The p38 MAPK/PMK-1 Pathway Is Required for Resistance to Nocardia farcinica Infection in Caenorhabditis elegance .

is an opportunistic pathogen that causes nocardiosis primarily in patients with compromised immune systems. In this study, we used the genetically tractable organism as a model to study the innate immune responses to infection. We found that unlike other pathogenic bacteria such as and , failed to kill adult worms. In another words, adult worms exposed to exhibited a normal lifespan, compared with those fed the standard laboratory food bacterium OP50. Interestingly, deletion of three core genes (, and ) in the p38 MAPK/PMK-1 pathway reduced the survival of worm exposure to , highlighting a crucial role of this pathway for in resistance to . Furthermore, our results revealed that exposure up-regulated the level of PMK-1 phosphorylation. The activation of PMK-1 promoted nuclear translocation of a transcription factor SKN-1/Nrf2, which in turn mediated infection resistance in . Our results provide an excellent example that the integrity of immune system is key aspect for counteract with pathogenesis of .