Bathymodiolus platifrons Raw sequence reads

Bathymodiolin mussels adapted the chemosynthetic ecosystem, such as cold seep and hydrothermal vent, by harboring intracellular symbiont in gill. However, despite the research efforts, the molecular mechanism governing host-symbiont interaction in deep-sea mussels are still largely unknown. Here, using the model deep-sea mussel Bathymodiolus platiforns, we profiled the transcriptomic dynamic of the mussel gill during the loss and reacquisition of symbiont with RNA-seq technology. The analysis of DEGs (Differentially Expressed Genes) between untreated and symbiont loss samples revealed that the gill went through metabolic and cellular organizational changes mainly by promoting ribosomal activities and activating ubiquitin-proteasome system and autophagy. Meanwhile, the DE immune genes suggested that the host recognizes and interacts with endosymbiont through the pattern recognizing receptors, especially the Toll-like receptors. In addition, the DEGs between symbiont treated and environmental bacteria treated samples shed light on the mechanism of symbiont recognition and acquisition. The symbiont treatment not only partially reversed the transcriptomic changes caused by symbiont loss, but also suppressed host immune system which might facilitate the symbiont's entrance and survival in the host bacteriocytes. All together, these results suggested that the host-symbiont system in B. platifrons is tightly regulated but also with plasticity to fit environmental fluctuations.