The Caenorhabditis elegans p38 MAPK Gene plays a key role in protection from mycobacteria

Mitogen‐activated protein kinases (MAPK) are critical mediators of cellular responses to pathogens and are activated in response to infection, but investigation is difficult in multi‐cell hosts due to developmental lethality of mutations. Mycobacterium marinum (Mm) is an established model for tuberculosis, a disease afflicting nearly one‐third of the world's population. We found that Mm‐infected Caenorhabditis elegans display >80% mortality, but nonpathogenic M. smegmatis cause <15% mortality. C. elegans display pathological changes when infected with Mm, whereas Mm mutants produce lower mortality, suggesting that C. elegans is a promising virulence model for detailed genetic analysis. C. elegans MAPK mutants are hypersusceptible to mycobacterial infection; however, the C. elegans TOL‐like, TGF‐β and insulin‐like pathway genes do not play important roles in susceptibility. We show that pathogenic mycobacteria inhibit MAPK‐mediated protection through the MAPK phosphatase gene and demonstrate that C. elegans provide a genetically tractable pathogenicity model of both the host and pathogen.