Developing CRISPR-Cas9 based genome-editing tools in entomopathogenic nematode Steinernema carpocapsae

Steinernema carpocapsae is parasitic to insects and mutualistic to bacterial symbionts Xenorhabdus nematophila, therefore is valuable to study naturally-occurring microbial symbiosis. As genetic tools in Xenorhabdus bacteria proved to be powerful to reveal the mechanisms underlying bacteria-host interactions, the lack of genetic tools on Steinernema nematodes hampered the study in the molecular pathways regulating the host side of the symbiotic conversation. Here we present our attempts to establish a CRISPR-Cas9 based approach to introduce mutations in S. carpocapsae genes predicted to encode collagens in the nematode cuticle. We are presenting our progress in genome-editing of S. carpocapsae and current efforts aiming to develop CRISPR-Cas9 co-conversion markers in S. carpocapsae by introducing mutations that cause distinctive and heritable phenotypes. Our CRISPR-Cas9 based tools will open a new revenue to study molecular pathways in host-microbes signaling particularly in naturally occurring parasitic and mutualistic symbiosis.