Figure 9.

CaADC1 silencing compromises SA-dependent defense gene expression and SA accumulation in pepper leaves infected with Xcv. A, Expression profiles of defense-related genes. B, Free and total SA levels in empty vector control (TRV:00) and CaADC1-silenced (TRV:CaADC1) pepper leaves infected by Xcv. Total RNA was isolated from empty vector control (TRV:00) and CaADC1-silenced (TRV:CaADC1) pepper leaves inoculated with 5 × 10⁷ cfu mL⁻¹ of the Xcv strains Ds1 (EV) and Ds1 (avrBsT). Quantitative real-time PCR was performed for CaADC1 and pepper PR genes: CaPR1, CaPR10, and CaDEF1. Relative expression levels at 1 and 2 d after inoculation (dai) are shown. Relative expression values are normalized to the expression of pepper 18S ribosomal RNA in each sample. SA contents were determined in empty vector control and silenced leaves at 1 and 2 d after inoculation with Xcv. Data are means ± sd from three independent experiments. Asterisks indicate significant differences as determined by Student’s t test (P < 0.05). FW, Fresh weight.