Avaliação de bactérias isoladas de milho (Zea mays) e de camarão (Litopenaeus vannamei) quanto ao potencial de antagonizar patógenos desta planta

Abstract

Maize is one of the cereals most important in the world and Brazilian agricultural scenario. However, like many other crops it is necessary to add high doses of chemical inputs as fertilizers or pesticides. The large area planted together management techniques that favor the permanence of pathogenic microorganisms in the soil, has contributed to increase the incidence of diseases. Among the phytopathogens of maize can be mentioned the fungi Colletotrichum graminicola, Fusarium verticilioides and Stenocarpella maydis and the bacterium Pantoea ananatis. The search of strategies to combat these microorganisms is highly encouraged and one of the possible methods is biological control using bacteria that antagonize these phytopathogens. Thus, the objective of this work was to evaluate the potential of endophytic bacteria isolated of maize and others isolated from the gastrointestinal tract of shrimp species to antagonize these phytopathogens, as well as to investigate the surfactant / emulsifying properties of the molecules produced by these antagonistic bacteria. Of the 36 bacterial isolates evaluated against fungal phytopathogens, P. ananatis and positive gram bacteria B. Subtilis in the antagonism test by pairing was observated that 31 bacterias had antagonistic activity against the pathogen C. graminicola, 32 antagonized S. maydis and 17 were positive in the antagonism against the F. verticilioides fungus. The genus Bacillus stood out among the best results of the antagonistic bacteria and F. Verticilioides was the most resistant pathogen. Some of the bacteria, like RT2C-11, BC6, BC 9 and BC 5 are in the groups of best antagonists for all the phytopathogens and presented in their extracts compounds with high emulsifying activity. So, this results suggest the use of these bacteria in plant inoculation experiments for validation of the potential of these bacteria as agents of biological control.