Infection And Highly Effective Diagnosis Of WSSV And Bioinformatics Analysis

The pathogen of White spot syndrome is a kind of rhabdovirus-like virus without viral inclusion body,which is named White spot syndrome virus (WSSV). White spot syndrome has caused tremendous lost to prawn cultivation for its high rate of infection and fatality, besides its widespread hosts.We got a stable infection system by infecting shrimps with sick crayfish troubled with WSSV . Primers are designed based on the WSSV sequence, and PCR reaction was performed with the result of an unknown sequnence, named WSSV ORF 332. Sequence analysis indicated that the sequence homology between WSSV ORF 332 and the corresponding sequence of WSSV from GenBank reached 98%, confirming that WSSV ORF 332 belonged to crayfish WSSV gene fragments.In addition,WSSV in Macrobrachium rosenbergii was detected by PCR , displaying that Macrobrachium rosenbergii is also a natural host of WSSV. ORF 234 could be correctly expressed in E.coli BL21 after cloned, detected by SDS-PAGE and Western blot .We could also gain a similar WSSV band of WSSV ORF 234 in crayshrimp by PCR.Because of the great harm and a broad domain host of WSSV, accurate and sensitive diagnosis of WSSV has a positive meaning for the production of culture. In this study we analyzed regions of the two ORF sequences and designed two series of primers for loop-mediated isothermal amplification method for testing WSSV, The result is that two sets can all amplify expected bands, the temperature is the key factor of LAMP. The sensitiveness of ORF 234 by LAMP is almost ten thousand times more than that by PCR, LMAP has a good prospect of application and dissemination for its short time within 1.5 hours, high sensitivity,non-false positive and simple needs for equipments.We chose several WSSV gene fragments for codon preference analysis. The results which showed that CAI was low, FOP approached 0.4 , most CBI was negative value , indicated that the optimum number of codon was less than that expected, pointing out that the Codon preference was low , which was perhaps one of the reasons of wide range of host.