Inactivation of Conserved C. elegans Genes Engages Pathogen- and Xenobiotic-Associated Defenses

The nematode C. elegans is attracted to nutritious bacteria and is repelled by pathogens and toxins. Here we show that RNAi and toxin-mediated disruption of core cellular activities, including translation, respiration, and protein turnover, stimulate behavioral avoidance of normally attractive bacteria. RNAi of these and other essential processes induces expression of detoxification and innate immune effectors, even in the absence of toxins or pathogens. Disruption of core processes in non-neuronal tissues was sufficient to stimulate aversion behavior, revealing a neuroendocrine axis of control that additionally required serotonergic and Jnk kinase signaling pathways. We propose that surveillance pathways overseeing core cellular activities allow animals to detect invading pathogens that deploy toxins and virulence factors to undermine vital host functions. Variation in cellular surveillance and endocrine pathways controlling behavior, detoxification, and immunity selected by past toxin or microbial interactions could underlie aberrant responses to foods, medicines, and microbes. [Display omitted] ► Inactivation of vital cellular processes by RNAi stimulates microbial aversion ► Drugs and toxins targeting the vital cell processes stimulate aversion behavior ► Immunity and detoxification defenses are induced by RNAi against cellular processes ► Jnk kinase and serotonergic signaling mediate the aversion response Invading pathogens often co-opt or disrupt core cellular pathways such as translation and respiration. RNAi of these pathways in worms induces detoxification and innate response genes and triggers a neuroendocrine axis that stimulates avoidance of harmful microbes, suggesting the existence of mechanisms that survey the status of critical cellular pathways to alert the organism of the presence of pathogens.