Novel infection by kills hosts through intestinal perforation.

The nematode has emerged as a popular model system to investigate cell biology and host-pathogen interactions. Presently, is studied as a natural host of intracellular pathogens such as microsporidia and Orsay virus along with extracellular bacterial and fungal pathogens. The use of as a model in host-pathogen research is limited by the number of naturally occurring pathogens to the organism. Through a sampling project to identify new pathogens of , we identified the fungus as a pathogen of species. We observed the fungus in the intestinal lumen of wild-caught , and co-culturing the wild-caught species with infection reporter confirmed infection by . This study characterizes the fungal infection by in nematodes. Fluorescence microscopy with fungal staining revealed the life cycle of within multiple species at varying growth stages. We observed the killing of nematodes by via intestinal perforation and assessed its' host range through a series of lifespan assays. We investigated the food preference of and determined that nematodes show a preference towards food that contains spores. Lastly, we evaluated common transcriptional immune responses and found that does not induce genes associated with the intracellular pathogen response or other responses seen with previously studied bacterial and fungal pathogens. Characterization of this fungal infection in nematodes will provide new insights into the biology of pathogenic fungi and host immune responses.