title: Experimental Evaluation of Host Adaptation of Lactobacillus reuteri to Different Vertebrate Species.
abstract: The speciesLactobacillus reuterihas diversified into host-specific lineages, implying a long-term association with different vertebrates. Strains from rodent lineages show specific adaptations to mice, but the processes underlying the evolution ofL. reuteriin other hosts remain unknown. We administered three standardized inocula composed of strains from different host-confined lineages to mice, pigs, chickens, and humans. The ecological performance of each strain in the gastrointestinal tract of each host was determined by typing random colonies recovered from fecal samples collected over five consecutive days postadministration. Results revealed that rodent strains were predominant in mice, confirming previous findings of host adaptation. In chickens, poultry strains of the lineage VI (poultry VI) and human isolates from the same lineage (human VI) were recovered at the highest and second highest rates, respectively. Interestingly, human VI strains were virtually undetected in human feces. These findings, together with ancestral state reconstructions, indicate poultry VI and human VI strains share an evolutionary history with chickens. Genomic analysis revealed that poultry VI strains possess a large and variable accessory genome, whereas human VI strains display low genetic diversity and possess genes encoding antibiotic resistance and capsular polysaccharide synthesis, which might have allowed temporal colonization of humans. Experiments in pigs and humans did not provide evidence of host adaptation ofL. reuterito these hosts. Overall, our findings demonstrate host adaptation ofL. reuterito rodents and chickens, supporting a joint evolution of this bacterial species with several vertebrate hosts, although questions remain about its natural history in humans and pigs.IMPORTANCEGut microbes are often hypothesized to have coevolved with their vertebrate hosts. However, the evidence is sparse and the evolutionary mechanisms have not been identified. We developed and applied an experimental approach to determine host adaptation ofL. reuterito different hosts. Our findings confirmed adaptation to rodents and provided evidence of adaptation to poultry, suggesting thatL. reuterievolved via natural selection in different hosts. By complementing phylogenetic analyses with experimental evidence, this study provides novel information about the mechanisms driving host-microbe coevolution with vertebrates and serve as a basis to inform the application ofL. reuterias a probiotic for different host species.
authors.affiliation: Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.|Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska, USA.|CEGIIR, University of Alberta, Edmonton, AB, Canada.
authors.forename: Rebbeca M
authors.identifier: http://orcid.org/0000-0002-2723-2237
authors.initials: RM
authors.lastname: Duar
authors.affiliation: Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska, USA.|Evolve Biosystems, Inc., Davis, California, USA.
authors.forename: Steven A
authors.initials: SA
authors.lastname: Frese
authors.affiliation: Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.|CEGIIR, University of Alberta, Edmonton, AB, Canada.
authors.forename: Xiaoxi B
authors.initials: XB
authors.lastname: Lin
authors.affiliation: Department of Animal Science, University of Nebraska, Lincoln, Nebraska, USA.
authors.forename: Samodha C
authors.initials: SC
authors.lastname: Fernando
authors.affiliation: Department of Animal Science, University of Nebraska, Lincoln, Nebraska, USA.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Burkey
authors.affiliation: CEGIIR, University of Alberta, Edmonton, AB, Canada.
authors.forename: Guergana
authors.initials: G
authors.lastname: Tasseva
authors.affiliation: Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska, USA.|Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Peterson
authors.affiliation: Bioinformatics and Systems Biology, Justus Liebig University, Giessen, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Blom
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
authors.forename: Cory Q
authors.initials: CQ
authors.lastname: Wenzel
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.|Department of Microbiology and Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Szymanski
authors.affiliation: Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada jwalter1@ualberta.ca.|Department of Food Science and Technology, University of Nebraska, Lincoln, Nebraska, USA.|Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.|CEGIIR, University of Alberta, Edmonton, AB, Canada.
authors.forename: Jens
authors.initials: J
authors.lastname: Walter
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D005075:Biological Evolution; D002645:Chickens / Q000382:microbiology; D041981:Gastrointestinal Tract / Q000382:microbiology; D058507:Host Specificity; D006801:Humans / Q000382:microbiology; D052200:Limosilactobacillus reuteri / Q000145:classification / Q000235:genetics / Q000502:physiology*; D051379:Mice / Q000382:microbiology; D010802:Phylogeny; D013552:Swine / Q000382:microbiology; D014714:Vertebrates / Q000382:microbiology*
keywords: Lactobacillus reuteri; host adaptation; probiotics; symbiosis