Transcriptomic, Functional, and Network Analyses Reveal Novel Genes Involved in the Interaction Between and .

The bacterivorous nematode is an excellent model for the study of innate immune responses to a variety of bacterial pathogens, including the emerging nosocomial bacterial pathogen . The study of this interaction has ecological and medical relevance as is found in association with and other nematodes in the wild and is an emerging opportunistic bacterial pathogen. We identified 393 genes that were differentially expressed when exposed to virulent and avirulent strains of and an avirulent strain of . We then used a probabilistic functional gene network model (WormNet) to determine that 118 of the 393 differentially expressed genes formed an interacting network and identified a set of highly connected genes with eight or more predicted interactions. We hypothesized that these highly connected genes might play an important role in the defense against and found that mutations of six of seven highly connected genes have a significant effect on nematode survival in response to these bacteria. Of these genes, C48B4.1, , and are needed for combating the virulent JCMS strain, while was solely involved in response to the avirulent K279a strain. We further found that and were up regulated in response to JCMS vs. K279a, while C48B4.1, , and were down regulated. Only had a documented role in innate immunity, which demonstrates the merit of our approach in the identification of novel genes that are involved in combating infection.