenetically basal strains, and FE strains exhibit increased transposon copy numbers, smaller genomes, and a higher likelihood to be bile salt resistant. The RE group contains only phylogenetically derived strains and has increased proportions of lipid metabolism and biofilm formation genes, functions that are adaptive to cold stress. In a 16S rRNA gene survey of polar bear fecal samples, we detect both FE and RE strains, but in in vivo colonizations of gnotobiotic mice, only FE strains persist. Our results indicate the ability to grow at 37°C, seemingly necessary for mammalian gut colonization, is an ancestral trait for Psychrobacter, which likely evolved from a pathobiont. IMPORTANCE Host-associated microbes are generally assumed to have evolved from free-living ones. The evolutionary transition of microbes in the opposite direction, from host associated toward free living, has been predicted based on phylogenetic data but not studied in depth. Here, we provide evidence that the genus Psychrobacter, particularly well known for inhabiting low-temperature, high-salt environments such as sea ice, permafrost soils, and frozen foodstuffs, has evolved from a mammalian-associated ancestor. We show that some Psychrobacter strains retain seemingly ancestral genomic and phenotypic traits that correspond with host association while others have diverged to psychrotrophic or psychrophilic lifestyles.

Mots-clés Agrovoc : phylogénie, génome, écotype, phénotype, tolérance au sel, Moraxella, micro-organisme psychrophile, croissance, séquence nucléotidique, écologie animale, aptitude à coloniser, génie génétique, sel biliaire, glace d'eau de mer

Mots-clés géographiques Agrovoc : France

Mots-clés libres : Genomics, Phylogeny, Psychrobacter, Psychrophiles

Agences de financement hors UE : Max Planck Society, Nunavut General Monitoring Plan, National Science and Engineering Research Council, Environment Canada

Auteurs et affiliations

• Welter Daphne K., Max Planck Institute for Developmental Biology (DEU)
• Ruaud Albane, Max Planck Institute for Developmental Biology (DEU)
• Henseler Zachariah M., Max Planck Institute for Developmental Biology (DEU)
• De Jong Hannah N., Max Planck Institute for Developmental Biology (DEU)
• Van Coeverden de Groot Peter, Queen's University (CAN)
• Michaux Johan, CIRAD-BIOS-UMR ASTRE (FRA)
• Gormezano Linda, AMNH (USA)
• Waters Jillian L., Max Planck Institute for Developmental Biology (DEU)
• Youngblut Nicholas D., Max Planck Institute for Developmental Biology (DEU)
• Ley Ruth E., Max Planck Institute for Developmental Biology (DEU) - auteur correspondant

Source : Cirad-Agritrop (https://agritrop.cirad.fr/607097/)

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