In Vitro Coinoculation Between Actinobacteria and Diazotrophic Nodulating Bacteria from the Semiarid

Purpose: To evaluate the potential of actinobacterial strains from the Brazilian semiarid to establish facilitation relationships with native rhizobia from the same region. Theoretical framework: The study is based on the ecological and biotechnological importance of soil actinobacteria, producers of biosurfactants and enzymes, and of nitrogen-fixing rhizobia in legumes. Method: 50 strains of actinobacteria were isolated from soils from Ceará with different levels of anthropization and 19 strains of rhizobia using cowpea. The morphological, cultural and micromorphological characterization of the strains was performed, as well as the evaluation of their enzymatic profiles. In vitro facilitation tests were conducted between cellulolytic actinobacteria and non-cellulolytic rhizobia. Results: The soil areas presented a similar composition of actinobacteria, but strains from the anthropized area showed higher enzymatic activity. Two Streptomyces strains promoted the growth of non-cellulolytic rhizobia in vitro, indicating potential application as bioinoculants in microbial consortia. Conclusions: The study contributes to the knowledge of the interaction between beneficial microbial groups from the semiarid region and their possible biotechnological use in agriculture. Originality/value: Works on coinoculation between actinobacteria and rhizobia from semiarid soils are scarce.