Transcriptome analysis of Manila clam (Ruditapes philippinarum) under Vibrio parahaemolyticus challenge in a low-salinity environment provides molecular insights into immune response

Bacterial infections caused high mortality of Manila clam (Ruditapes philippinarum) after the sudden drop in salinity of seawater, which caused serious economic losses. Therefore, we explored the molecular mechanism of V. parahaemolyticus-mediated immunity of R. philippinarum under low-salinity condition. In this study, Manila clams treated with low-salinity (CD), V. parahaemolyticus-treated under low-salinity condition (HCD), and a blank group (CC) were sequenced through the Illumina HiSeq platform, and we verified 15 immune-related DEGs (12 up-regulated genes and 3 down-regulated genes) through quantitative real-time PCR (qRT-PCR), the results were consistent with those detected from the transcriptome. In addition, the results of KEGG pathway enrichment analysis showed that the different expression genes (DEGs) were mostly enriched in the lysosome and phagosome pathway exhibited upregulated expression throughout the V. parahaemolyticus infection. Among them, lysosome and phagosome-related genes were induced after R. philippinarum treated with V. parahaemolyticus. Thus, our results proved that the important role of regulatory mechanism of immune homeostasis mediated by the lysosome and phagosome pathway in R. philippinarum against V. parahaemolyticus infection. Altogether, this work provides a new information about the immune regulatory mechanisms of Manila clam response to V. parahaemolyticus challenge in a low-salinity environment.