Meeting Abstract
7.2 Friday, Jan. 4 Identification of symbiotic-specific genes reveals a role for host immunity in a cnidarian-dinoflagellate mutualism MOUCHKA, M E*; LEHNERT, E M; BURRIESCI, M S; SCHWARZ, J; PRINGLE, J R ; Cornell University; Stanford University ; Stanford University ; Vassar College; Stanford University mep74@cornell.edu
Many cnidarians harbor intracellular photosynthetic dinoflagellates in a mutualistic relationship. While some facets of this mutualism have been relatively well studied, we know very little about the cellular and molecular mechanisms that underlie the establishment and maintenance of cnidarian-dinoflagellate symbioses. The stability of this relationship presumably involves a complex interplay between the symbiont and the host immune system. To gain a better understanding of the role of host immunity in mutualistic interactions, we used RNA-Seq to characterize differential gene expression between symbiotic and aposymbiotic anemones. Data from two distinct RNA-Seq experiments were combined to identify a robust set of 1,163 differentially expressed genes. 812 genes were up-regulated in symbiotic anemones, while 351 were down-regulated, with the majority of these genes having functions in metabolism and transport. A subset of differentially expressed genes function in immune-related processes, including inflammation, wound healing, regulation of the JNK cascade, complement activation, and apoptosis. Genes of interest from these categories (based on log2 fold expression) include scavenger receptor B1 (infinitely up-regulated), TNF receptor superfamily member 27 (5.9), and mannan-binding lectin serine peptidase 1 (-1.6). Our results suggest a role for the host immune system in the maintenance of the symbiotic relationship. In addition, we have generated a list of candidate genes whose function in the onset, regulation, and breakdown of the symbiotic state can be investigated in further detail. Our results offer new insights into genes that play a role in symbiotic homeostasis and will leverage a better understanding of cnidarian-dinoflagellate interactions.
