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While Paenibacillus polymyxa is widely recognized for its biocontrol capabilities, most characterized strains originate from soil or rhizosphere environments, leaving animal-associated populations largely unexplored. In this study, we report the isolation of P. polymyxa strain CACC1094 from the bovine rumen and its genome-guided characterization to investigate its biosynthetic potential and antifungal activity. Whole-genome sequencing yielded a complete circular chromosome of 5.55 Mb with a GC content of 45.36%, comprising 5,099 coding sequences, 39 rRNA genes, and 111 tRNA genes. Comparative phylogenomic analysis placed CACC1094 within the P. polymyxa species complex, clustering most closely with the rumen-associated strain ND24 (ANI: 98.31%) and strain 188 (ANI: 96.92%), while forming a distinct branch within the species. Genome mining identified 13 biosynthetic gene clusters, including those associated with fusaricidin and tridecaptin biosynthesis, a paenicidin-like lanthipeptide cluster, and a hybrid NRPS–PKS cluster. In dual-culture assays, CACC1094 showed broad in vitro antifungal activity against multiple plant-pathogenic fungi and oomycetes, as well as selected fungal and yeast pathogens of clinical and veterinary relevance. LC-QTOF/MS analysis of culture supernatants confirmed the production of fusaricidin A and fusaricidin B, providing direct experimental validation of genome-derived predictions. Additionally, genome annotation revealed a complete CRISPR-Cas adaptive immune system, suggesting an integrated ecological strategy that combines antimicrobial biosynthesis with defense against mobile genetic elements. Together, these findings identify CACC1094 as a rumen-associated P. polymyxa strain with broad-spectrum antifungal activity and experimentally validated fusaricidin production, highlighting its potential as a source of antifungal metabolites for agricultural and veterinary applications.
Lee et al. (Thu,) studied this question.