Draft genome sequences of Bacillus pumilus 36R ATNSAL and B. safensis 13L LOBSAL, two potential candidate probiotic strains for shrimp aquaculture.

Objectives: This work aimed to isolate bacterial strains with antagonist activity against Vibrio parahaemolyticus, the causative agent of acute hepatopancreatic necrosis disease (VP) that was isolated from outbreaks in Mexico. Here, we report the draft genome sequences of two antagonistic strains, isolated from saline sediment in Sonora, Mexico.

Methods: Cross-streak and well diffusion tests were employed to find the bacterial strains with higher inhibitory activity against VP. The whole genomes of B. pumilus 36R ATNSAL and B. safensis 13L LOBSAL were sequenced using Ion Torrent (PGM) and Illumina Miseq platforms, respectively. Annotation was performed using the RAST server, and the genes involved in the biosynthesis of bacterial secondary metabolites were predicted using antiSMASH.

Results: Two bacterial isolates, B. safensis 13L LOBSAL and B. pumilus 36R ATNSAL, were chosen based on their strong antagonistic profiles. The genome of 36R ATNSAL was 3.94 Mbp in length and contained 3824 genes and a total of 4116 coding sequences (CDSs); the genome of 13L LOBSAL was 3.68 Mbp and contained 3619 genes and 3688 CDSs. Twenty-eight and 32 biosynthetic gene clusters responsible for putative antimicrobial metabolite production were identified in 36R ATNSAL and 13L LOBSAL, respectively.

Conclusions: The two strains 13L LOBSAL and 36R ATNSAL showed excellent probiotic profiles in vitro. The genome sequences will help with the mining and reconstruction of metabolic pathways in Bacillus strains. Genome sequence-guided strain improvement could augment the probiotic potential of Bacillus strains for applications in shrimp aquaculture.