Elucidation of metabolic responses in mud crab Scylla paramamosain challenged to WSSV infection by integration of metabolomics and transcriptomics.

White spot syndrome virus (WSSV) is a severe pathogen of mud crab Scylla paramamosain (S. paramamosain). Hemolymph, containing three types of hemocytes, is the key immunoregulatory tool of mud crab in response to pathogens. Herein, the metabonomics and transcriptomics analysis of hemocytes were adopted to investigate the immune response of S. paramamosain challenged to WSSV. We established the metabolic and transcriptional profiles of mud crab hemocytes with different treatments, including the control group (WT), WSSV early infected group (WSSV-6 h) and WSSV later infected group (WSSV-72 h). The results showed that 68 metabolites were dysregulated both in WSSV-infected mud crab of early stage and later stage, while 4452 genes were up-regulated and 9746 genes were down-regulated in WSSV-6 h, and 2016 genes were up-regulated and 6229 genes were down-regulated compared in WSSV-72 h. We found that several pathways were dysregulated at both metabolic and transcriptional levels, including ABC transporters, purine metabolism, taurine and hypotaurine metabolism in the WSSV early infected group, cysteine metabolism, methionine metabolism and biosynthesis of unsaturated fatty acids in the WSSV later infected group. In this context, through the integration of metabolomics and transcriptomics, our study provided a more comprehensive understanding of the biological process in mud crab against viral invasion.