Fig 2.

Growth and competition in laboratory medium and soil. (A) Growth curves of Pf0-1 and Pf0-gacA⁺ in rich medium (solid line) and a defined minimal medium (dashed line). (B) Pf0-1 and Pf0-gacA⁺ were inoculated into soil, and viable bacteria were monitored over a 30-day period. Data points represent individual soil columns, and horizontal lines represent median values. Differences between the parent and the Gac⁺ derivative are not statistically significant (P > 0.05 for all time points), as calculated with the Mann-Whitney nonparametric statistical hypothesis test. For competition assays (C), a 1:1 ratio of each strain was used to inoculate a single soil column. Cell numbers for each strain were assessed over a 30-day period, and average CFU counts are plotted. In all three panels, Pf0-1 and Pf0-gacA⁺ data points are represented as closed and open circles, respectively.