title: The plasma membrane H(+)-ATPase from the biotrophic rust fungus Uromyces fabae: molecular characterization of the gene (PMA1) and functional expression of the enzyme in yeast.
abstract: To study the molecular basis of biotrophic nutrient uptake by plant parasitic rust fungi, the gene (Uf-PMA1) encoding the plasma membrane H(+)-ATPase from Uromyces fabae was isolated. Uf-PMA1 exists probably as a single gene. However, two nearly identical sequences were identified; the similarity apparently is due to two Uf-PMA1 alleles in the dikaryotic hyphae. Multiple Uf-PMA1 transcripts were observed during early rust development, and reduced amounts of a single Uf-PMA1 mRNA were observed in haustoria and rust-infected leaves. This is in contrast to elevated enzyme activity in haustoria compared to germinated spores (C. Struck, M. Hahn, and K. Mendgen. Fungal Genet. Biol. 20:30-35, 1996). Unexpectedly, the PMA1-encoded rust protein is more similar to H(+)-ATPases from plants (55% identity) than from ascomycetous fungi (36% identity). When the rust PMA1 cDNA was expressed in Saccharomyces cerevisiae, both the wild-type enzyme and a mutant derivative (delta 76) deleted for the 76 C-terminal amino acids were able to support growth of a yeast strain lacking its own H(+)-ATPases. Compared to the wild-type, the delta 76 mutant enzyme displayed increased affinity to ATP, a higher vanadate sensitivity, and a more alkaline pH optimum. These results indicate that the C-terminal region of the rust enzyme exhibits auto-regulatory properties.
authors.affiliation: Fakultät für Biologie, Universität Konstanz, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Struck
authors.forename: C
authors.initials: C
authors.lastname: Siebels
authors.forename: O
authors.initials: O
authors.lastname: Rommel
authors.forename: M
authors.initials: M
authors.lastname: Wernitz
authors.forename: M
authors.initials: M
authors.lastname: Hahn
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D001487:Basidiomycota / Q000201:enzymology*; D002462:Cell Membrane / Q000201:enzymology; D003001:Cloning, Molecular; D018076:DNA, Complementary; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D006180:Proton-Translocating ATPases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics
chemical_list: D018076:DNA, Complementary; D006180:Proton-Translocating ATPases