Caracterización y antagonismo in vitro de bacterias asociadas a frutos de cacao (theobroma cacao l.) en la provincia de Orellana.

Abstract

This investigation aimed to study the characterization and in vitro antagonism of bacteria associated with cocoa fruits (Theobroma cacao L.) Orellana province due to the diversity and antagonism potential of bacteria which is unknown. Samples from La Belleza, La Calumeña, INIAP EECA, Bajo Huiruno, Unión Milagreña and Tomebamba were processed. In the cultural characterization, aspects of the different colonies were determined and for the molecular characterization, DNA extraction was carried out using the OMEGA E.Z.N.A ® Bacterial DNA kit. Molecular identification was based on the analysis of 16S rRNA with primers 27f and 1492r and the PCR products were sequenced in the company MACROGEN COREA. For confrontations, the dual seeding technique was used, confronting Moniliophthora roreri as pathogen vs. 12 bacterial strains as antagonists in modified V8 culture medium and KADO 523 medium. The results obtained from the cultural characterization identified colonies with circular or irregular shape; whole, lobed, or wavy edge; flat elevation; white or yellow pigmentation and in molecular characterization they presented seven different genera. In confrontations, the highest percentage of inhibition was obtained by M.roreri of strain C10 from the Loreto canton, bacterium B40 and KADO 523 medium. It is concluded that Bacillus sp, Stenotrophomonas sp, Mammaliicococcus sp, Brucella sp, Achromobacter sp, Sphingobacterium sp and Brachybacterium sp. were present. The genus Bacillus sp is different in some places of Orellana province. Strain C10, Bacillus sp and Bacillus sp on KADO 523 medium were able to combat and limit the growth of the pathogen. It is recommended to use RNA polymerase (rpoB) sequences as an alternative tool for bacterial genotypic identification.