FIG 3.

Nitrate assimilation is required for full R. solanacearum virulence on tomato. (A) Disease caused by wild-type strain UW551 (●) or assimilatory nitrate reductase mutant nasA (□) following naturalistic soil soak inoculations of susceptible tomato plants (cv. Bonny Best), as illustrated in Fig. 5A. The data shown reflect mean daily ratings on a disease index scale of 0 to 4 of three biological replicates, each containing 8 to 16 plants/treatment for a total n = 28 plants. P = 0.002 (two-way repeated-measures ANOVA). (B) Percentage of plants showing any wilt symptoms each day for the experiment described above. Black bars, wild-type strain UW551; white bars, nasA mutant. Bars indicate the standard errors of the mean; asterisks indicate days when percent symptomatic plants were significantly different between wild-type and nasA treatments (P < 0.05 [unpaired t test]).