title: Complete Genome Sequence of Pseudomonas chlororaphis subsp. aurantiaca Reveals a Triplicate Quorum-Sensing Mechanism for Regulation of Phenazine Production.
abstract: Pseudomonas chlororaphis subsp. aurantiaca StFRB508 regulates phenazine production through N-acyl-l-homoserine lactone (AHL)-mediated quorum sensing. Two sets of AHL-synthase and AHL-receptor genes, phzI/phzR and aurI/aurR, have been identified from the incomplete draft genome of StFRB508. In the present study, the complete genome of StFRB508, comprising a single chromosome of 6,997,933 bp, was sequenced. The complete genome sequence revealed the presence of a third quorum-sensing gene set, designated as csaI/csaR. An LC-MS/MS analysis revealed that StFRB508 produced six types of AHLs, with the most important AHL being N-(3-hydroxyhexanoyl)-l-homoserine lactone (3-OH-C6-HSL). PhzI mainly catalyzed the biosynthesis of 3-OH-C6-HSL, while AurI and CsaI catalyzed that of N-hexanoyl-l-homoserine lactone and N-(3-oxohexanoyl)-l-homoserine lactone, respectively. A mutation in phzI decreased phenazine production, whereas that in aurI or csaI did not. A phzI aurI csaI triple mutant (508ΔPACI) did not produce phenazine. Phenazine production by 508ΔPACI was stimulated by exogenous AHLs and 3-OH-C6-HSL exerted the strongest effects on phenazine production at the lowest concentration tested (0.1 μM). The plant protection efficacy of 508ΔPACI against an oomycete pathogen was lower than that of wild-type StFRB508. These results demonstrate that the triplicate quorum-sensing system plays an important role in phenazine production by and the biocontrol activity of StFRB508.
authors.affiliation: Department of Material and Environmental Chemistry, Graduate School of Engineering, Utsunomiya University.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Morohoshi
authors.forename: Takahito
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Xiaonan
authors.initials: X
authors.lastname: Xie
authors.forename: Wen-Zhao
authors.initials: WZ
authors.lastname: Wang
authors.forename: Kasumi
authors.initials: K
authors.lastname: Takeuchi
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Someya
mesh_terms: D054742:Acyl-Butyrolactones / Q000032:analysis; D002853:Chromatography, Liquid; D004252:DNA Mutational Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics*; D016680:Genome, Bacterial; D010619:Phenazines / Q000378:metabolism*; D000070096:Pseudomonas chlororaphis / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D053038:Quorum Sensing; D017422:Sequence Analysis, DNA; D015398:Signal Transduction / Q000235:genetics*; D053719:Tandem Mass Spectrometry
chemical_list: D054742:Acyl-Butyrolactones; D004269:DNA, Bacterial; D010619:Phenazines; C000598831:phenazine