title: Characterization of a novel NADP(+)-dependent D-arabitol dehydrogenase from the plant pathogen Uromyces fabae.
abstract: We have identified and characterized a novel NADP(+)-dependent D-arabitol dehydrogenase and the corresponding gene from the rust fungus Uromyces fabae, a biotrophic plant pathogen on broad bean (Vicia faba). The new enzyme was termed ARD1p (D-arabitol dehydrogenase 1). It recognizes D-arabitol and mannitol as substrates in the forward reaction, and D-xylulose, D-ribulose and D-fructose as substrates in the reverse reaction. Co-factor specificity was restricted to NADP(H). Kinetic data for the major substrates and co-factors are presented. A detailed analysis of the organization and expression pattern of the ARD1 gene are also given. Immunocytological data indicate a localization of the gene product predominantly in haustoria, the feeding structures of these fungi. Analyses of metabolite levels during pathogenesis indicate that the D-arabitol concentration rises dramatically as infection progresses, and D-arabitol was shown in an in vitro system to be capable of quenching reactive oxygen species involved in host plant defence reactions. ARD1p may therefore play an important role in carbohydrate metabolism and in establishing and/or maintaining the biotrophic interaction in U. fabae.
authors.affiliation: Fachbereich Biologie, Universität Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Link
authors.forename: Gertrud
authors.initials: G
authors.lastname: Lohaus
authors.forename: Ingrid
authors.initials: I
authors.lastname: Heiser
authors.forename: Kurt
authors.initials: K
authors.lastname: Mendgen
authors.forename: Matthias
authors.initials: M
authors.lastname: Hahn
authors.forename: Ralf T
authors.initials: RT
authors.lastname: Voegele
mesh_terms: D001487:Basidiomycota / Q000201:enzymology*; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D007700:Kinetics; D008969:Molecular Sequence Data; D010429:Pentoses / Q000378:metabolism; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000378:metabolism / Q000382:microbiology; D013401:Sugar Alcohol Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D013402:Sugar Alcohols / Q000378:metabolism; D031307:Vicia faba / Q000382:microbiology; D014996:Xylulose / Q000378:metabolism
chemical_list: D010429:Pentoses; D013402:Sugar Alcohols; C100182:ribulose; D014996:Xylulose; D013401:Sugar Alcohol Dehydrogenases; C022751:D-arabinitol dehydrogenase; C014999:arabitol