title: Pseudomonas putida F1 has multiple chemoreceptors with overlapping specificity for organic acids.
abstract: Previous studies have demonstrated that Pseudomonas putida strains are not only capable of growth on a wide range of organic substrates, but also chemotactic towards many of these compounds. However, in most cases the specific chemoreceptors that are involved have not been identified. The complete genome sequences of P. putida strains F1 and KT2440 revealed that each strain is predicted to encode 27 methyl-accepting chemotaxis proteins (MCPs) or MCP-like proteins, 25 of which are shared by both strains. It was expected that orthologous MCPs in closely related strains of the same species would be functionally equivalent. However, deletion of the gene encoding the P. putida F1 orthologue (locus tag Pput_4520, designated mcfS) of McpS, a known receptor for organic acids in P. putida KT2440, did not result in an obvious chemotaxis phenotype. Therefore, we constructed individual markerless MCP gene deletion mutants in P. putida F1 and screened for defective sensory responses to succinate, malate, fumarate and citrate. This screen resulted in the identification of a receptor, McfQ (locus tag Pput_4894), which responds to citrate and fumarate. An additional receptor, McfR (locus tag Pput_0339), which detects succinate, malate and fumarate, was found by individually expressing each of the 18 genes encoding canonical MCPs from strain F1 in a KT2440 mcpS-deletion mutant. Expression of mcfS in the same mcpS deletion mutant demonstrated that, like McfR, McfS responds to succinate, malate, citrate and fumarate. Therefore, at least three receptors, McfR, McfS, and McfQ, work in concert to detect organic acids in P. putida F1.
authors.affiliation: Department of Microbiology, College of Biological Sciences, University of California, Davis, CA, USA.
authors.forename: Rebecca E
authors.initials: RE
authors.lastname: Parales
authors.affiliation: Department of Microbiology, College of Biological Sciences, University of California, Davis, CA, USA.
authors.forename: Rita A
authors.initials: RA
authors.lastname: Luu
authors.affiliation: Department of Microbiology, College of Biological Sciences, University of California, Davis, CA, USA.
authors.forename: Grischa Y
authors.initials: GY
authors.lastname: Chen
authors.affiliation: Department of Microbiology, College of Biological Sciences, University of California, Davis, CA, USA.
authors.forename: Xianxian
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Microbiology, College of Biological Sciences, University of California, Davis, CA, USA.
authors.forename: Victoria
authors.initials: V
authors.lastname: Wu
authors.affiliation: Department of Microbiology, College of Biological Sciences, University of California, Davis, CA, USA.
authors.forename: Pamela
authors.initials: P
authors.lastname: Lin
authors.affiliation: Department of Microbiology, College of Biological Sciences, University of California, Davis, CA, USA.
authors.forename: Jonathan G
authors.initials: JG
authors.lastname: Hughes
authors.affiliation: Department of Microbiology, College of Biological Sciences, University of California, Davis, CA, USA.
authors.forename: Vasyl
authors.initials: V
authors.lastname: Nesteryuk
authors.affiliation: Department of Microbiology, College of Biological Sciences, University of California, Davis, CA, USA.
authors.forename: Juanito V
authors.initials: JV
authors.lastname: Parales
authors.affiliation: Department of Biology, University of St. Thomas, St. Paul, MN, USA.
authors.forename: Jayna L
authors.initials: JL
authors.lastname: Ditty
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002264:Carboxylic Acids / Q000378:metabolism*; D002633:Chemotaxis; D017353:Gene Deletion; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D000072236:Methyl-Accepting Chemotaxis Proteins; D016958:Pseudomonas putida / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D002264:Carboxylic Acids; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins