Comparison of white spot syndrome virus structural gene sequences from India with those at GenBank.

Abstract

Outbreaks of viral disease due to white spot syndrome virus (WSSV) in tiger shrimp, Penaeus monodon Fabricius, have been reported since 1994 and they continue to be a major problem for the shrimp aquaculture industry worldwide. White spot syndrome virus is a large and rod shaped with a circular, double-stranded DNA genome that has been comple tely sequenced from the virus isolates of Taiwan (NCBI accession number AF440570), China (NCBI accession number AF332093; Yang, He, Lin, Li, Pan, Zhang & Xu 2001) and Thailand (NCBI accession number AF369029; van Hulten, Witteveldt, Peters, Kloosterboer, Tarchini, Fiers, Sandbrink, Lankhorst & Valk 2001). Alignment of these sequences has re vealed a very high nucleotide identity of 99.32% (Marks, Goldbach,Vlak & van Hulten 2004). The virion envelope contains two major proteins. One isVP28 (28 kDa), suggested to be involved in systemic WSSV infection, and the other VP19 (19 kDa). The nucleocapsid consists of four major proteins, VP26 (26 kDa), VP24 (24 kDa), VP15 (15 kDa) (van Hulten,Witteveldt, Snippe & Vlak 2001) and VP 664 (664 kDa) (Leu, Tsai, Wang, Wang, Wang, Kou & Lo 2005).VP15 is reported to be involved in the packing of theWSSV genome in the nucleocapsid (Witteveldt, Vermeesch, Langenhof, deLang, Valk & van Hulten 2005). However, the assembly of WSSV virus and its detailed structure still remains unclear and requires further study. There have been recent changes in the classification of WSSV structural proteins. For example,VP26, which had been previously classified as nucleocapsid protein, has now been identified as tegument protein distinct from both envelope and nucleocapsid proteins (Xie & Yang 2005; Tsai,Wang)