Biofilm production and growth curves of the X. fastidiosa wild type and mutants. (A) Biofilm formation by the X. fastidiosa wild type and mutants 1A2, 5A7, and 6E11 following 7-day growth at 28°C. Biofilms were stained with 0.1% crystal violet. (B) The crystal violet stain was subsequently removed from the tubes with dimethyl sulfoxide and quantified for optical density at 620 nm. OD, optical density. (C) Growth curves for the X. fastidiosa wild type and mutants 1A2, 5A7, and 6E11 in PW medium at 28°C.