Reported transgenerational responses to Pseudomonas aeruginosa in Caenorhabditis elegans are not robust

We report our attempt to replicate reports of transgenerational epigenetic inheritance in Caenorhabditis elegans . Multiple laboratories report that C. elegans adults and their F1 embryos exposed to the pathogen Pseudomonas aeruginosa show pathogen aversion behavior and increased daf-7/TGFβ reporter gene expression. However, results from one group show persistence of both through the F4 generation. We failed to consistently detect either the avoidance response or elevated daf-7 expression beyond the F1 generation. We confirmed that the dsRNA transport proteins SID-1 and SID-2 are required for intergenerational (F1) inheritance of pathogen avoidance, but not for the F1 inheritance of elevated daf-7 expression. Reanalysis of RNA seq data provides additional evidence that this intergenerational inherited PA14 response may be mediated by small RNAs. The experimental methods are well-described, the source materials are readily available, including samples from the reporting laboratory, and we explored a variety of environmental conditions likely to account for lab-to-lab variability. None of these adjustments altered our results. We conclude that this example of transgenerational inheritance lacks robustness, confirm that the intergenerational avoidance response, but not the elevated daf-7p::gfp expression in F1 progeny, requires sid-1 and sid-2 , and identify candidate siRNAs and target genes that may mediate this intergenerational response.