Transcriptome profiling of the Eriocheir sinensis thoracic ganglion under the Spiroplasma eriocheiris challenge

Spiroplasma eriocheiris, has been identified as a novel lethal pathogen of Eriocheir sinensis tremor disease (TD, typically paroxysmal tremors of the pereiopod). The thoracic ganglion of E. sinensis infected by S. eriocheiris was the direct reason of the TD. This study was designed to understand of TD processes in crab and the immune response of thoracic ganglion at the transcriptomic levels. The transcriptomic profiles of thoracic ganglion in the experimental group (S. eriocheiris inject, termed SI) and the control group (R2 medium inject, termed RI) were obtained using Illumina HiSeq 2500. In total, there were 60,159,089 and 47,613,445 high-quality clean reads assembled from SI and RI, respectively. In addition, 39,636 unigenes were obtained with an N50 length of 575 bp. Moreover, by RPKM analysis, a total of 8049 differentially expressed genes (SI vs RI) were detected, including 927 up-regulated and 7122 down-regulated genes. The transcription levels of gene in prophenoloxidase-activating system (proPO), Wnt signaling pathway, phagocytosis, Toll-like system, Ca2+ regulation related process, etc. of SI were significantly changed compare with RI. Finally, 12 selected differentially expressed genes (Serpin, TLR, FZ4, SPI2, Tax1, TLSP, AI, CTLR, Rab11A, LAMP-1, Trx1 and PI3K) were verified using qRT-PCR showed similar tendency with the RNA-seq. The results shown that the proPO, Wnt signaling pathway, phagocytosis, Toll-like system, Ca2+ regulation related process, glutamate signal related process, etc. were involved in the process of the S. eriocheiris infection.