Differential expression of genes representing the SA-signaling (A and B) or ET-signaling (C and D) pathways in petiole tissues of noninfested control or PA-infested A17 and ‘Jester’ plants, at 24, 36, or 72 h after aphid infestation. A, β-1,3-Glucanase (BGL). B, PR5. C, HEL. D, ACC. The relative transcript abundance of each gene was normalized to a tubulin gene and calculated using the formula 2^−ΔCT, where ΔC_T represents C_T of the gene of interest minus C_T of tubulin. Values are the mean and se of three biological replicates.