Comparison of gene induction over time after P. rapae feeding in cultivars Rivera and Christmas Drumhead. A, Venn diagram representing the distribution in Rivera of transcripts activated after 48 and 72 h of P. rapae challenge. B, Venn diagram representing the distribution in Christmas Drumhead of transcripts activated after 24, 48, and 72 h of P. rapae challenge. The numbers in the overlapping area indicate the shared number of genes in the comparisons and include genes with an average expression ratio ≥ 2-fold and a P value < 0.05 in both experiments. Numbers outside the overlapping area represent genes specifically induced at one time point.