Comparative genomics analysis of Bacillus altitudinis G03 provides insights into its biocontrol and probiotic traits.

Background: Bacillus has been gradually applied to human production activities as a new type of biological control agent and probiotic preparation. This study investigates a newly isolated Bacillus altitudinis G03 utilizing whole genome sequencing, comparative genome analysis and in vitro experiments to comprehensively disclose its beneficial traits.

Results: According to whole genome sequencing and assembly data, the genome of G03 consists of a circular chromosome containing 10 gene clusters linked to the biosynthesis of secondary metabolites, 139 CAZymes, an antibiotic resistance gene, and 2 prophage elements, which show great potential in antibacterial and antifungal properties. G03 also encodes secreted proteins involved in important biological processes such as nutrient absorption, colonization, quorum sensing, and antibiotic synthesis. In vitro experiments confirm that G03 successfully inhibits the growth of several fungi and pathogenic bacteria, hydrolyzes protein and cellulose, and is capable of forming strong adhesive biofilms. Furthermore, comparative genomics analysis reveals that G03 contains 78 unique genes associated with various functions such as bacteriocin immunity and sporulation. Selective pressure analysis indicates that the genes associated with integral components of membrane and regulation of transcription are strongly positively selected, which may shape the evolution of G03.

Conclusions: Collectively, these results provide a strong theoretical framework for further research and utilization of B. altitudinis G03 as a novel probiotic and biocontrol agent.