A Novel Betabaculovirus Isolated from the Monocot Pest Mocis latipes (Lepidoptera: Noctuidae) and the Evolution of Multiple-Copy Genes

Daniel Ardisson-Araújo,Fernando Melo,Daniel Sosa-Gómez,Ana Da Silva,Bergmann Ribeiro,Ethiane Dos Santos

doi:10.3390/v10030134

Abstract

In this report, we described the genome of a novel baculovirus isolated from the monocot insect pest Mocis latipes, the striped grass looper. The genome has 134,272 bp in length with a G + C content of 38.3%. Based on the concatenated sequence of the 38 baculovirus core genes, we found that the virus is a betabaculovirus closely related to the noctuid-infecting betabaculoviruses including Pseudaletia unipuncta granulovirus (PsunGV), Trichoplusia ni granulovirus (TnGV), Helicoverpa armigera granulovirus (HearGV), and Xestia c-nigrum granulovirus (XecnGV). The virus may constitute a new Betabaculovirus species tentatively named Mocis latipes granulovirus (MolaGV). After gene content analysis, five open reading frames (ORFs) were found to be unique to MolaGV and several auxiliary genes were found including iap-3, iap-5, bro-a, bro-b, and three enhancins. The virus genome lacked both chitinase and cathepsin. We then looked at the evolutionary history of the enhancin gene and found that betabaculovirus acquired this gene from an alphabaculovirus followed by several duplication events. Gene duplication also happened to an endonuclease-like gene. Genomic and gene content analyses revealed both a strict collinearity and gene expansion into the genome of the MolaGV-related species. We also characterized the granulin gene using a recombinant Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and found that occlusion bodies were produced into the nucleus of infected cells and presented a polyhedral shape and no occluded virions within. Overall, betabaculovirus genome sequencing is of importance to the field as few genomes are publicly accessible. Mocis latipes is a secondary pest of maize, rice, and wheat crops in Brazil. Certainly, both the discovery and description of novel baculoviruses may lead to development of greener and safer pesticides in order to counteract and effectively control crop damage-causing insect populations

Highlights

The genus Mocis (Lepidoptera: Noctuidae) carries some important polyphagous insects that affect several cultures in many countries of the world [1]
We described the complete genome of a novel betabaculovirus isolated from an insect extract that was kept for several years in a freezer labeled as “Mocis sp. granulovirus” from the virus collection of The Brazilian Agricultural Research Corporation (Portuguese acronym EMBRAPA, Empresa Brasileira de Pesquisa Agropecuária)
Confirming Mocis latipes granulovirus (MolaGV) as a confirming MolaGV as a novel species, we found that the pairwise distances of sequences to other novel species, we found that the pairwise distances of sequences to other betabaculovirus are well in betabaculovirus are well in excess of 0.05 substitutions/site fulfilling the criteria for a novel excess of 0.05 substitutions/site fulfilling the criteria for a novel betabaculovirus species (Table S3)

Summary

Introduction

The genus Mocis (Lepidoptera: Noctuidae) carries some important polyphagous insects that affect several cultures in many countries of the world [1]. These species are widespread throughout the American continent, impacting grasses, wheat, corn, rice, cotton, coffee, soybeans, and peanuts [2]. The GenBank database presents the complete sequence of almost two hundred genomes of baculoviruses with less than half kept as reference of unique species Most of those sequences came from alphabaculovirus (47/73) and the lack of genomic information from the genera Gamma-, Delta- and Betabaculovirus hampers the evolutionary understanding of the Baculoviridae family

Methods

Results

Conclusion