The biocontrol strain Pseudomonas fluorescens F113 produces the Rhizobium small bacteriocin, N-(3-hydroxy-7-cis-tetradecenoyl)homoserine lactone, via HdtS, a putative novel N-acylhomoserine lactone synthase.
Several different species of Pseudomonas: produce N:-acylhomoserine lactones (AHLs), quorum-sensing signal molecules which are involved in the cell-density-dependent control of secondary metabolite and virulence gene expression. When Pseudomonas fluorescens F113 was cross-streaked against AHL biosensors capable of sensitively detecting either short (C(4)-C(8)) or long (C(10)-C(14)) acyl chain AHLs, no activity was detectable. However, by extracting cell-free stationary-phase culture supernatants with dichloromethane followed by reverse-phase HPLC, three distinct fractions were obtained capable of activating the AHL biosensors. Three AHLs were subsequently characterized using high-resolution MS and chemical synthesis. These were (i) N:-(3-hydroxy-7-cis-tetradecenoyl)homoserine lactone (3OH, C(14:1)-HSL), a molecule previously known as the Rhizobium leguminosarum small bacteriocin as a consequence of its growth inhibitory properties, (ii) N:-decanoylhomoserine lactone (C(10)-HSL) and (iii) N:-hexanoylhomoserine lactone (C(6)-HSL). A gene (hdtS) capable of directing synthesis of all three P. fluorescens AHLs in Escherichia coli was cloned and sequenced. In vitro transcription/translation of hdtS yielded a protein of approximately 33 kDa capable of directing the synthesis of 3OH, C(14:1)-HSL, C(10)-HSL and C(6)-HSL in E. coli. HdtS does not belong to either of the known AHL synthase families (LuxI or LuxM) and is related to the lysophosphatidic acid acyltransferase family. HdtS may therefore constitute a member of a third protein family capable of AHL biosynthesis.
Laue
Bridget E
BE
School of Pharmaceutical Sciences, University of Nottingham, Nottingham NG7 2RD, UK1.
Jiang
Yan
Y
School of Pharmaceutical Sciences, University of Nottingham, Nottingham NG7 2RD, UK1.
Chhabra
Siri Ram
SR
School of Pharmaceutical Sciences, University of Nottingham, Nottingham NG7 2RD, UK1.
Jacob
Sinead
S
Biomerit Research Centre, Department of Microbiology, National University of Ireland, Cork, Ireland2.
Stewart
Gordon S A B
GSAB
School of Pharmaceutical Sciences, University of Nottingham, Nottingham NG7 2RD, UK1.
Hardman
Andrea
A
School of Pharmaceutical Sciences, University of Nottingham, Nottingham NG7 2RD, UK1.
Downie
J Allan
JA
John Innes Centre, Colney, Norwich NR4 7UH, UK3.
O'Gara
Fergal
F
Biomerit Research Centre, Department of Microbiology, National University of Ireland, Cork, Ireland2.
Williams
Paul
P
School of Pharmaceutical Sciences, University of Nottingham, Nottingham NG7 2RD, UK1.
D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000378:metabolism; D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D006714:Homoserine / Q000031:analogs & derivatives* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010572:Pest Control, Biological / Q000379:methods; D011551:Pseudomonas fluorescens / Q000201:enzymology* / Q000235:genetics
D001426:Bacterial Proteins; C117255:N-(3-hydroxy-7-tetradecanoyl)homoserine lactone; C088386:homoserine lactone; D006714:Homoserine; D000217:Acyltransferases; C417342:HdtS protein, Pseudomonas fluorescens F113; D015107:4-Butyrolactone