Lavin, ParisParisLavinChen, ZiAngZiAngChenWong, Clemente Michael Vui LingClemente Michael Vui LingWongTeoh, Chui PengChui PengTeohFierro-Vasquez, NataliaNataliaFierro-VasquezOses, RomuloRomuloOsesBanerjee, AparnaAparnaBanerjeeCabrera-Barjas, GustavoGustavoCabrera-BarjasPurcarea, CristinaCristinaPurcarea2026-07-072026-07-072026DIVERSITY-BASEL, 18(4), 236 (2026). https://doi.org/10.3390/d180402361424-2818https://hdl.handle.net/20.500.12740/24771The actinobacterial strain DEC002 was isolated recently from volcanic soils of Deception Island. Its taxonomic identity was resolved through a polyphasic strategy integrating morphology, physiological profiling, multilocus phylogeny, and genome-wide comparisons to resolve its identity. Concatenated core gene trees together with average nucleotide identity and digital DNA-DNA hybridization values place DEC002 within Actinacidiphila fildesensis with robust support. This is the first molecular confirmation of the species beyond King George Island and secures a second verified locality within the South Shetland Archipelago. Growth at low temperature with tolerance to moderate salinity indicates a psychrotolerant lifestyle. Cell-free supernatants inhibited representatives of foodborne Gram-negative and Gram-positive bacteria, including representatives of Enterobacteriaceae, Vibrio, Staphylococcus and Streptococcus. Genome analysis revealed enrichment in multiple biosynthetic gene clusters for nonribosomal peptides, polyketides, terpenes, and ribosomally synthesized and post-translationally modified peptides (RiPPs), supporting the biosynthetic potential of the strain. Functional annotations emphasize replication and repair modules, mobile element-associated proteins, helix-turn-helix regulators, and versatile transport systems, features coherent with cold stress and oligotrophic soils. Antibiotic susceptibility assays indicate a broad resistance phenotype under the experimental conditions tested, together with extracellular antimicrobial activity. These data refine the biogeography of A. fildesensis and indicate DEC002 as a credible Antarctic source of specialized metabolites with antimicrobial promise.info:eu-repo/semantics/openAccessActinacidiphilaAntarcticaDeception Islandgenomefunctional profileantimicrobial resistanceantimicrobial activityArticulohttps://doi.org/10.3390/d18040236