| White spot syndrome viru（sWSSV）is the most destructive virus pathogen whichthreatens the sustainable development of shrimp aquaculture industry. Outbreak ofwhite spot syndrome (WSS) had caused enormous economic lost to the wholeaquaculture industry, so researchers pay more attention to the importance of shrimpimmune research. Research of immune-related genes is necessary and it will help usget further understanding on the immune mechanism of shrimp. On the other hand,searching for effective anti-disease indicators is necessary not only for evaluatingshrimp healthy status but also for genetic breeding. In this study, the full-lengthcDNA of FcIMD was cloned and the function of shrimp IMD was studied. At thesame time, Exopalaemon carinicauda was taken as model shrimp for WSSV infection,and WSSV-tolerant shrimp was obtained by artificial injection of WSSV. Throughanalyzing the activity of the immune related enzymes and transcriptional level ofWSSV infection related genes among WSSV tolerant shrimp (Rm), control shrimp(Vm) and moribund shrimp (Am), some potential indicators for detecting the diseaseresistance are possible to be developed. The main progresses are as follows:A full-length cDNA encoding an IMD homolog (FcIMD) was cloned fromChinese shrimp Fenneropenaeus chinensis. It consists of767bp with a483bp openreading frame encoding160amino acids. A death domain was predicted which iscrucial to the immune function of IMD, and the sequence of FcIMD death domain hashigh samilirity compare with IMD from other kind of shrimps. Tissue expressionanalysis showed that FcIMD mRNA had different expression level in different tissues.The transcriptional expression of FcIMD in shrimp was significantly induced at earlystage (1h) after stimulation by Vibrio or Micrococus and has apparentlyup-regulation and down-regulation at1h and3h after respectively after stimulationby WSSV which suggested its important role in the immunity of shrimp to bacteriuminfection. The expressions of shrimp AMPs were affected when FcIMD was silencedby dsRNA interference. Through analyzing the expression of FcRelish, FcDorsal and FcJNK in FcIMD silenced shrimp, we deduced that IMD was involved in Relishregulated signaling pathway, not in Dorsal or JNK regulated signaling pathway.After WSSV challenge, we got survived Exopalaemon carinicauda asWSSV-tolerant shrimp (named as Rm group), the control shrimp injected with PBSsolution was named as Vm group and moribund shrimp after WSSV infection wasnamed as Am group. We detected the enzyme activity of ACP, AKP, SOD and LZM,which were closely related to the immunity of shrimp. We found that ACP and AKPshowed significant different enzyme activity between Rm and Vm groups. In order toknow whether the shrimp in Rm group has high anti-WSSV activity than shrimp fromVm group, WSSV challenge experiment was performed on the survived Exopalaemoncarinicauda from WSS breakout (named Rn group) and control group (Vn group), wefound that the survival rate of Rn group was higher than Vn group. The resultsuggested that ACP and AKP were possible to be regarded as the potentialanti-WSSV indicator in shrimp.At the transcriptional level，we selected45genes from the transcriptomicanalysis on Exopalaemon carinicauda during WSSV infection which showedsignificant difference in dormant infection and WSSV acute infection group foranalysis among Rm group, Vm group and Am group. The data showed that4geneshave significant different expression level between Vm and Am group. The fourgenes were single VWC domain protein1, triosephosphate isomerase, laminin subunitalpha-like protein and dehydrogenase/reductase SDR family member11-like protein.They might be regarded as potential healthy indicator of shrimp. |
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