Genome sequence of an enhancin gene-rich nucleopolyhedrovirus (NPV) from Agrotis segetum: collinearity with Spodoptera exigua multiple NPV

Abstract

The genome sequence of a Polish isolate of Agrotis segetum nucleopolyhedrovirus (AgseNPV-A) was determined and analysed. The circular genome is composed of 147 544 bp and has a G+C content of 45·7 mol%. It contains 153 putative, non-overlapping open reading frames (ORFs) encoding predicted proteins of more than 50 aa, together making up 89·8 % of the genome. The remaining 10·2 % of the DNA constitutes non-coding regions and homologous-repeat regions. One hundred and forty-three AgseNPV-A ORFs are homologues of previously reported baculovirus gene sequences. There are ten unique ORFs and they account for 3 % of the genome in total. All 62 lepidopteran baculovirus genes, including the 29 core baculovirus genes, were found in the AgseNPV-A genome. The gene content and gene order of AgseNPV-A are most similar to those of Spodoptera exigua (Se) multiple NPV and their shared homologous genes are 100 % collinear. Three putative enhancin genes were identified in the AgseNPV-A genome. In phylogenetic analysis, the AgseNPV-A enhancins form a cluster separated from enhancins of the Mamestra species NPVs.