Descripción: |
Aims: Control of microbial pathogens by using antagonistic microorganisms is a promising
alternative to chemical fungicides. The objective of the present study was to isolate and
characterize soil actinomycetes and to their inhibitory activity against some fungal plant
pathogens.
Place and Duration of Study: National Park “El Chico”, Hidalgo State, and Laboratory of
the Southeast Unit of CIATEJ, Yucatán, México, between June 2010 and May 2011.
Methodology: Actinomycete species were isolated from six composite soil samples using
microbiological standard procedures. All isolates were phenotypically characterized.
Antagonistic isolates were selected according to the inhibitory growing of Fusarium sp. and
Candida albicans. Afterwards, a new evaluation for the isolates selected was done against
Helminthosporium sp., Curvularia sp., and Aspergillus niger. Actinomycetes were identified
performing an analysis of the 16S rDNA gene sequence.
Results: 164 actinomycete strains were characterized by morphological and biochemical
features. Six of them, inhibited the growth of Fusarium sp. and C. albicans from 5 to 10 mm
distance in between the actinomycete´s colony growth border of fungal or yeast. A growing
reduction from 50 to 83 % in the in vitro antagonism assays was observed for
Helminthosporium sp., Curvularia sp., and Aspergillus niger. Results in disc diffusion
assays suggested an inhibitory growing capacity of CACIA-1.46HGO for P. capsici, this
Short Communication
British Microbiology Research Journal, 4(3): 272-281, 2014
273
behavior could be due to the production of diffusible compounds related to secondary
metabolism, hydrolytic enzymes, or both of them. Four antagonistic isolates were identified
into Streptomyces genus and one as Microbacterium sp. through 16S rDNA gene
sequence.
Conclusion: Actinomycetes could be potentially a control tool to prevent several fungal
commercial plants diseases. However, in situ isolate evaluations are suggested to be
investigated |