Meeting Abstract
Corals, which are the foundation of diverse coral reef ecosystems, are threatened by an increasing number of stressors, including disease. Still, knowledge of host response to disease is currently limited. This study employed novel network based approaches to better understand host immunity. Samples of the disease susceptible coral species Orbicella faveolata were exposed to immune challenge with bacterial LPS in a controlled laboratory setting. A combination of RNA sequencing and biochemical assays representing immune protein activity were used to characterize the holistic response of the corals to immune challenge. The data were analyzed using the R package, Weighted Gene Correlation Network Analysis (WGCNA), to build groups of coexpressed genes. These groups, as well as individual genes of interest, were then correlated to protein activity, measured by the biochemical assays, to identify genes which may contribute to phenotypic immune responses. Analysis revealed 371 differentially expressed genes following immune challenge, 77 of which were significantly correlated to one or more biochemical measures of immunity. Included in this group of 77 genes were members of each primary component of invertebrate immunity: receptors, signaling molecules, and effector molecules. Some of these differentially expressed genes with significant correlations to biochemical measures of immunity displayed dysfunctional patterns of expression during immune challenge. Genes such as green fluorescent protein, which has antioxidant properties and likely contributes to host immune response, decreased in expression following immune challenge. These counter-intuitive patterns of gene expression may help in part explain the well documented vulnerability of O. faveolata to disease.
