Prospecting the Functional Potential of Bacillus altitudinis 1.4 Isolated from Sediment in Association with Bradyrhizobium japonicum.

Abstract

Bacteria of the genus Bacillus are ubiquitous in nature and produce several antimicrobial compounds, being increasingly used in plant biocontrol. The objective of this study was to identify the isolate Bacillus sp. 1.4 at the species level and study its bioactive properties prospecting the potential for agricultural application. The bacterial isolate was identified as belonging to Bacillus altitudinis through genomic metrics. The antimicrobial substance extracted with butanol inhibited Listeria monocytogenes ATCC 7644 and Bradyrhizobium japonicum CT 00345 with inhibition halos of 16 and 13 mm, respectively. In the exopolysaccharide production assay, B. altitudinis 1.4 presented a negative result and in the assessment of motility through the swarming assay, 90 mm halos were observed in both agar concentrations (0.3 and 0.7%) for up to 72 h of incubation. Genomic analysis revealed genes potentially encoding traits that could be beneficial to plants, such as phytohormone and siderophores production, polyamine metabolism, biofilm formation, exopolysaccharide, and motility. These characteristics may be important to improve the competition of B. altitudinis 1.4 in the soil. This bacterium was able to solubilize inorganic phosphate, coexist with B. japonicum CT 00345 and form biofilm. Based on the results found and with new tests to be carried out, it is suggested that the isolate B. altitudinis1.4 could be a candidate for plant growth promoter.