Leucoma salicis nucleopolyhedrovirus (LesaNPV) genome sequence shed new light on the origin of the Alphabaculovirus orpseudotsugatae species.

LesaNPV (Leucoma salicis nucleopolyhedrovirus) is an alphabaculovirus group Ib. Potentially, it can be an eco-friendly agent to control the white satin moth Leucoma salicis population. In this study, we have established the relationship between LesaNPV and other closely related alphabaculoviruses. Environmental samples of late instar of white satin moth collected in Poland infected with baculovirus have been homogenized, polyhedra were purified and subjected to scanning and transmission electron microscopy. Viral DNA was sequenced using the Illumina platform and the whole-genome sequence was established by de novo assembly of paired reads. Genome annotation and phylogenetic analyses were performed with the use of bioinformatics tools. The genome of LesaNPV is 132 549 bp long with 154 ORFs and 54.9% GC content. Whole-genome sequencing revealed deletion of dUTPase as well as ribonucleoside reductases small and large subunits region in LesaNPV genome compared to Dasychira pudibunda nucleopolyhedrovirus (DapuNPV) and Orgyia pseudotsugata multiple nucleopolyhedrovirus (OpMNPV) where this region is complete. Phylogenetic analysis of Baculoviridae family members showed that LesaNPV is less divergent from a common ancestor than closely related species DapuNPV and OpMNPV. This is interesting because their hosts do not occur in the same area. The baculoviruses described in this manuscript are probably isolates of one species and could be assigned to recently denominated species Alphabaculovirus orpseudotsugatae, historically originating from OpMNPV. This finding could have significant implications for the classification and understanding of the phylogeographical spread of baculoviruses.

Entomopathogens in the integrated management of forest insects: from science to practice.

The most important aim of the integrated management of forest insect pests remains the prevention of insect outbreaks, which are a consequence of the interaction of many factors in forest ecosystems, including species composition, age and health of the forest, soil type, the presence of natural enemies, and climatic factors. Integrated pest management until now has been achieved using measures aimed at shaping the functioning of stands in a changing environment. The aim of this review is to summarize research on the use of entomopathogens (microorganisms and nematodes) in the management of forest insect pests and to identify the principal knowledge gaps. We briefly describe the main research directions on the use of pathogens and nematodes to control insect pests and discuss limitations affecting their implementation. Research on entomopathogens for the biocontrol of forest insects has provided a wealth of knowledge that can be used effectively to reduce insect populations. Despite this, few entomopathogens are currently used in integrated pest management in forestry. They are applied in inoculation or inundation biocontrol strategies. While the use of entomopathogens in forest pest management shows great promise, practical implementation remains a distant goal. Consequently, sustainable reduction of forest pests, mainly native species, will be largely based on conservation biological control, which aims to modify the environment to favor the activity of natural enemies that regulate pest populations. This type of biocontrol can be supported by a range of silvicultural measures to increase the resilience of stands to insect infestations. © 2023 Society of Chemical Industry.

Complete Genome Sequence of Lymantria dispar multiple nucleopolyhedrovirus Isolated in Southwestern Poland.

We report here the complete genomic sequence of Polish alphabaculovirus isolated from dead gypsy moth caterpillars. Its genome structure and G+C content indicate that it is a Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV) strain which possesses the shortest sequence among eight other (similar to reference sequence AF081810) LdMNPV sequences available in GenBank; it is 159,729 bp long.

An alphabaculovirus isolated from dead Lymantria dispar larvae shows high genetic similarity to baculovirus previously isolated from Lymantria monacha - An example of adaptation to a new host.

A new isolate of baculovirus, Lymantria dispar multiple nucleopolyhedrovirus-BNP (LdMNPV-BNP), was found in dead gypsy moth (L. dispar) caterpillars collected in the Biebrzanski National Park in Poland. Here, we examined its biological activity, structure, genetic content and phylogeny. Multiple nucleocapsids of LdMNPV-BNP are enveloped together in 2-26 virions embedded in occluded bodies (OBs) very similar to the OBs previously described in viruses infecting Lymantriinae. This isolate kills pest larvae in a relatively short time (LT50 of approximately 9days for a dose of 2×10(7)OBs/ml), highlighting the possibility for its use as a biopesticide. Next-generation sequencing of LdMNPV-BNP revealed gene content (e.g. DNA photolyase) that is not present in any LdMNPV isolate sequenced to date. The genome is 157,270 base pairs long and has a notably lower G+C content in comparison to other LdMNPVs (50.3% G+C content compared to an average of 57.4% among other LdMNPVs). According to our phylogenetic analysis based on 37 core genes, LdMNPV-BNP is a member of group II alphabaculoviruses, which are closely related to LdMNPV and LyxyMNPV (Lymantria xylina multiple nucleopolyhedrovirus). Molecular evolution inference based on the partial sequence of lef-8, lef-9 and polh genes shows that LdMNPV-BNP and isolates of Lymantria monacha nucleopolyhedrovirus (LymoNPV) may share a very recent common ancestor or be isolates of the same virus species. LdMNPV-BNP, like other baculoviruses, could be beneficial as an active component of biopesticides that can be used during forest integrated pest management.

