The Parapoynx stagnalis nucleopolyhedrovirus (PastNPV), a divergent member of the alphabaculovirus group I clade, encodes a homolog of Ran GTPase

Authors: Harrison, Robert - Bob; Rowley, Daniel

Submitted to: Viruses
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/29/2022
Publication Date: 10/18/2022
Citation: Harrison, R.L., Rowley, D.L. 2022. The Parapoynx stagnalis nucleopolyhedrovirus (PastNPV), a divergent member of the alphabaculovirus group I clade, encodes a homolog of Ran GTPase. Viruses. https://doi.org/10.3390/v14102289.
DOI: https://doi.org/10.3390/v14102289

Interpretive Summary: There is an increasing desire in agriculture to replace chemical insecticides used for pest control with safer, more environmentally friendly options. Consequently, biopesticides based on baculoviruses, which do not infect or cause harm to non-target organisms or the environment, are becoming more popular. Because each baculovirus usually only infects a limited number of pest moth species, there is an interest in identifying baculoviruses with the potential for improved insecticidal activity against a wider array of moth pests. In this study, a baculovirus isolated from a pest of rice called the rice case bearer was examined. The genome sequence of this baculovirus was determined, and differences and similarities between it and other related baculoviruses were enumerated. The information in this study contributes to progress towards developing and improving baculovirus-based insecticides for moth pests of rice, and will be of interest to those in academia, government, and industry who work with this group of insect viruses or with rice pests.

Technical Abstract: We report the analysis of the genome of a novel alphabaculovirus, Parapoynx stagnalis nucleopolyhedrovirus isolate 473 (PastNPV-473), from cadavers of the rice case bearer, Parapoynx stagnalis Zeller (Lepidoptera: Crambidae), collected in rice fields in Kerala, India. High-throughput sequencing of DNA from PastNPV occlusion bodies and assembly of the data yielded a circular genome-length contig of 114,833 bp with 126 annotated opening reading frames (ORFs) and six homologous regions (hrs). Phylogenetic inference based on baculovirus core gene alignments indicated that PastNPV is a member of the group I clade of viruses in genus Alphabaculovirus, but different phylogenetic methods yielded different results with respect to the placement of PastNPV and four similarly divergent alphabaculoviruses - Catopsilia pomona nucleopolyhe-drovirus (CapoNPV), Cyclophragma undans nucleopolyhedrovirus (CyunNPV), Oxyplax ochracea nucleopolyhedrovirus (OxocNPV), and Lonomia obliqua multiple nucleopolyhe-drovirus (LoobMNPV) - in the group I clade. Branch lengths and Kimura-2-parameter pairwise nucleotide distances indicated that PastNPV-473 should be classified as a new species in genus Alphabaculovirus. A unique feature of the PastNPV genome was the presence of an ORF encoding a homolog of Ran GTPase, a regulator of nucleocytoplasmic trafficking.