title: Interspecific cooperation: enhanced growth, attachment and strain-specific distribution in biofilms through Azospirillum brasilense-Pseudomonas protegens co-cultivation.
abstract: Plant-growth-promoting bacteria belonging to Azospirillum and Pseudomonas genera are major inhabitants of the rhizosphere. Both are increasingly commercialized as crops inoculants. Interspecific interaction in the rhizosphere is critical for inoculants aptness. The objective of this work was to evaluate Azospirillum and Pseudomonas interaction in mixed biofilms by co-cultivation of the model strains Azospirillum brasilense Sp245 and Pseudomonas protegens CHA0. The results revealed enhanced growth of both strains when co-cultured in static conditions. Moreover, Sp245 biofilm formed in plastic surfaces was increased 2-fold in the presence of CHA0. Confocal microscopy revealed highly structured mixed biofilms showing Sp245 mainly on the bottom and CHA0 towards the biofilm surface. In addition, A. brasilense biofilm was thicker and denser when co-cultured with P. protegens. In a colony-colony interaction assay, Sp245 changed nearby CHA0 producing small colony phenotype, which accounts for a diffusible metabolite mediator; though CHA0 spent medium did not affect Sp245 colony phenotype. Altogether, these results point to a cooperative interaction between A. brasilense Sp245 and P. protegens CHA0 in which both strains increase their static growth and produce structured mixed biofilms with a strain-specific distribution.
authors.affiliation: Laboratorio de Bioquímica Vegetal y Microbiana, CONICET, FCA, Universidad Nacional de Mar del Plata (UNMdP), CC 276 (7620) Balcarce, Argentina.
authors.forename: Luciana A
authors.initials: LA
authors.lastname: Pagnussat
authors.affiliation: Laboratorio de Bioquímica Vegetal y Microbiana, CONICET, FCA, Universidad Nacional de Mar del Plata (UNMdP), CC 276 (7620) Balcarce, Argentina.
authors.forename: Florencia
authors.initials: F
authors.lastname: Salcedo
authors.affiliation: Laboratorio de Bioquímica Vegetal y Microbiana, CONICET, FCA, Universidad Nacional de Mar del Plata (UNMdP), CC 276 (7620) Balcarce, Argentina.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Maroniche
authors.affiliation: Departement de Microbiologie Fondamentale (DMF), Universite de Lausanne, Batiment Biophore, Quartier UNIL-Sorge, CH-1015 Lausanne, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: Keel
authors.affiliation: Laboratorio de Bioquímica, Microbiología e Interacciones Biológicas en el Suelo, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes (UNQ), CONICET, Bernal 1876, Argentina.
authors.forename: Claudio
authors.initials: C
authors.lastname: Valverde
authors.affiliation: Laboratorio de Bioquímica Vegetal y Microbiana, FCA, Universidad Nacional de Mar del Plata (UNMdP), CC 276 (7620) Balcarce, Argentina creuspi@hotmail.com.
authors.forename: Cecilia M
authors.initials: CM
authors.lastname: Creus
mesh_terms: D015806:Azospirillum brasilense / Q000254:growth & development* / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development*; D018920:Coculture Techniques; D018517:Plant Roots / Q000382:microbiology; D010944:Plants / Q000382:microbiology*; D011549:Pseudomonas / Q000254:growth & development* / Q000378:metabolism; D058441:Rhizosphere; D012988:Soil Microbiology
keywords: biofilm structure; colony phenotype; plant-growth-promoting-bacteria