TABLE 3.
Virulence of B. cepacia K56-2 mutants in the alfalfa model
| Strain | Gene mutated | % Seedlings with symptomsa | No. of CFU (107) recovered/seedlingb | Reference |
|---|---|---|---|---|
| K56-2 (wild type) | 100 | 16 ± 6.4c | 19 | |
| K56pvdA::tp | Ornibactin biosynthesis | 30 ± 5d | 1.5 | 33 |
| K56orbA::tp | Ornibactin receptor | 98 ± 3 | 8.3 | 32 |
| K56-2-9 | Zinc metalloprotease | 100 | 6.5 | 8a |
| K56-H15 | Tn5-OT182 insertion | 3 ± 6d | 0.29 ± 0.2c,e | Unpublished data |
a
Values are means ± standard deviations of three assays (20 seedlings/assay). The starting inoculum was between 1 × 105 and 3 × 105 CFU. Any seedlings with visible symptoms including yellow leaves, stunted root, and brown necrotic regions were considered positive for symptoms of disease.
b
Values are means of one assay (two seedlings/assay) unless noted otherwise.
c
Values are means ± standard deviations of two assays (two seedlings/assay).
d
Significantly different from the value for K56-2 (P < 0.001 by ANOVA).
e
Significantly different from the value for K56-2 (P < 0.05 by ANOVA).