title: Expression profiling and functional analyses of BghPTR2, a peptide transporter from Blumeria graminis f. sp. hordei.
abstract: The obligate ascomycete parasitic fungus Blumeria graminis f. sp. hordei (Bgh) has a unique lifestyle as it is completely dependent on living barley leaves as substrate for growth. Genes involved in inorganic nitrogen utilization are notably lacking, and the fungus relies on uptake of host-derived peptides and amino acids. The PTR2 transporter family takes up di- and tri- peptides in a proton coupled process and filamentous fungi typically have two or more di/tri peptide transporters. Here we show that Bgh appear to have one PTR2 that can restore dipeptide uptake in a Saccharomyces cerevisiae PTR2 deletion strain. The Bgh PTR2 gene is expressed in conidia and germinating conidia. During Bgh infection of barley the expression level of the BghPTR2 gene is high in the appressorial germ tube, low in the haustoria and high again during conidiation and secondary infection in the compatible and intermediate resistant interactions. BghPTR2 appears to be important for the initial establishment of fungal infection but not for uptake of di-tri-peptides at the haustorial interface. Based on the expression profile we suggest that BghPTR2 is active in internal transport of nutrient reserves and/or uptake of break down products from the plant surface during the early infection stages.
authors.affiliation: Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg Ø, Denmark. Electronic address: ad@bio.aau.dk.
authors.forename: Aida
authors.initials: A
authors.lastname: Droce
authors.affiliation: Novo Nordisk A/S, Brennum Park, 3400 Hillerød, Denmark.
authors.forename: Kirsten B
authors.initials: KB
authors.lastname: Holm
authors.affiliation: Section for Genetics and Microbiology, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Copenhagen, Denmark.
authors.forename: Stefan
authors.initials: S
authors.lastname: Olsson
authors.affiliation: Section for Eukaryotic Biotechnology, Department of Systems Biology, Technical University of Denmark, Søltofts Plads, Build 223, 2800 Kgs. Lyngby, Denmark.
authors.forename: Rasmus J N
authors.initials: RJ
authors.lastname: Frandsen
authors.affiliation: Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg Ø, Denmark.
authors.forename: Teis Esben
authors.initials: TE
authors.lastname: Sondergaard
authors.affiliation: Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg Ø, Denmark.
authors.forename: Jens Laurids
authors.initials: JL
authors.lastname: Sørensen
authors.affiliation: Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg Ø, Denmark.
authors.forename: Henriette
authors.initials: H
authors.lastname: Giese
mesh_terms: D001203:Ascomycota / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D004151:Dipeptides / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D001467:Hordeum / Q000382:microbiology; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology; D013172:Spores, Fungal / Q000235:genetics / Q000378:metabolism
chemical_list: D004151:Dipeptides; D005656:Fungal Proteins; D026901:Membrane Transport Proteins; C043912:peptide permease
keywords: Barley powdery mildew; Gene expression; Obligate parasite; PTR2; Peptide transport; Yeast complementation