FIG 5.
Competition assays to validate genes important for desiccation tolerance. (A and B) Stationary phase cultures of WT cells and individual transposon insertion mutants (marked with a gentamicin resistance cassette) were suspended in PBS, mixed 1:1 (108 cells of each strain), desiccated on plastic, and incubated at room temperature. The next day, cells were recovered and plated on LB and LB plates containing gentamicin to determine a competitive index. The competitive indices for 15 of the cluster I genes (A) with roles in nutritional stress and/or desiccation tolerance and 22 of the cluster II genes (B) important for desiccation tolerance. An arbitrary number was assigned for carB and surA to calculate CI, as no viable cells were recovered for these 2 mutants. Data represent the average of at least 3 replicates. Mutants with significant reductions in the CI are indicated with an asterisk (P < 0.05).