Bacteria from savanna–like Cerrado soils tolerant of pH and salinity and antagonistic to Ralstonia solanacearum

Marques E.; Uesugi C H.

Volume : VII, Issue : X, October - 2017

Bacteria from savanna–like Cerrado soils tolerant of pH and salinity and antagonistic to Ralstonia solanacearum

Marques E. , Uesugi C H.

Abstract :

Microorganisms that inhabit the soil play several ecological functions, such as organic matter decomposition, particle aggregation and biological control. The objective of this study was to verify the presence of bacteria tolerant of temperature, pH and salinity in savanna–like Cerrado soils, besides evaluating their antagonistic potential to Ralstonia solanacearum, the causal agent of bacterial wilt of various plant species. Sixty–one bacterial isolates were obtained, and 30 of them (none at high temperatures) showed any in vitro antagonism against the plant pathogen in question. Among these, 10 isolates were selected for characterization and identification by sequencing of 16S rRNA. The cultural and morphological characteristics and tests performed were corroborated by the sequencing, which led to the identification of two bacterial genera: Enterobacter and Bacillus. Enterobacter sp. were obtained from pH 5 and 7. On the other hand, Bacillus sp. were obtained from pH 3, 5, 9, 10 and 10 and 15% of NaCl. Both bacterial genera observed in savanna–like Cerrado soils are already recognized for their physiological versatility and occurrence in different habitats, as well as their importance in the biological control of pests and pathogens or in the promotion of plant growth, which indicates that the soils of this region are also important sources of microorganisms for the most diverse purposes. These bacterial isolates are stored in the Collection of Bacteria from the Department of Plant Pathology of the University of Brasilia and are available for future studies.