Figure 4.

DNA Methylation Levels in Several Defense Genes.

(A) and (B) DNA methylation levels at CG sites (A) and CHG sites (B) of the NPR1 promoter region in elp2 and the wild type (WT).

(C) and (D) DNA methylation levels at CG sites in the coding region of NPR1 (C) and PAD4 (D) in elp2 and the wild type.

DNA samples were extracted from three biological replicates of each genotype. After bisulfite conversion and PCR amplification, the PCR products were cloned into pGEM-T easy vector. A total of 45 independent clones were sequenced for each genotype (15 for each DNA sample). The 15 clones from the same DNA sample were used to calculate methylation levels, which were then used for statistical analysis. Data represent the mean of three independent samples with sd. An asterisk indicates a significant difference between elp2 and the wild type (P < 0.05, t test).