Abstract

MACEDO CASTILLO, Aracely; MARTINEZ HERNANDEZ, Aida  and  LARA REYNA, Joel. Quantitative Evaluation and Molecular Identification of Rhizobateria from Tropical Region, Antagonistic Against Colletotrichum gloeosporioides. Rev. mex. fitopatol [online]. 2012, vol.30, n.1, pp.11-30. ISSN 2007-8080.

A total of 278 bacterial isolates from the rhizosphere of tropical crops were evaluated for its potential to inhibit in vitro the growth of Colletotrichum gloeosporioides. From these, 31 isolates showed antagonistic activity. Dual confrontation qualitative tests for the 31 isolates resulted in the selection of eight isolates antagonist for C. gloeosporioides. To evaluate quantitatively the growth inhibition of C. gloeosporioides, we established a method by standarizing the initial inoculum of the antagonistic bacteria and the pathogen while scanning on a daily basis the growth area of both organisms either growing under confrontation or without antagonism. This method allowed the comparison of the ability of inhibition of each strain against a commercial strain by measuring the fungus growth area, the maximum growth of the colonies, the initiation of the antagonism, the average of the daily growth rate of the fungus, the percentage of inhibition, and the inhibition zone in each confrontation. All together, the method allowed an objective determination of the potential as antagonist agents of each isolate. Furthermore the eight isolates were molecularly identified by sequencing the ribosomal gene 16S rRNA, resulting in the identification of genera belonging to Bacillus and Burkholderia.

Keywords : ribosomal gene; 16S rRNA; Bacillus; Burkholderia.

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