Genomic analysis of a Trichoplusia ni Betabaculovirus (TnGV) with three different viral enhancing factors and two unique genes

Abstract

The complete genome of a Trichoplusia ni granulovirus (TnGV) is described and analyzed. The genome contains 175,360 bp (KU752557), becoming the third largest genome within the genus Betabaculovirus, smaller only than the Xestia c-nigrum GV (XecnGV) (178,733 pb) and the Pseudaletia unipuncta GV (PsunGV) (176,677 pb) genomes. The TnGV genome has a 39.81% C+G content and a total of 180 ORFs were identified, 96 of them in the granulin gene direction and 84 in the opposite direction. A total of 94.38% of the ORFs showed high identity with those of ClanGV, HaGV, and SlGV. Eight homologous regions (hrs) were identified as well as one apoptosis inhibitor (IAP-3). Interestingly, three viral enhancing factors (VEFs) were located in TnGV genome: VEF-1 (orf153), VEF-3 (orf155), and VEF-4 (orf164), additional to another metalloprotease (orf37). Two ORFs were unique to TnGV (orf100 and orf101) and another one was shared by only TnGV and AgseGV (orf2). Eleven of the deduced proteins showed high identity with proteins from nucleopolyhedroviruses, three with proteins from ascoviruses, and one with an entomopoxvirus protein. The largest deduced protein contains 1,213 amino acids (orf43) and the smallest deduced protein contains only 50 amino acids (orf143). Sequence identity and phylogenetic analyses showed that the closest related genomes to TnGV are, to date, those of PsunGV and XecnGV. This genome analysis may contribute to functional research on TnGV, and may form the bases for the utilization of this betabaculovirus as a pest control agent.

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

“…The MolaGV genome presents three enhancins . In a recent work describing the genome of the Trichoplusia ni granulovirus (TnGV), three enhancin genes were also observed [ 24 ]. The enhancins were described firstly in betabaculoviruses [ 25 , 26 ] and later found in some alphabaculoviruses (e.g., Choristoneura fumiferana multiple nucleopolyhedrovirus (CfMNPV), Choristoneura occidentalis nucleopolyhedrovirus (ChocNPV), Choristoneura rosaceana nucleopolyhedrovirus (ChroNPV), Dendrolimus kikuchii nucleopolyhedrovirus (DekiNPV), Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV), Lymantria xylina nucleopolyhedrovirus (LyxyMNPV), Mamestra configurata nucleopolyhedrovirus B (MacoNPV-B), Agrotis segetum nucleopolyhedrovirus B (AgseNPV-B) [ 27 , 28 ].…”

Bacmid Expression of Granulovirus Enhancin En3 Accumulates in Cell Soluble Fraction to Potentiate Nucleopolyhedrovirus Infection

“…For the construction of the recombinant virus expressing the enhancin gene, the Bac-to-Bac TM Baculovirus Expression System was used (ThermoFisher Scientific, Waltham, MA, USA). The enhancin gene was amplified from Trichoplusia ni granulovirus (TnGV) [ 16 ], whereas the polyhedrin gene was amplified from the AcMNPV C6 clone, the type species of the Alphabaculovirus genus [ 25 ]. All viruses were obtained from the virus collection of the Microbial Bioinsecticides group at the Universidad Pública de Navarra.…”

“…We selected enhancin 3 (En3) of TnGV to construct the recombinant virus as TnGV-purified enhancins produced the highest potentiation (discussed in Appendix A ). Among the three enhancins present in the TnGV genome [ 16 ], En3 possesses both the zinc-binding domain of metalloproteinases and the mucin-binding domain ( Figure S1 ) (explained in Appendix B ).…”

“…In contrast, orthologues present in lepidopteran-infecting nucleopolyhedroviruses (NPV, genus Alphabaculovirus ) are associated with ODV envelopes and their efficacy as enhancers of NPV infections has come from experiments with recombinant viruses [ 6 , 13 , 14 , 15 ]. Some betabaculovirus and alphabaculovirus genomes contain multiple copies of these genes [ 13 , 14 , 15 , 16 ].…”

“…A protein analysis was performed to identify the presence of active domains in TnGV enhancins. Three enhancins have been identified in the genome [ 16 ], and a conserved domain search was performed with NBCI batch Web CD-Search Tool [ 52 ] in order to select one to construct the recombinant AcMNPV. De novo discovery of motifs was carried out using MEME suite [ 53 ].…”