Engineered E. coli Strains for Recombineering

The E. coli strains used in this study were DH5α (New England Biolabs) for cloning, bSLS.114^{18 (link)} for RT-DNA production, bMS.346^{15 (link)} for bacterial and phage retron recombineering assays. bSLS.114 was constructed from BL21-AI cells using lambda-red replacement to remove the retron-Eco1 locus. bMS.346 was generated from E. coli MG1655 by inactivating the exoI and recJ genes with early stop codons. Bacterial cultures were grown in LB (supplemented with 0.1 mM MnCl₂ and 5 mM MgCl₂ (MMB) for phage assays), shaking at 37 °C with appropriate inducers and antibiotics. Inducers and antibiotics were used at the following working concentrations: 1mM m-toluic acid (Sigma-Aldrich), 1 mM IPTG (GoldBio), 2 mg/ml L-arabinose (GoldBio), 35 μg/ml kanamycin (GoldBio), and 100 μg/ml carbenicillin (GoldBio).