(A) Adult pathogen training protocol. Choice Index = (# of worms on OP50 - # of worms on PA14)/(Total # of worms). (B) 4h of training on PA14 is sufficient to elicit maternal avoidance (P0) of PA14, but is not sufficient for progeny avoidance (F1). At least 3 biological replicates were performed. (C) 24h of training on PA14 induces both pathogen avoidance and transgenerational inheritance of pathogen avoidance (F1); n = 177 replicate assays. (D) 24h of training on avirulent Pseudomonas (LasR) does not induce maternal pathogenic learning or progeny avoidance of PA14. At least 3 biological replicates were performed. (E) L1-imprinted animals (24h) exhibit adult (Day 1) aversion to PA14, but progeny of imprinted mothers do not. At least 3 biological replicates were performed. (F) CREB (crh-1) is not required for maternal pathogenic learning or progeny avoidance of PA14. At least 3 biological replicates were performed. (G) 24h of training on S. marcescens (red) is sufficient to elicit maternal avoidance of S. marcescens. However, 24h of training on PA14 (blue) does not induce maternal avoidance of S. marcescens. 2 biological replicates were performed. (H) PA14 training (blue) induces maternal avoidance of PA14, while S. marcescens (red) training does not induce avoidance of PA14. 24h (I) or 40h (J) of training on S. marcescens is sufficient to elicit maternal (P0) avoidance of S. marcescens, but does not induce progeny avoidance (F1). At least 3 biological replicates were performed. (K) Progeny of (b) PA14-trained mated parents (PA14-trained males x PA14-trained females) inherit pathogen avoidance, while progeny of (a) OP50-trained mated parents (OP50-trained males x OP50-trained females) prefer PA14. Progeny in which only one parent was trained on PA14 ((c) PA14-trained male x OP50-trianed female, or (d) OP50-trained male x PA14-trained female) inherit pathogen avoidance. One-Way ANOVA, Tukey’s multiple comparison test, mean ± SEM. n ≥ 7 choice assay plates containing 50-200 worms. *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001, ****p < 0.0001, ns = not significant.