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| Status |
Public on Jun 17, 2013 |
| Title |
Expression analysis of the gacS mutant of Pseudomonas fluorescens SBW25 |
| Organism |
Pseudomonas [fluorescens] SBW25 |
| Experiment type |
Expression profiling by array
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| Summary |
Pseudomonas species are ubiquitous in plant-associated environments and produce an array of volatiles, enzymes and antimicrobials. The biosynthesis of many metabolites is regulated by the GacS/GacA two-component regulatory system. Transcriptome analysis of Pseudomonas fluorescens SBW25 revealed that 702 genes were differentially regulated (fold change>4, P<0.0001) in a gacS::Tn5 mutant, with 300 and 402 genes up- and down-regulated, respectively. Genes that were significantly down-regulated are involved in viscosin biosynthesis (viscABC), protease production (aprA), motility, biofilm formation, and secretory systems. Genes that were significantly up-regulated are involved in siderophore biosynthesis and oxidative stress. In contrast to previous studies with gac-mutants of other Pseudomonas species/strains, the gacS mutant of SBW25 inhibited growth of oomycete, fungal and bacterial pathogens significantly more than parental strain SBW25. A potential candidate for this enhanced antimicrobial activity was a large nonribosomal peptide synthetase (NRPS) gene cluster predicted to encode for an 8-amino-acid ornicorrugatin-like peptide. Site-directed mutagenesis of an NRPS gene in this cluster, however, did not lead to a reduction in the antimicrobial activity of the gacS mutant. Collectively these results indicate that a mutation in the GacS/GacA regulatory system causes major transcriptional changes in P. fluorescens SBW25 and significantly enhances its antimicrobial activities by yet unknown mechanisms.
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| Overall design |
This expression study used total RNA recovered from four separate wild-type cultures of Pseudomonas fluorescens SBW25 and four separate cultures of the gacS mutant. Expression design was based on the updated genome sequence of Pseudomonas fluorescens SBW25, NC_012660.1 and associated plasmid pQBR0476 with nineteen 60-mer probe per gene. Each probe is replicated 3 times. The design includes random GC and other control probes.
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| Contributor(s) |
Cheng X, de Bruijn I, van der Voort M, Raaijmakers JM |
| Citation(s) |
23864577 |
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| Submission date |
Jan 11, 2013 |
| Last update date |
Jul 24, 2013 |
| Contact name |
Xu Cheng |
| E-mail(s) |
xu.cheng@wur.nl
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| Organization name |
Wageningen University
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| Street address |
Droevendaalsesteeg 1
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| City |
Wageningen |
| ZIP/Postal code |
6708 PB |
| Country |
Netherlands |
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| Platforms (1) |
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| Samples (8)
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| Relations |
| BioProject |
PRJNA186425 |
| Supplementary file |
Size |
Download |
File type/resource |
| GSE43443_RAW.tar |
64.8 Mb |
(http)(custom) |
TAR (of TXT) |
| Processed data included within Sample table |
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