Caracterization of a thaumatin-like gene expressed by Moniliophthora Perniciosa fungus, the causative agent of cacao Whiches Broom disease / Caracterização de um gene similar a taumatina expresso pelo fungo causador da Vassoura de bruxa, Moniliophthora perniciosa

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Moniliophthora perniciosa is a phytopatogen that has economical importance in Brazil, particularly in the south of Bahia, because this fungus causes the disease in cacao known as Witches Broom disease. This fungus is a hemibiotrofic pathogen that has two distinct stages: a biotrophic (or parasitic) and a necrotrophic (or saprotrophic). The database generated by the Witches Broom genome project has been studied in order to unravel the metabolic pathways used by the pathogen during the colonization of cacao. Curiously, it was detected the expression of a gene similar to thaumatins in M. perniciosa. Plant thaumatins are expressed during hypersensitive responde (HR) in plant pathogen interactions, being classified as PR-5 (pathogenicity related protein class-5). Thaumatins have antifungal and ß-glucanolitic activities. Recently, a new wheat thaumatin-like protein was described as a xylanase inhibitor. Thaumatins from nematodes, arthropods and fungi have also been characterized. This work aimed the cloning of the M. perniciosa thaumatin like-gene MpTLP1, the expression of the recombinant protein MpTLP1, as well as at the characterization of its gene expression during the development of M. perniciosa. Northern blot analysis shows that MpTLP1 expression is induced when the fungus is incubated with cacao extract and salicylic acid. Real time-PCR data show that MpTLP1 is more expressed in the biotrophic stage of the fungus. These results suggest the participation of MpTLP1 in plant-pathogen interaction. MpTLP1 was expressed in E. coli and refolded from inclusion bodies. The refolded protein did not have antifungal or ß- glucanolytic activity. These results can be attributed to an inefficient refolding or to structural differences in relation to other TLPs that have antifungal and ß- glucanolytic activity. Some MpTLP1 features may indicate that this protein inhibits xylanases or other enzymes that cleave cell walls

ASSUNTO(S)

whiches broom disease taumatina moniliophthora perniciosa vassoura-de-bruxa (fitopatologia) thaumatin moniliophthora perniciosa

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