Growth and persistence in Nevada arid soil of P. fluorescens Pf0-1 carrying mutations in arid soil-induced genes relative to wild-type Pf0-1 and Pf0-1Δ dapB . A. When inoculated at relatively high density, the sif2 (Pfl01_2143) mutant fails to maintain the population density reached by wild-type Pf0-1 while the sif10 (Pfl01_5595) mutant shows no aberrant phenotype. B. When inoculated at relatively lower density, the sif10 (Pfl01_5595) mutant fails to establish the same population level as wild-type Pf0-1, whereas the sif2 (Pfl01_2143) mutant is indistinguishable from wild-type. In both panels, error bars represent 4 replications. Error bars represent standard errors. Anova for these experiments indicates significant values at P ≤0.01. For the experiments in 1A, difference values between any two means that were greater than 0.11 (day1), 0.05 (day3) and 0.08 (day7) denoted statistical significance. For the experiments in 1B, difference values between any two means that were greater than 0.07 (day1), 0.07 (day3) and 0.11 (day7) denoted statistical significance.