Whole genome analysis of a novel Spodoptera exigua nucleopolyhedrovirus isolate (SeMNPV-IR) to Iran.

Baculoviruses are successful microbial control agents used in the biological control of agricultural pest species, especially in the order Lepidoptera. The beet armyworm, Spodoptera exigua is a popular agricultural pest in the world. S exigua larvae, which are active in the all-summer period, cause economic losses by damaging many crops in agricultural production areas. This article aims to analyze the full genome of Spodoptera exigua multiple nucleopolyhedroviruses from Iran (SeMNPV-IR) and to determine the geographical difference between the strains at the genomic level. The full genome of SeMNPV-IR is 135.764 base pairs in length that contained 136 open reading frames (ORFs), and 43.92% G + C content. The seven homologous repeated (hr) regions were identified. In the results of genome-wide phylogenetic analysis, it was determined that the SeMNPV-IR genome isolated from Iran was interestingly close to the genome of the US and Korea isolates. However, there are significant differences in the two hypothetical (Orf 83 and Orf 104) genes. The SeMNPV-IR has a unique homolog repeat region (hr1, 96 bp) that is not found in other SeMNPV genomes, and it also differs in terms of the hr2 region. In silico restriction endonuclease analysis by StuI and SacII enzymes show that there were significant differences between all geographic isolates of SeMNPV. Supplementary Information: The online version contains supplementary material available at 10.1007/s11756-023-01399-2.

Genome sequence analysis of a Helicoverpa armigera single nucleopolyhedrovirus (HearNPV-TR) isolated from Heliothis peltigera in Turkey.

The entire genome of Helicoverpa armigera single nucleopolyhedrovirus (HearNPV-TR) was sequenced, and compared to genomes of other existing isolates. HearNPV-TR genome is 130.691 base pairs with a 38.9% G+C content and has 137 open reading frames (ORFs) of ≥ 150 nucleotides. Five homologous repeated sequences (hrs) and two baculovirus repeated ORFs (bro-a and bro-b) were identified. Phylogenetic analysis showed that HearNPV-TR is closer to HaSNPV-C1, HaSNPV-G4, HaSNPV-AU and HasNPV. However, there are significant differences in hr3, hr5 regions and in bro-a gene. Pairwise Kimura-2 parameter analysis of 38 core genes sequences of HearNPV-TR and other Helicoverpa NPVs showed that the genetic distances for these sequences were below 0.015 substitutions/site. Genomic differences as revealed by restriction profiles indicated that hr3, hr5 regions and bro-a gene may play a role in the virulence of HearNPV-TR.

A new Helicoverpa armigera Nucleopolyhedrovirus isolate from Heliothis peltigera (Denis & Schiffermuller) (Lepidoptera: Noctuidae) in Turkey.

This study reports a new Helicoverpa armigera nucleopolyhedrovirus (NPV) isolated from Heliothis peltigera (Denis & Schiffermuller), collected in the vicinity of Adana, Turkey. Infection was confirmed by tissue polymerase chain reaction and sequence analysis. Results showed that dead H. peltigera larvae contain Helicoverpa armigera nucleopolyhedrovirus. Thus, the isolate was named as HearNPV-TR. Microscopy studies indicated that occlusion bodies were 0.73 to 1.66 µm in diameter. The nucleocapsids are approximately 184 × 41 nm in size. The genome of HearNPV-TR was digested with KpnI and XhoI enzymes and calculated as 130.5 kb. Phylogenetic analysis showed that HearNPV-TR has close relation with the H. armigera SNPV-1073 China isolate. The Kimura analysis confirmed that the isolate is a variant of H. armigera NPV. Bioassays were performed using six different concentrations (1 × 103 to 1 × 108 occlusion bodies (OBs)/mL) on 2nd instar larvae of H. peltigera, H. armigera, Heliothis viriplaca, Heliothis nubigera. LC50 values were calculated to be 9.5 × 103, 1.9 × 104, 8.6 × 104 and 9.2 × 104 OBs/mL within 14 days, respectively. Results showed that it is a promising biocontrol agent against Heliothinae species.