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 (VPAHPND) 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 VPAHPND. The whole genomes of B. pumilus 36R ATNSAL and B. safensis 13L LOBSAL were sequenced using Ion TorrentTM (PGM) and Illumina MiseqTM 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.

Draft genome sequence of Pseudoalteromonas piscicida strain 36Y_RITHPW, a hypersaline seawater isolate from the south coast of Sonora, Mexico.

OBJECTIVES: This study reports the draft genome sequence of Pseudoalteromonas piscicida strain 36Y_RITHPW, a marine Gammaproteobacteria that synthesises bioactive compounds with antagonistic activity against Vibrio parahaemolyticus, a multidrug-resistant strain that is the causative agent of acute hepatopancreatic necrosis disease (AHPND), reported in shrimp farm outbreaks from Asia to Mexico with mortality rates of 80-100%. METHODS: The genome of P. piscicida 36Y_RITHPW was sequenced with an Ion Torrent™ Personal Genome Machine™ (PGM) platform. A total of 606805 reads were constructed for a 308.48Mbp and 33.5×coverage. A high-quality draft assembly and ordering of contigs was obtained with Mauve. The annotation was obtained with RAST and antiSMASH. RESULTS: The genome size consists of 5.15Mbp, with a total of 4548 genes, 4217 protein-coding sequences and a GC content of 43.3%. Several resistance genes as well as other genes involved in the production of bacteriocins and ribosomally synthesised antibacterial peptides are also present. CONCLUSIONS: Mining of this draft genome provides valuable information to explain the antagonistic capacity of P. piscicida 36Y_RITHPW, a useful strain as a potential probiotic in shrimp aquaculture against pathogenic V. parahaemolyticus.