Chemosensory Neurons Modulate the Response to Oomycete Recognition in Caenorhabditis elegans

Understanding how animals detect and respond to pathogen threats is central to dissecting mechanisms of host immunity. The oomycetes represent a diverse eukaryotic group infecting various hosts from nematodes to humans. We have previously shown that Caenorhabditis elegans mounts a defense response consisting of the induction of chitinase-like (chil) genes in the epidermis to combat infection by its natural oomycete pathogen Myzocytiopsis humicola. We provide here evidence that C. elegans can sense the oomycete by detecting an innocuous extract derived from animals infected with M. humicola. The oomycete recognition response (ORR) leads to changes in the cuticle and reduction in pathogen attachment, thereby increasing animal survival. We also show that TAX-2/TAX-4 function in chemosensory neurons is required for the induction of chil-27 in the epidermis in response to extract exposure. Our findings highlight that neuron-to-epidermis communication may shape responses to oomycete recognition in animal hosts. [Display omitted] •C. elegans senses its natural oomycete pathogen M. humicola without infection•Exposure to a pathogen extract triggers an oomycete recognition response•Upon pathogen detection, C. elegans resists infection through changes in the cuticle•The response involves signaling between sensory neurons and the epidermis The oomycetes include key eukaryotic pathogens of animals and plants, but animal-oomycete interactions are little explored. Fasseas et al. report that C. elegans has evolved appropriate means to sense its natural oomycete pathogen Myzocytiopsis humicola and mount anticipatory defense response in the epidermis to protect from an upcoming infection threat.