Transcriptomic Analyses Elucidate Adaptive Differences of Closely Related Strains of Pseudomonas aeruginosa in Fuel.
Pseudomonas aeruginosacan utilize hydrocarbons, but different strains have various degrees of adaptation despite their highly conserved genome.P. aeruginosaATCC 33988 is highly adapted to hydrocarbons, whileP. aeruginosastrain PAO1, a human pathogen, is less adapted and degrades jet fuel at a lower rate than does ATCC 33988. We investigated fuel-specific transcriptomic differences between these strains in order to ascertain the underlying mechanisms utilized by the adapted strain to proliferate in fuel. During growth in fuel, the genes related to alkane degradation, heat shock response, membrane proteins, efflux pumps, and several novel genes were upregulated in ATCC 33988. Overexpression ofalkgenes in PAO1 provided some improvement in growth, but it was not as robust as that of ATCC 33988, suggesting the role of other genes in adaptation. Expression of the function unknown gene PA5359 from ATCC 33988 in PAO1 increased the growth in fuel. Bioinformatic analysis revealed that PA5359 is a predicted lipoprotein with a conserved Yx(FWY)xxD motif, which is shared among bacterial adhesins. Overexpression of the putative resistance-nodulation-division (RND) efflux pump PA3521 to PA3523 increased the growth of the ATCC 33988 strain, suggesting a possible role in fuel tolerance. Interestingly, the PAO1 strain cannot utilizen-C8andn-C10The expression of green fluorescent protein (GFP) under the control ofalkBpromoters confirmed thatalkgene promoter polymorphism affects the expression ofalkgenes. Promoter fusion assays further confirmed that the regulation ofalkgenes was different in the two strains. Protein sequence analysis showed low amino acid differences for many of the upregulated genes, further supporting transcriptional control as the main mechanism for enhanced adaptation.IMPORTANCEThese results support that specific signal transduction, gene regulation, and coordination of multiple biological responses are required to improve the survival, growth, and metabolism of fuel in adapted strains. This study provides new insight into the mechanistic differences between strains and helpful information that may be applied in the improvement of bacterial strains for resistance to biotic and abiotic factors encountered during bioremediation and industrial biotechnological processes.
Environmental Microbiology Group, University of Dayton Research Institute, University of Dayton, Dayton, Ohio, USA.
Thusitha S
TS
Gunasekera
Environmental Microbiology Group, University of Dayton Research Institute, University of Dayton, Dayton, Ohio, USA.
Loryn L
LL
Bowen
Lawrence Livermore National Laboratory, Livermore, California, USA.
Carol E
CE
Zhou
Environmental Microbiology Group, University of Dayton Research Institute, University of Dayton, Dayton, Ohio, USA.
Susan C
SC
Howard-Byerly
Fuels and Energy Branch, Aerospace Systems Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio, USA.
William S
WS
Foley
Environmental Microbiology Group, University of Dayton Research Institute, University of Dayton, Dayton, Ohio, USA.
Richard C
RC
Striebich
Lawrence Livermore National Laboratory, Livermore, California, USA.
Larry C
LC
Dugan
Fuels and Energy Branch, Aerospace Systems Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio, USA Oscar.Ruiz@us.af.mil.
Oscar N
ON
Ruiz
D020816:Amino Acid Motifs; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D006838:Hydrocarbons / Q000737:chemistry / Q000378:metabolism*; D015394:Molecular Structure; D011401:Promoter Regions, Genetic; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*
D001426:Bacterial Proteins; D006838:Hydrocarbons; C029662:JP5 jet fuel
GFP; Pseudomonas aeruginosa; biodegradation; biofilms; efflux pumps; genomics; jet fuel; microarray; stress response; transcriptome