title: Assessment of the contribution of chemoreceptor-based signalling to biofilm formation.
abstract: Although it is well established that one- and two-component regulatory systems participate in regulating biofilm formation, there also exists evidence suggesting that chemosensory pathways are also involved. However, little information exists about which chemoreceptors and signals modulate this process. Here we report the generation of the complete set of chemoreceptor mutants of Pseudomonas putida KT2440 and the identification of four mutants with significantly altered biofilm phenotypes. These receptors are a WspA homologue of Pseudomonas aeruginosa, previously identified to control biofilm formation by regulating c-di-GMP levels, and three uncharacterized chemoreceptors. One of these receptors, named McpU, was found to mediate chemotaxis towards different polyamines. The functional annotation of McpU was initiated by high-throughput thermal shift assays of the receptor ligand binding domain (LBD). Isothermal titration calorimetry showed that McpU-LBD specifically binds putrescine, cadaverine and spermidine, indicating that McpU represents a novel chemoreceptor type. Another uncharacterized receptor, named McpA, specifically binds 12 different proteinogenic amino acids and mediates chemotaxis towards these compounds. We also show that mutants in McpU and WspA-Pp have a significantly reduced ability to colonize plant roots. Data agree with other reports showing that polyamines are signal molecules involved in the regulation of bacteria-plant communication and biofilm formation.
authors.affiliation: Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/Prof. Albareda 1, 18008, Granada, Spain.
authors.forename: Andrés
authors.initials: A
authors.lastname: Corral-Lugo
authors.affiliation: Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/Prof. Albareda 1, 18008, Granada, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: De la Torre
authors.affiliation: Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/Prof. Albareda 1, 18008, Granada, Spain.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Matilla
authors.affiliation: Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/Prof. Albareda 1, 18008, Granada, Spain.
authors.forename: Matilde
authors.initials: M
authors.lastname: Fernández
authors.affiliation: Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/Prof. Albareda 1, 18008, Granada, Spain.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Morel
authors.affiliation: Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/Prof. Albareda 1, 18008, Granada, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Espinosa-Urgel
authors.affiliation: Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/Prof. Albareda 1, 18008, Granada, Spain. tino.krell@eez.csic.es.
authors.forename: Tino
authors.initials: T
authors.lastname: Krell
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018441:Biofilms; D002633:Chemotaxis; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000502:physiology*; D016958:Pseudomonas putida / Q000235:genetics / Q000502:physiology*
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins