Figure 8.

CaRING1-OX transgenic Arabidopsis plants exhibit enhanced resistance to Pst DC3000 infection. A, RT-PCR analysis of CaRING1 expression in wild-type (WT) and 35S:CaRING1 transgenic lines. Expression of the ubiquitin (UBQ) gene was used as a control. B, Disease symptoms on the leaves of wild-type or transgenic plants 6 d after infection with Pst DC3000 (10⁶ cfu mL⁻¹). C, Bacterial growth in wild-type and transgenic plant leaves at 0 or 3 d after inoculation with Pst DC3000 (10⁵ cfu mL⁻¹). Data represent means ± sd from three independent experiments. Statistically significant differences between means were determined using Fisher’s lsd test (P < 0.05). D, Expression of CaRING1, AtPR1, AtPDF1.2, and AtRD29a in wild-type and transgenic plants (T3) at 24 and 48 h after infiltration with Pst DC3000. Quantitative analysis was performed using RT-PCR, and relative gene expression levels were normalized using the constitutively expressed gene AtACT1. Data represent means ± sd from three independent experiments. Asterisks indicate significant differences between empty vector control and CaRING1-silenced pepper plants as determined by Student’s t test (P < 0.05). E, Free SA and SAG levels in wild-type and transgenic plants 24 and 48 h after infiltration with Pst DC3000. Data represent means ± sd from two independent experiments. Asterisks indicate significant differences between wild-type and transgenic plants as determined by Student’s t test (P < 0.05). FW, Fresh weight. [See online article for color version of this figure.]