title: Mapping the Sinorhizobium meliloti 1021 solute-binding protein-dependent transportome.
abstract: The number of solute-binding protein-dependent transporters in rhizobia is dramatically increased compared with the majority of other bacteria so far sequenced. This increase may be due to the high affinity of solute-binding proteins for solutes, permitting the acquisition of a broad range of growth-limiting nutrients from soil and the rhizosphere. The transcriptional induction of these transporters was studied by creating a suite of plasmid and integrated fusions to nearly all ATP-binding cassette (ABC) and tripartite ATP-independent periplasmic (TRAP) transporters of Sinorhizobium meliloti. In total, specific inducers were identified for 76 transport systems, amounting to approximately 47% of the ABC uptake systems and 53% of the TRAP transporters in S. meliloti. Of these transport systems, 64 are previously uncharacterized in Rhizobia and 24 were induced by solutes not known to be transported by ABC- or TRAP-uptake systems in any organism. This study provides a global expression map of one of the largest transporter families (transportome) and an invaluable tool to both understand their solute specificity and the relationships between members of large paralogous families.
authors.affiliation: School of Biological Sciences, University of Reading, Reading RG6 6AJ, United Kingdom.
authors.forename: T H
authors.initials: TH
authors.lastname: Mauchline
authors.forename: J E
authors.initials: JE
authors.lastname: Fowler
authors.forename: A K
authors.initials: AK
authors.lastname: East
authors.forename: A L
authors.initials: AL
authors.lastname: Sartor
authors.forename: R
authors.initials: R
authors.lastname: Zaheer
authors.forename: A H F
authors.initials: AH
authors.lastname: Hosie
authors.forename: P S
authors.initials: PS
authors.lastname: Poole
authors.forename: T M
authors.initials: TM
authors.lastname: Finan
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D000143:Acids / Q000378:metabolism; D000588:Amines / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport / Q000502:physiology; D002241:Carbohydrates; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D008969:Molecular Sequence Data; D009876:Operon; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011687:Purines / Q000378:metabolism; D011743:Pyrimidines / Q000378:metabolism; D016962:Sinorhizobium meliloti / Q000235:genetics / Q000378:metabolism*
chemical_list: D018528:ATP-Binding Cassette Transporters; D000143:Acids; D000588:Amines; D000596:Amino Acids; D001426:Bacterial Proteins; D002241:Carbohydrates; D011687:Purines; D011743:Pyrimidines