title: Disruption of Transporters Affiliated with Enantio-Pyochelin Biosynthesis Gene Cluster of Pseudomonas protegens Pf-5 Has Pleiotropic Effects.
abstract: Pseudomonas protegens Pf-5 (formerly Pseudomonas fluorescens) is a biocontrol bacterium that produces the siderophore enantio-pyochelin under conditions of iron starvation in a process that is often accompanied by the secretion of its biosynthesis intermediates, salicylic acid and dihydroaeruginoic acid. In this study, we investigated whether several transporters that are encoded by genes within or adjacent to the enantio-pyochelin biosynthetic cluster, serve as efflux systems for enantio-pyochelin and/or its intermediates. In addition, we determined whether these transporters have broad substrates range specificity using a Phenotype Microarray system. Intriguingly, knockouts of the pchH and fetF transporter genes resulted in mutant strains that secrete higher levels of enantio-pyochelin as well as its intermediates salicylic acid and dihydroaeruginoic acid. Analyses of these mutants did not indicate significant change in transcription of biosynthetic genes involved in enantio-pyochelin production. In contrast, the deletion mutant of PFL_3504 resulted in reduced transcription of the biosynthetic genes as well as decreased dihydroaeruginoic acid concentrations in the culture supernatant, which could either point to regulation of gene expression by the transporter or its role in dihydroaeruginoic acid transport. Disruption of each of the transporters resulted in altered stress and/or chemical resistance profile of Pf-5, which may reflect that these transporters could have specificity for rather a broad range of substrates.
authors.affiliation: Department of Chemistry and Biomolecular Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, New South Wales, Australia.
authors.forename: Chee Kent
authors.initials: CK
authors.lastname: Lim
authors.affiliation: Department of Chemistry and Biomolecular Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, New South Wales, Australia.
authors.forename: Anahit
authors.initials: A
authors.lastname: Penesyan
authors.affiliation: Department of Chemistry and Biomolecular Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, New South Wales, Australia.
authors.forename: Karl A
authors.initials: KA
authors.lastname: Hassan
authors.affiliation: USDA-ARS Horticultural Crops Research Laboratory and Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: Joyce E
authors.initials: JE
authors.lastname: Loper
authors.affiliation: Department of Chemistry and Biomolecular Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, New South Wales, Australia.
authors.forename: Ian T
authors.initials: IT
authors.lastname: Paulsen
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics*; D019295:Computational Biology / Q000379:methods; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D055786:Gene Knockout Techniques; D026901:Membrane Transport Proteins / Q000235:genetics*; D005810:Multigene Family; D011549:Pseudomonas / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism; D013844:Thiazoles / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D013844:Thiazoles; C055755:2'-(2-hydroxyphenyl)-2'-thiazoline-4'-carboxylic acid; D020156:Salicylic Acid