Resumo

CASTILLO-REYES, Francisco et al. In vitro effectiveness of Bacillus and polyphenols of native plants from Mexico on Rhizoctonia-Solani. Rev. Mex. Cienc. Agríc [online]. 2015, vol.6, n.3, pp.549-562. ISSN 2007-0934.

In order to find alternatives for pathogen management causing diseases in the root system of plants, was evaluated the in vitro effect of antagonistic bacteria of the genus Bacillus isolated from rhizosphere and from ethanolic extracts of plants species Larrea tridentata, Flourensia cernua, Opuntia ficus-indica, Agave lechuguilla and Yucca filifera, that are endemic from the Chihuahua desert against plant pathogen Rhizoctonia solani. Bacteria were obtained as spore form; a soil suspension was heated for 15 min at 80 °C to remove non-sporulating forms. Plant extracts were obtained by infusion. As a result it was found that strains of Bacillus isolates have an in vitro antagonistic effect on mycelia inhibition of Rhizoctonia solani from 40 to 67%. The characterization 16S rDNA gene sequencing determined that the isolates belong to the species of B. subtilis, B. pumilus and B. atrophaeus, that are reported with antagonistic effect on plant pathogenic organisms. In the case of extracts, an effect on mycelial inhibition of up to 100% was found; most extracts inhibited micelial growth of R. solani at 100% except for Y. filifera extract that only obtained 46% with the highest dose evaluated (3 000 ppm). F. cernua extracts show that at 160 ppm of total polyphenols completely inhibited R. solani.

Palavras-chave : Rhizoctonia solani; antagonism; bacteria; extracts; mycelial inhibition; plant extract; rhizosphere.

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