Whole Genome Analysis of Propiconazole-Degrading Serratia marcescens BM-Q: A Rhizobacterium

Irrational application of propiconazole in agriculture poses serious environmental concerns due to its toxicity and persistence in soil. This study investigates the degradation potential of Serratia marcescens strain BM-Q and explores the key pathways involved in the degradation process through annotation and comparative analysis of whole genome. Strain BM-Q exhibited high tolerance to propiconazole (3000 µg/mL) and a decline in total soluble protein was observed in BM-Q under propiconazole stress, decreasing from 101.16 µg mL⁻¹ in the control to 41.53 µg mL⁻¹ at the 25× concentration. Gas chromatography analysis revealed that the concentration of propiconazole decreased from 100 mg/kg at day 0 to 69.06 mg/kg within 40 days, corresponding to 30.94% degradation by BM-Q, with a rate constant of 0.009 day⁻¹ and a half-life of 79.70 days. Whole genome sequencing indicated that the strain BM-Q harbors a 5.19 Mbp genome with 59.62% G + C content and 4,977 annotated genes, of which 178 are unique when compared with reference S. marcescens strains exhibiting potential to degrade various pesticides and hydrocarbons. Comparative genomic analysis results showed an average nucleotide identity of 99.32% with the S. marcescens strain MEW06. Genomic pathway analysis revealed that Serratia marcescens BM-Q harbors an extensive repertoire of catabolic genes involved in the degradation of diverse aromatic and xenobiotic compounds, indicating strong ecological adaptation and robust bioremediation potential. Strain BM-Q therefore exhibits low virulence potential and can be considered a non-pathogenic, low-risk candidate for environmental bioremediation. Our findings indicate that BM-Q can be a promising candidate for bioremediation of propiconazole-contaminated environments.