Transcriptomic analysis of exosomal shuttle mRNA in Pacific oyster Crassostrea gigas during bacterial stimulation

As marine invertebrates, oysters lack adaptive immunity and employ innate immunity as the front line and almost the solo defense mechanism to protect them against invaders. Accumulating research achievements demonstrated that exosomes could act as innate immune effectors that contribute to host defense mechanism. To better understand the immune functions of exosomes in Crassostrea gigas against bacterial stimulation, RNA-Seq was applied to explore the global expression changes of exosomes in oyster after Staphylococcus aureus and Vibrio splendidus stimulation. Totally 171573691 single end raw reads were yielded via Ion Torrent Proton sequencing, which were trimmed into 121988325 clean reads, and then 1505 abundant exosomal shuttle mRNAs (esmRNAs) were identified. Gene ontology (GO) analysis revealed that these abundant esmRNAs could be categorized into 15 cellular components, 12 molecular functions and 21 biological processes, and these abundant esmRNAs were mapped onto 62 biological signaling pathways by KEGG. In total, 68 significant differentially expressed genes (DEGs, Fold change ≥ 2, Q-value