Transcriptome and expression profiling analysis revealed changes of multiple signaling pathways involved in immunity in mud crab Scylla paramamosain during Vibrio parahaemolyticus infection
Purpose:The mud crab Scylla paramamosain is an economically important marine crab in China suffering from severe outbreaks of infectious disease caused by marine bacteria such as Vibrio Parahaemolyticus, resulting in great economic losses. However, the mechanisms involved in the immune response of this crab to bacterial infection are not fully understood. To understand the molecular mechanisms underlying the immune response to such pathogenic bacteria, we used high-throughput deep sequencing technology to investigate the transcriptome and comparative expression profiles of the mud crab S.paramamosain infected with V.parahaemolyticus. Methods: The hemocytes sampled at 0-24h after infection with V.parahaemolyticus were used for transcriptome analysis. The hemocytes sampled at 24 h after injections with V.parahaemolyticus and no injected 0h(as control) were used for gene expression profiling analysis. Results: A total of 52,934,042 reads were obtained and assembled into 186,193 contigs in transcriptional responses of the V.parahaemolyticus-infected mud crab. Via annotation to the NCBI database and the Swissprot database, we obtained 48,934 identified unigenes. In total, 10,139(20.7%) unigenes were classified into Gene Ontology, and 25,349 unigenes were found in 20 KEGG categories. These genes included representatives from almost all functional categories. By using Solexa/Illumina''s DeepSAGE, 1213 differentially expressed genes (P value < 0.05) were detected in comparative analysis of the expression profiles between V.parahaemolyticus-infected crabs and control crabs, including 538 remarkably upregulated genes and 675 remarkably downregulated genes. Conclusions: Based on our results, we conclude that the inflammatory response may play an important role in the early stages of infection. The signaling cascades such as the chemokine, JAK-STAT, and MAPK pathways are regulated by V.parahaemolyticus infection. These results revealed changes of multiple signaling pathways involved in immunity during V.parahaemolyticus infection, which will facilitate our comprehensive understanding of the mechanisms involved in the immune response to bacterial infection in the mud crab. Overall design: Transcriptome: hemocytes mRNA profiles of 0-24h Mixture (Mix). Gene expression profiling: 24 h after injections (24hVP) and no injected 0h (as control) (0hDZ) were generated by deep sequencing, in triplicate, using Illumina HiSeq 2000.