Fig 6.
(A) Virulence assay in sweet corn seedlings. Fourteen-day-old sweet corn seedlings were inoculated with either the wild-type P. stewartii (DC283), the crtB∷Mar2xT7 (crtB) mutant, the crtB∷Mar2xT7/pMOJ14 (crtB/crtB+) complemented strain, or 1× PBS-Tween 20 buffer. Seedlings were stab inoculated below the secondary leaf with 5 μl of inoculum prepared in 1× PBS-Tween 20 buffer and adjusted to an OD600 of 1.0. Disease ratings were assessed at 10 days postinoculation. The crtB∷Mar2xT7 (crtB) mutant is significantly comprised in virulence compared to the WT (DC283) strain. Virulence was fully restored in the crtB∷Mar2xT7/pMOJ14 (crtB/crtB+) complemented strain. Plants inoculated with 1× PBS-Tween 20 buffer alone did not develop any Stewart's wilt symptoms. (B) Total fresh weight (g) of sweet corn seedlings. Plants were weighed 12 days post-inoculation. The results represent the means ± SE for 12 replicates from three independent experiments.