title: Chemotaxis and adherence to fungal surfaces are key components of the behavioral response of Burkholderia terrae BS001 to two selected soil fungi.
abstract: Burkholderia terrae BS001 has previously been proposed to be a 'generalist' associate of soil fungi, but its strategies of interaction have been largely ignored. Here, we studied the chemotactic behavior of B. terrae BS001 towards Lyophyllum sp. strain Karsten and Trichoderma asperellum 302 and the role of fungal surface molecules in their physical interaction with the bacteria. To assess the involvement of the type 3 secretion system (T3SS), wild-type strain BS001 and T3SS mutant strain BS001-ΔsctD were used in the experiments. First, the two fungi showed divergent behavior when confronted with B. terrae BS001 on soil extract agar medium. Lyophyllum sp. strain Karsten revealed slow growth towards the bacterium, whereas T. asperellum 302 grew avidly over it. Both on soil extract and M9 agar, B. terrae BS001 and BS001-ΔsctD moved chemotactically towards the hyphae of both fungi, with a stronger response to Lyophyllum sp. strain Karsten than to T. asperellum 302. The presence of a progressively increasing glycerol level in the M9 agar enhanced the level of movement. Different oxalic acid concentrations exerted varied effects, with a significantly raised chemotactic response at lower, and a subdued response at higher concentrations. Testing of the adherence of B. terrae BS001 and BS001-ΔsctD to Lyophyllum sp. strain Karsten and to cell envelope-extracted ceramide monohexosides (CMHs) revealed that CMHs in both conidia and hyphae could bind strain BS001 cells. As BS001-ΔsctD adhered significantly less to the CMHs than BS001, the T3SS was presumed to have a role in the interaction. In contrast, such avid adherence was not detected with T. asperellum 302. Thus, B. terrae BS001 shows a behavior characterized by swimming towards Lyophyllum sp. strain Karsten and T. asperellum 302 and attachment to the CMH moiety in the cell envelope, in particular of the former.
authors: Microbial Ecology, Groningen Institute of Evolutionary Life Sciences (GELIFES), Nijenborgh 7, 9747 AG, University of Groningen, The Netherlands i.u.haq@rug.nl.
authors: Irshad Ul
authors: IU
authors: Haq
authors: Microbial Ecology, Groningen Institute of Evolutionary Life Sciences (GELIFES), Nijenborgh 7, 9747 AG, University of Groningen, The Netherlands Departamento de Microbiologia Geral, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, UFRJ, 21941-902, Rio de Janeiro, Brazil.
authors: Renata Oliveira da Rocha
authors: RO
authors: Calixto
authors: Microbial Ecology, Groningen Institute of Evolutionary Life Sciences (GELIFES), Nijenborgh 7, 9747 AG, University of Groningen, The Netherlands.
authors: Pu
authors: P
authors: Yang
authors: Departamento de Microbiologia Geral, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, UFRJ, 21941-902, Rio de Janeiro, Brazil.
authors: Giulia Maria Pires
authors: GM
authors: Dos Santos
authors: Departamento de Microbiologia Geral, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, UFRJ, 21941-902, Rio de Janeiro, Brazil.
authors: Eliana
authors: E
authors: Barreto-Bergter
authors: Microbial Ecology, Groningen Institute of Evolutionary Life Sciences (GELIFES), Nijenborgh 7, 9747 AG, University of Groningen, The Netherlands.
authors: Jan Dirk
authors: JD
authors: van Elsas
mesh_terms: D000363:Agaricales / Q000378:metabolism*; D001422:Bacterial Adhesion / Q000502:physiology*; D001665:Binding Sites / Q000502:physiology; D018441:Biofilms / Q000254:growth & development*; D019117:Burkholderia / Q000378:metabolism*; D002450:Cell Communication; D002633:Chemotaxis / Q000502:physiology*; D005990:Glycerol / Q000494:pharmacology; D025301:Hyphae / Q000378:metabolism; D019815:Oxalic Acid / Q000494:pharmacology; D012987:Soil; D012988:Soil Microbiology; D013172:Spores, Fungal / Q000378:metabolism; D014242:Trichoderma / Q000378:metabolism*
chemical_list: D012987:Soil; D019815:Oxalic Acid; D005990:Glycerol
keywords: Lyophyllum sp. strain Karsten; Trichoderma asperellum 302; bacterial–fungal interaction; ceramide monohexosides; chemotaxis