Fig. 1: The SspBCDE defense system provides wide-ranging protection against coliphages in industrial E. coli strains.

a Plasmid pWHU3640 containing the sspBCDE module from E. coli 3234/A is schematically shown. b Expression of the SspBCDE defense system in E. coli MG1655 does not impair cell growth. Data are shown as the mean ± SD of three independent experiments. c The SspBCDE defense system provides protection against coliphages T1, JMPW2, T4, T5, T7, EEP, and lambda in E. coli MG1655. Bacteria were infected at t = 0 at multiplicities of infection (MOIs) of 5, 0.5 and 0.05. LB was used as a reference, and a final concentration of 100 µg/mL ampicillin was added to the medium to maintain the control empty vector and plasmid pWHU3640. Data are shown as the mean ± SD of three independent experiments. d Plaque morphologies of T1, JMPW2, T4, T7, EEP and lambda on E. coli MG1655 (pWHU3640) expressing SspBCDE. The red arrows indicate clear plaques of the phages, and the green arrows indicate turbid plaques of the phages. Experiments were repeated at least three times with similar results. e The SspBCDE defense system provides protection against coliphages in different E. coli hosts. Fold protection was determined by comparing the efficiency of plating (EOP) of phages on the pWHU3640-containing strain to the EOP on a strain that contains an empty vector. Data are shown as the mean ± SD of three independent experiments. * indicates that the coliphage did not infect this host. Source data are provided as a Source Data file.