Characterization of the Polyhedrin Gene of Spodoptera litura Nucleopolyhedrovirus Isolated in Korea

A local strain of Spodoptera litura nucleopolyhedrovirus (SINPV-K1) was isolated from infected larvae of a Korean population of S. litura. Degenerate PCR primer set for the polyhedrin gene successfully amplified the partial polyhedrin gene of SINPV-K1. The sequencing results showed that the about 430 bp PCR product was a fragment of Corresponding polyhedrin gene. Southern blot analysis of SINPV-K1 restriction fragments was performed by using 430 bp polyhedrin PCR product of SINPV-Kl as a probe. As the result, we identified the location of the polyhedrin gene within the approximately 6 kb EcoR I-, 3.5 kb Hind III-, 20 kb Xho I- and 4 kb Cla I-digested fragments, respectively. The Hind III 3.5kb fragment was cloned for sequencing the complete polyhedrin gene. Nucleotide sequence analysis indicated the presence of an open reading frame of 747 nucleotides, which could encode 249 amino acids with a predicted molecular mass of 31 kDa. The nucleotide sequences within the coding region of SINPV-K1 polyhedrin shared maximum 94.0% similarity with the polyhedrin gene from previous reported other SINPVs but were most closely related to Spodoptera littoralis NPV with 99.0% sequence identity. These suggest that the SINPV isolate from Korea is a different SINPV strain.