FIG 1.

Identification of B. bacteriovorus mutants with altered fitness in bacterial predation. (A) We generated a complex B. bacteriovorus transposon mutant library and subjected it to transposon insertion sequencing (Tn-seq) before and after expansion on V. cholerae and E. coli. Mutants with decreased fitness (W < 0.1) are shown and categorized according to gene ontology terms. (B) A correlation plot of fitness values for B. bacteriovorus preying on planktonic V. cholerae (VCPL) or E. coli (ECPL) in the full Tn-seq. Each dot represents the fitness values for one gene against the two-prey species on the x and y axes. (C) Diagram of the B. bacteriovorus predatory life cycle. Mutants can show defects in prey attachment (class I), killing (class II), rounding (class III), or exit from prey (class IV). (D) Correlation plots of fitness values comparing results from the full- and mini-Tn-seq screens. (E) E. coli survival following infection with B. bacteriovorus mutants or complemented strains. The average E. coli survival percentage and standard errors of the mean (SEM) for three biological replicates are shown. Significance was determined by comparing E. coli survival against each strain compared to the uninfected (Uninf) control. *, P < 0.001 (ANOVA and Dunnett’s multiple-comparison test).