Figure 6.

1,4‐DPCA treatment mimics the active infection tolerance in the host. A) In groups that received prophylactic treatment, only those in which the pathogens are pretreated (P+) survive at similar rates to controls at 24 h postinfection. Embryos treated with prophylactic 1,4‐DPCA (U ‐P/+E) exhibit greater survival than untreated infection (U ‐P/‐E), but lower survival than uninfected controls. Pathogen load decreases with prophylactic treatment of pathogens (**p = 0.002), but the load remains higher than that for uninfected controls. The HPRI score is higher for all treatment conditions than untreated infection, including the prophylactic treatment of embryos (*p = 0.02), but remains lower than the uninfected controls (***p < 0.001; ****p < 0.0001; each data point represents n = 10 embryos). Statistical analysis was performed using separate one‐way ANOVAs for each metric, with Šídák's multiple comparison test comparing the uninfected controls and untreated infection to each treatment group. B) For groups treated with 1,4‐DPCA after the onset of infection (T), survival rates do not differ from uninfected controls at 24 h postinfection. Pathogen load decreases in all postinfection treatment groups relative to untreated infection, however, the prophylactically treated and postinfection treated embryos maintain pathogen burdens higher than the uninfected controls. The HPRI score is higher for all treatment conditions than untreated infection, but remains lower than the uninfected controls (**p = 0.002; ***p < 0.001; ****p < 0.0001; each data point represents n = 10 embryos). Statistical analysis was performed using separate one‐way ANOVAs for each metric, with Šídák's multiple comparison test comparing the uninfected controls and untreated infection to each treatment group. C) Heatmap comparing the expression of 42 genes that undergo significant changes in gene expression relative to uninfected controls at 24 h postinfection (p _adj < 0.001). The prophylactically and postinfection treated group (T +P/+E) clusters with the uninfected control group. Prophylactic treatment of pathogens (+P) and the post‐treatment (T) paradigms produce host responses that closely cluster. Embryo prophylaxis alone (U ‐P/+E) produces a host response that is similar to lack of treatment (U ‐P/‐E). D) Differentially expressed genes are involved in GO pathways related to metal ion binding, hydrolase activity, RNA polymerase binding, and transcription factor activities.