Antagonismo in vitro entre actinobactérias e rizóbios do solo de região semiárida brasileira

Abstract

Studies of bacteria interacting with the environment has historically been focused on strategies to obtain nutrients and resist abiotic stresses. The interbacterial antagonism approach is increasingly highlighted in the scientific literature. Among soil bacteria with potential for interactive studies are actinobacteria and rhizobium. The Brazilian northeast semi-arid is an interesting habitat for these researches mainly due to the extreme characteristics of climate and soil of the region and thus encouraging competition between the organisms present there. The main goal of this research was to evaluate the in vitro antagonism between strains of actinobacteria and rhizobia from soils of the Brazilian semi-arid region. The bacteria strain’s used in the research were evaluated using the PAST software for normality tests, ANOVA and multivariate analysis of variance (MANOVA) with a p-value of 0.05. Eleven strains of actinobacteria from soils from Aiuaba - CE, Ubajara - CE and Sete Cidades-PI and seven strains of rhizobium from Quixadá and Cascavel,both located in Ceará, were selected. Yeast – Mannitol - Agar medium was used to visualize the halos of inhibitory effects of actinobacteria. The results revealed that strains A125, A146, A148 and A150 showed inhibitory effects against diazotrophic bacteria, indicating that 36% of the tested strains of actinobacteria showed the production of an inhibitory compound for rhizobia. This study demonstrated the antagonistic activity of actinobacteria against diazotrophic bacteria.