Propriedade antifúngica de extrato protéico de folhas do abacaxizeiro

Abstract

Although Ananas comosus (L.) Merr. is a fruit tree that has a great economic importance in Brazil it faces some limitations mainly in agriculture illness especially those that are caused by fungi. Thus, a fusariosis resistant genotype (EC-099) was selected by INCAPER. Nevertheless resistant factor of this plant is not clear yet. So, extract proteins from chlorophylls tissues of the plant leafs and test their activities against fungi of economic interest. Protein extraction was made followed by the separation by molecular weight trough precipitation with ammonium sulfate resulting in fractions 0-20% (F1), 20- 50% (F2) and 50-75% (F3) p/v. The antifungal activity was evaluated during 4 days through in spectrophotometer analysis by determination of fungi growth Aspergilus niger, Beauveria bassiana, Colletotrichum gloesporioides, Colletotrichum musae, Chalara paradoxa, Cladosporium sp., Fusarium subglutinanas f. sp. ananas (E-261) resistant and proneness to the fungicidal Benomyl, Penicilium sp. e Trichophyton rubrum grown in a potato dextrose (BD) liquid medium, inoculated with 1,5x106 spores/ml. Concentrations of 0; 0,05; 0,1; 0,2; 0,3; 0,4 and 0,5 mg/ml of each fraction were tested. F1 inhibited growth of all tested fungi that were, obtaining the minor media and differing statistically from the other fractions when tested against A. niger, C. gloesporioides, C. musae, Cladosporium sp., F. subglutinanas f. sp. ananas, Penicilium sp. and T. rubrum. The development of C. paradoxa was ~ 30% inhibited by the three fractions, and had no significant difference among them. The F2 and F3 fractions presented a higher specificity to A. niger and Cladosporium sp. However, F2 and F3 were not efficient to inhibit the growth of F. subglutinanas f. sp. ananas ( less them 20%). F3 inhibited the A. niger growth up to 42,9%. By the regression analysis a better inhibition’s linearity by F1 was observed, obtaining higher values of the coefficient of correlation linear, when compared with F2 and F3, excepted to fungi B. bassiana e C. paradoxa. The results obtained in the tests demonstrated the existence of proteins with antifungal action in the resistant genotype of the pineapple tree (EC-099) and F1 presented higher efficiency in fungal inhibition. Thus, we may deduce that these proteins might be associated with the resistance of this genotype to fusariosis. Furthermore, the results demonstrate the existence of proteins with a high specter of action against different lends of fungi, indicating that this is an important object of research in genetic and in pharmacological industry.