Cloning and characterization of the gene encoding nitrate reductase in Colletotrichum lindemuthianum, a bean (Phaseolus vulgaris) pathogen / Clonagem e caracterização do gene que codifica a nitrato redutase em Colletotrichum lindemuthianum, patógeno do feijoeiro (Phaseolus vulgaris)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The gene encoding nitrate reductase in Colletotrichum lindemuthianum, nit1, was isolated and characterized. Its nucleotide sequence and regulation in response to different nitrogen sources were analyzed. The gene nit1 has 2,787 base pairs (bp) bearing a single 696 bp intron starting at nucleotide 1,808. This intron is localized in a conserved region when compared to introns present in nitrate reductase genes of other fungi. Hovever, its similarity with them is restricted to the consensus splicing regions. Four TATC sequences, possibly related to binding of the general positive regulatory protein NIT2, were found in the upstream regulatory region of nit1, as well as other consensus sequences such as TATA and GC boxes. A putative binding site for NIT4, a specific regulatory protein, was also found in the 340 position. There is a putative mRNA polyadenilation site at the downstream 2,826 position. The protein translated from nit1 comprises 905 amino acid residues with a molecular mass of 101,1 kDa and presents high degree of identity with the cognate proteins in Metarhizium anisopliae (62,43 %), Magnaporte grisea (62,27%), Verticillium fungicola (60,15%), Botryotinia fuckchiana (58,30%), and Aspergillus fumigatus (51,93%). In mycelia cultivated in the presence of nitrate, nit1 was expressed after 15 min. Transcription was repressed in mycelia grown in medium containing either ammonium, urea, or glutamine. On glutamine, the level of transcription was apparently basal.

ASSUNTO(S)

gene nit1 nitrato redutase genetica molecular e de microorganismos colletotrichum lindemuthianum nitrate reductase colletotrichum lindemuthianum gene nit1

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