TABLE 2.
Comparison of disease severities with Erwinia amylovora strain Ea1189, ppGpp mutants, and complementation strains
| Strain | No. of shoots infected/no. of shoots inoculated | Length of necrosis (cm) (mean ± SD)a |
|---|---|---|
| Ea1189 | 7/7 | 30.2 ± 5.6a |
| ΔrelA mutant | 2/7 | 10 ± 2.8c |
| ΔrelA(pRelA) mutant | 7/7 | 30.8 ± 3.2a |
| ΔspoT mutant | 6/7 | 19 ± 1.6b |
| ΔspoT(pSpoT) mutant | 6/7 | 29 ± 3.1a |
| ΔdksA mutant | 0/7 | —NI |
| ΔdksA(pDksA) mutant | 7/7 | 32.2 ± 5.08a |
| ΔrelA/spoT mutant | 0/7 | —NI |
| ΔrelA/spoT(pSpoT) mutant | 3/7 | 1.16 ± 0.28d |
| ΔrelA/dksA mutant | 0/7 | —NI |
| ΔrelA/dksA(pRelA) mutant | 0/7 | —NI |
| ΔrelA/dksA(pDksA) mutant | 2/8 | 3.25 ± 1.06c,d |
a
Average necrosis length for 7 or 8 inoculated apple shoots (cv. ‘Gala’) at 7 days postinoculation. —, no disease detected. The experiment was repeated with similar results. One-way ANOVA and Student's t test (P = 0.05) were used to analyze the data. Values marked with the same letter were not significantly different (P < 0.05). NI, not included in statistical analysis.