Table 1.
Virulence of Clavibacter michiganensis ssp. michiganensis strains on tomato plants.
| CFU/g in planta ¶ | ||||||
|---|---|---|---|---|---|---|
| Strain | HR * | AUDPC † | Disease incidence ‡ | Petiole lesion length (cm) § | 9 DPI | 21 DPI |
| Cmm0317 | + | 139 (±36) B | 15/15 | 0 | 2.78 × 108 B | 5.36 × 108 C |
| ΔCmEXLX2 | + | 430 (±64) A | 15/15 | 2.16 (±0.70) | 3.72 × 109 A | 4.82 × 109 A |
| CΔCmEXLX2+ | + | 157 (±21) B | 15/15 | 0.59 (±0.21) | 2.25 × 108 B | 2.30 × 109 B |
| Water control | – | 0.0 | 0/15 | 0 | 0.0 | 0.0 |
*Induction of a hypersensitive response (HR) in Mirabilis jalapa: +, positive for HR reaction; –, negative for HR reaction.
†The mean area under the disease progress curve (AUDPC) for disease severity for three independent experiments is given. Differences among strains were determined with PROC GLIMMIX (P < 0.05) followed by Tukey–Kramer post‐test (P < 0.05). AUDPC values followed by the same letters are not significantly different. Numbers in parentheses indicate the standard error associated with the AUDPC values.
‡Expressed as the number of wilting plants/number of inoculated plants characterized at 21 days post‐inoculation (DPI).
§The mean length of lesions located on the inoculated petiole at 21 DPI. Numbers in parentheses indicate the standard error associated with the lesion lengths.
¶The mean in planta population [colony‐forming units (CFU)/g] recovered from a 0.5‐cm section of tomato stem tissue located 1 cm above the inoculation site at both 9 and 21 DPI. Significant differences amongst strains were tested by PROC GLIMMIX (P < 0.05) followed by Tukey–Kramer post‐test (P < 0.05). In planta populations followed by the same letters are not different.