title: Identification of Pseudomonas fluorescens chemotaxis sensory proteins for malate, succinate, and fumarate, and their involvement in root colonization.
abstract: Pseudomonas fluorescens Pf0-1 exhibited chemotactic responses to l-malate, succinate, and fumarate. We constructed a plasmid library of 37 methyl-accepting chemotaxis protein (MCP) genes of P. fluorescens Pf0-1. To identify a MCP for l-malate, the plasmid library was screened using the PA2652 mutant of Pseudomonas aeruginosa PAO1, a mutant defective in chemotaxis to l-malate. The introduction of Pfl01_0728 and Pfl01_3768 genes restored the ability of the PA2652 mutant to respond to l-malate. The Pfl01_0728 and Pfl01_3768 double mutant of P. fluorescens Pf0-1 showed no response to l-malate or succinate, while the Pfl01_0728 single mutant did not respond to fumarate. These results indicated that Pfl01_0728 and Pfl01_3768 were the major MCPs for l-malate and succinate, and Pfl01_0728 was also a major MCP for fumarate. The Pfl01_0728 and Pfl01_3768 double mutant unexpectedly exhibited stronger responses toward the tomato root exudate and amino acids such as proline, asparagine, methionine, and phenylalanine than those of the wild-type strain. The ctaA, ctaB, ctaC (genes of the major MCPs for amino acids), Pfl01_0728, and Pfl01_3768 quintuple mutant of P. fluorescens Pf0-1 was less competitive than the ctaA ctaB ctaC triple mutant in competitive root colonization, suggesting that chemotaxis to l-malate, succinate, and/or fumarate was involved in tomato root colonization by P. fluorescens Pf0-1.
authors.affiliation: Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University.
authors.forename: Shota
authors.initials: S
authors.lastname: Oku
authors.forename: Ayaka
authors.initials: A
authors.lastname: Komatsu
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Nakashimada
authors.forename: Takahisa
authors.initials: T
authors.lastname: Tajima
authors.forename: Junichi
authors.initials: J
authors.lastname: Kato
mesh_terms: D002633:Chemotaxis; D005650:Fumarates / Q000378:metabolism*; D015723:Gene Library; D005816:Genetic Complementation Test; D018551:Solanum lycopersicum / Q000382:microbiology*; D008293:Malates / Q000378:metabolism*; D009154:Mutation; D018517:Plant Roots / Q000382:microbiology*; D010957:Plasmids; D011506:Proteins; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000502:physiology; D011551:Pseudomonas fluorescens / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D019802:Succinic Acid / Q000378:metabolism*
chemical_list: D005650:Fumarates; D008293:Malates; D011506:Proteins; C030298:malic acid; D019802:Succinic Acid