Abstract

The interaction and communication between bacteria and their hosts modulate many aspects of animal physiology and behavior. Dauer entry as a response to chronic exposure to pathogenic bacteria in Caenorhabditis elegans is an example of a dramatic behavioral decision to survive. This response depends on the RNAi machinery suggesting the involvement of sRNAs as effectors. Interestingly, dauer formation occurs after two generations of interaction with moderate pathogenic bacteria of different species. Therefore, we sought to discover the identity of C. elegans RNAs involved in pathogenesis-induced diapause. Using transcriptomics and differential expression analysis of coding and non-coding long and small RNAs, we found that mir-243-3p is the only transcript upregulated in both animals exposed to either P. aeruginosa or S. enterica for two generations. Phenotypical analysis of mutants showed that mir-243 is required for dauer formation under pathogenesis but not under starvation. Moreover, DAF-16, a master regulator of key defensive processes in the animal and required for dauer formation was found to be necessary for mir-243 expression. This work highlights the role of a small non-coding RNA in the intergenerational defensive processes against pathogenic bacteria and inter-kingdom communication.