Growth and fitness of N. attenuata plants impaired in herbivory-induced defense signaling. (A) Mean (± SE, n ≥ 9) stalk length of irSIPK and irWIPK plants grown for 44 days in the plant’s natural habitat (Utah, USA) compared to size-matched wild type (WT) plants. (B) Mean (± SE) dry mass (n ≥ 3, pooled samples, each containing 5 biological replicates) and total capsule number (n ≥ 19) of transgenic plants (irSIPK, irWIPK) grown in competition with wild type (WT) plants. To simulate herbivory, three rosette leaves of each plant were wounded with a pattern wheel (W) and treated with 10 μL 1:5 diluted Manduca sexta oral secretions (OS). Untreated plants served as controls. (C) Mean (± SE, n ≥ 16.) relative root growth difference to WT in wounded seedlings grown in competition (asteriks indicate significant differences between irLOX3 and irWIPK when compared to irSIPK plants (ANCOVA, F2,344 = 13.46, p < 0.001)) and mean (± SE, n = 8) seedling fresh mass grown under low nutrient conditions. Asteriks indicate significant differences between a transgenic line and WT in one pot (Welch two sample T-test; ***: p < 0.001; **: p < 0.01; *: p < 0.05).