title: Structural and functional  characterization of the Colletotrichum lindemuthianum nit1 gene, which  encodes a nitrate eductase enzyme.
abstract: Colletotrichum lindemuthianum is the causal agent of plant bean anthracnose, one of the most important diseases affecting the common bean. We investigated the structure and expression of the nit1 gene (nitrate reductase) of C. lindemuthianum. The nit1 gene open reading frame contains 2787 bp, interrupted by a single 69-bp intron. The predicted protein has 905 amino acids; it shows high identity with the nitrate reductase of C. higginsianum (79%) and C. graminicola (73%). Expression of nit1 in C. lindemuthianum was evaluated in mycelia grown on different nitrogen sources under conditions of activation and repression. The gene was expressed after 15 min of induction with nitrate, reaching maximum expression at 360 min. The transcription was repressed in mycelia grown in media enriched with ammonia, urea or glutamine. Twenty nit1⁻ mutants were obtained in a medium treated with chlorate. Ten of these mutants were characterized by DNA hybridization, which identified point mutations, a deletion and an insertion. These rearrangements in the nit1 gene in the different mutants may have occurred through activity of transposable elements.
authors: Departamento de Microbiologia, Instituto de Biotecnologia Aplicada à  Agropecuária, Universidade Federal de Viçosa, Viçosa, MG, Brasil.
authors: G B
authors: GB
authors: Nogueira
authors: M V
authors: MV
authors: Queiroz
authors: R A
authors: RA
authors: Ribeiro
authors: E F
authors: EF
authors: Araújo
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D020231:Colletotrichum / Q000235:genetics*; D007438:Introns; D008969:Molecular Sequence Data; D009154:Mutation; D025282:Mycelium / Q000235:genetics; D050901:Nitrate Reductase / Q000235:genetics*; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D009693:Nucleic Acid Hybridization; D016366:Open Reading Frames; D010802:Phylogeny
chemical_list: D009566:Nitrates; D050901:Nitrate Reductase; D009584:Nitrogen