Fig. 3.

Effect of oxyR mutation on R. solanacearum virulence. Disease progression curves of R. solanacearum strains on wilt-tolerant tomato line Hawaii 7996 (A) and on wilt-susceptible tobacco cultivar Petit Havana SRI (B) following soil soak inoculation of unwounded plants, with bacterial cell suspensions of strain K60 (diamonds) and oxyR mutant K2690 (squares). Disease symptoms were evaluated daily for 14 days using a 0 to 4 disease index. (A) Inoculum was ∼5 × 10⁷ CFU/gram of soil. Results shown are the average of four independent experiments, with 16 plants per treatment per assay; bars indicate standard errors of the means. (B) Inoculum was ∼3 ×10⁷ CFU/gram of soil. Results shown are the average of two independent assays, with 10 plants per treatment per assay; bars represent standard errors of the means. An asterisk indicates a statistically significant difference according to Student's t test (P = 0.05).