Isolation, Identification And Study Of Molecular Biological Characterizations Of Spodoptera Exigua Nuclear Polyhedrovirus Chinese Strain

A new strain of Nuclear Polyhedrovirus(NPV) was isolated from the beet armyworm, Spodoptera exigua, showing symptoms of NPV infection in Anyang, China. Occlusion bodies produced by this virus isolate, designated as SeMNPV ?CN, measured 1.45 p m in diameter and mostly contained one to four nucleocapsids per envelope. The virus had LC50s of 6.6 X i04 and 2.6 X 1O5PIB/ml to 2nd- and 3rd-instar S. exigua larvae by bioassay, respectively. Restrict endonucleases analysis of viral DNA demonstrated that SeMNPV ?CN, whose genome was about 125.8 kb, was similar to the SeMNPV American isolate. A partial genome library was constructed by shotgun, with 14 of 20 EcoRI-digested patterns cloned into the plasmid pUC 18. Polyhedrin and chitinase genes were amplified by PCR and sequenced. The sequence alignment between SeMNPV-CN and SeMNPV showed that their polyhedrin genes were exactly same, while their chitinase genes had a 98.8% identity and their encoded proteins shared a 99.3% identity. The alignment of 16 chitinase genes from baculo virus and prokaryotic showed that they might come from the same ancestor.