Phenotypic and physiological alterations by heterologous acylhomoserine lactone synthase expression in Pseudomonas putida.
Many bacteria harbour an incomplete quorum-sensing (QS) system, whereby they possess LuxR homologues without the QS acylhomoserine lactone (AHL) synthase, which is encoded by a luxI homologue. An artificial AHL-producing plasmid was constructed using a cviI gene encoding the C6-AHL [N-hexanoyl homoserine lactone (HHL)] synthase from Chromobacterium violaceum, and was introduced successfully into both the wild-type and a ppoR (luxR homologue) mutant of Pseudomonas putida. Our data provide evidence to suggest that the PpoR-HHL complex, but neither PpoR nor HHL alone, could attenuate growth, antibiotic resistance and biofilm formation ability. In contrast, swimming motility, siderophore production and indole degradation were enhanced by PpoR-HHL. The addition of exogenous indole increased biofilm formation and reduced swimming motility. Interestingly, indole proved ineffective in the presence of PpoR-HHL, thereby suggesting that the PpoR-HHL complex masks the effects of indole. Our data were supported by transcriptome analyses, which showed that the presence of the plasmid-encoded AHL synthase altered the expression of many genes on the chromosome in strain KT2440. Our results showed that heterologous luxI expression that occurs via horizontal gene transfer can regulate a broad range of specific target genes, resulting in alterations of the phenotype and physiology of host cells.
Lee
Yunho
Y
Division of Environmental Science and Ecological Engineering, Korea University, Seoul, Republic of Korea.
Yeom
Jinki
J
Division of Environmental Science and Ecological Engineering, Korea University, Seoul, Republic of Korea.
Kim
Jisun
J
Division of Environmental Science and Ecological Engineering, Korea University, Seoul, Republic of Korea.
Jung
Jaejoon
J
Division of Environmental Science and Ecological Engineering, Korea University, Seoul, Republic of Korea.
Jeon
Che Ok
CO
Department of Life Science, Chung-Ang University, Seoul, Republic of Korea.
Park
Woojun
W
Division of Environmental Science and Ecological Engineering, Korea University, Seoul, Republic of Korea.
D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018441:Biofilms; D002861:Chromobacterium / Q000201:enzymology*; D015870:Gene Expression; D015964:Gene Expression Regulation, Bacterial; D008025:Ligases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010641:Phenotype; D016958:Pseudomonas putida / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; C064778:LuxR autoinducer binding proteins; C088386:homoserine lactone; D008025:Ligases; D015107:4-Butyrolactone