Fig 1. Transposon-sequencing identifies sweD and sweC as synthetic lethal with lytE.

(A) Transposon insertion profiles from wild-type (WT) and ΔlytE libraries. Three regions of the genome are shown. The height of each line reflects the number of sequencing reads at this genomic position. Transposon insertions in cwlO, ftsE, ftsX, sweD (yqzD) and sweC (yqzC) are underrepresented in the ΔlytE library compared to WT. No insertions were mapped to the essential gene trxB in either library. (B) sweD and sweC mutants are synthetically lethal with ΔlytE. Spot dilutions of the indicated strains in the presence and absence of inducer. All strains were grown in the presence of IPTG (500 μM) to OD₆₀₀ ~2.0. The cultures were washed twice without inducer, resuspended at an OD₆₀₀ of 1.5, and 10-fold serially diluted. Five microliters of each dilution was spotted onto LB agar plates with and without IPTG. Representative plates from one of three biological replicates are shown. (C) Schematic representations of SweD and SweC. Transmembrane segments (TM); putative coiled-coil (CC); helix-turn-helix motif (HTH); and LysM homology domain are indicated.