title: Cooperative adaptation to establishment of a synthetic bacterial mutualism.
abstract: To understand how two organisms that have not previously been in contact can establish mutualism, it is first necessary to examine temporal changes in their phenotypes during the establishment of mutualism. Instead of tracing back the history of known, well-established, natural mutualisms, we experimentally simulated the development of mutualism using two genetically-engineered auxotrophic strains of Escherichia coli, which mimic two organisms that have never met before but later establish mutualism. In the development of this synthetic mutualism, one strain, approximately 10 hours after meeting the partner strain, started oversupplying a metabolite essential for the partner's growth, eventually leading to the successive growth of both strains. This cooperative phenotype adaptively appeared only after encountering the partner strain but before the growth of the strain itself. By transcriptome analysis, we found that the cooperative phenotype of the strain was not accompanied by the local activation of the biosynthesis and transport of the oversupplied metabolite but rather by the global activation of anabolic metabolism. This study demonstrates that an organism has the potential to adapt its phenotype after the first encounter with another organism to establish mutualism before its extinction. As diverse organisms inevitably encounter each other in nature, this potential would play an important role in the establishment of a nascent mutualism in nature.
authors.affiliation: Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Suita, Japan.
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Hosoda
authors.forename: Shingo
authors.initials: S
authors.lastname: Suzuki
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Yamauchi
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Shiroguchi
authors.forename: Akiko
authors.initials: A
authors.lastname: Kashiwagi
authors.forename: Naoaki
authors.initials: N
authors.lastname: Ono
authors.forename: Kotaro
authors.initials: K
authors.lastname: Mori
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yomo
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics / Q000502:physiology*; D001419:Bacteria / Q000235:genetics* / Q000254:growth & development; D018407:Bacterial Physiological Phenomena / Q000235:genetics; D018920:Coculture Techniques / Q000379:methods; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D007532:Isoleucine / Q000235:genetics / Q000378:metabolism; D007930:Leucine / Q000235:genetics / Q000378:metabolism; D056265:Microbial Interactions / Q000235:genetics*; D008828:Microbiological Techniques; D008954:Models, Biological; D030781:Organisms, Genetically Modified / Q000502:physiology*; D013559:Symbiosis / Q000235:genetics* / Q000502:physiology
chemical_list: D007532:Isoleucine; D007930:Leucine