Temperature-dependent biofilm and sublancin production immobilise arsenic and antibiotic resistance gene mobility in soil system

Abstract Climate change-induced warming and arsenic soil contamination synergistically threaten agricultural sustainability by restructuring microbial communities and accelerating antibiotic resistance evolution. Here, we demonstrate that Bacillus subtilis 168-derived sublancin, a temperature-optimised glycosylated antimicrobial peptide, simultaneously maximises microbial arsenic sequestration and suppresses antibiotic resistance gene (ARG) horizontal transfer. Temperature-dependent biofilm formation increased progressively from 25–35°C (absorbance: 0.37–1.2), correlating with enhanced arsenic accumulation within the extracellular polymeric substance matrix (74% increase in weight percentage). Time-of-flight secondary ion mass spectrometry confirmed maximum arsenic sequestration at 35°C (total counts: 4.725×10⁴). Sublancin production peaked at 30.8°C (129.72 mg/L) and significantly reduced soil microbial biomass carbon by 33% (p < 0.001), with selective suppression of Gram-positive bacteria (42%–28% survival reduction). Conjugation assays revealed sublancin bio-amendment dramatically suppressed horizontal ARG transfer, reducing HGT frequency by 74.7% (6.64 × 10⁻³ to 1.68 × 10⁻³, p < 0.001) through dual mechanisms: decreased donor viability and reduced conjugation efficiency. Gene ontology enrichment identified coordinated upregulation of exopolysaccharide synthesis (FDR ~1.0×10⁻²⁷), phosphotransferase systems, and arsenic resistance pathways, alongside downregulation of conventional antibiotic resistance genes. These findings establish sublancin as a dual-function soil amendment simultaneously addressing two critical agricultural threats: heavy metal bioaccumulation and antibiotic resistance dissemination under climate warming.