Occurrence of entomopathogenic nematodes in Polish soils / Ocorrência de nematoides entomopatogênicos em solos da Polônia

ABSTRACT: Entomopathogenic nematodes ( Steinernematidaeand Heterorhabditidae) were studied in Polish soils according to the: season, habitat and altitude. In total, 167 soil samples were taken from 111 localities in Poland along north-south transect. Entomopathogenic nematodes were isolated from 53 soil samples (31.7%). Nematodes species were identified genetically from 16 samples, and in all other 37 samples nematodes were determined to the genus level. Three species of the genus Steinernema ( Steinernema kraussei, S. feltiae, S. carpocapsae) and one of the genus Heterorhabditis( Heterorhabditis megidis) were recorded. Steinernema feltiaewas the most common species. There was not a significant association between the occurrence of nematodes and season or altitude. The type of habitat significantly (P<0.05) affected the occurrence of nematodes. Nematodes were most frequent in samples collected from coniferous forests (20 findings).

RESUMO: Os nematoides entomopatogênicos ( Steinernematidaee Heterorhabditidae) foram estudados em solo polonês de acordo com estação, habitat e altitude. Foram coletadas um total de 167 amostras de solo em 111 localidades diferentes ao longo da trajeto Norte-Sul da Polônia. Os nematoides entomopatogênicos foram extraídos em 53 das amostras de solo (31,7%). As espécies de nematoides foram geneticamente identificadas a partir de 16 amostras, as outras 37 amostras foram usadas para determinar o gênero. Três espécies do gênero Steinernema( Steinernema kraussei, S. feltiae, S. carpocapsae) e uma espécie do gênero Heterorhabditis( Heterorhabditis megidis) foram identificadas. A espécie mais comum foi a S. feltiae. Não foi encontrada uma relação significativa entre a presença de nematoides com a estação do ano e a altitude. O tipo de habitat afetou significativamente (P<0,05) a ocorrência de nematoides. Os nematoides foram encontrados mais frequentemente em amostras recolhidas em florestas de coníferas (20 no total).

The genome of Dasychira pudibunda nucleopolyhedrovirus (DapuNPV) reveals novel genetic connection between baculoviruses infecting moths of the Lymantriidae family.

BACKGROUND: DapuNPV (Dasychira pudibunda nucleopolyhedrovirus), presented in this report, belongs to Alphabaculovirus group Ib. Its full, newly sequenced genome shows close relationship to baculovirus OpMNPV isolated from douglas-fir tussock moth Orgyia pseudotsugata. Baculovirus DapuNPV is a natural limiter of pale tussock moth Dasychira pudibunda L. (syn. Calliteara pudibunda L.)(Lepidoptera, Lymantriidae), which can occur in a form of an outbreak on many species of deciduous trees and may cause significant economic losses in the forests. METHODS: Late instars dead larvae of pale tussock moth were mechanically homogenized and polyhedra were purified during series of ultracentrifugation. Viral DNA was extarcted and sequenced using Miseq Illumina platform. 294,902 paired reads were used for de novo assembling. Genome annotation, multiple allingment to others baculoviruses and phylogegentic analises were perform with the use of multiple bioinformatic tools like: Glimmer3, HMMER web server, Geneious 7 and MEGA6. RESULTS: The genome of DapuNPV is 136,761 bp long with AT pairs content 45.6 %. The predicted number of encoded putative open reading frames (ORFs) is 161 and six of them demonstrate low or no homology to ORFs previously found in baculoviruses. DapuNPV genome shows very high similarity to OpMNPV in a nucleotide sequence (91.1 % of identity) and gene content (150 homologous ORFs), though some major differences (e.g. lack of he65 in OpMNPV) have also been noted. CONCLUSIONS: Similarly to other members of the Baculoviridae family, DapuNPV baculovirus possesses highly conserved core genes. Among them, there is a second copy of occluded derived virus envelope 27 protein (odv-e27), which was previously found only in a member of Alphabaculovirus group II - LyxyMNPV (Lymantria xylina MNPV). Surprisingly enough, DapuNPV and LyxyMNPV genomes share also another feature. Phylogenetic analysis of chitin binding family protein (cbpl) indicates significant similarity of those two baculoviruses from distinct evolutionary groups which infect the same hosts from Lymantriidae. The ubiquitin like family gene (ubil), which has not been described until now, is another characteristic component of DapuNPV genome.

The effect of initial dose on the recovery and final yields of Heterorhabditis megidis (Rhabditida: Heterorhabditidae) in larvae of the great wax moth, Galleria mellonella.

The aim of this study was to determine the effect of different initial doses of the infective juveniles (IJs) (50 IJs, 200 IJs, 1000 IJs) of Heterorhabditis megidis Poinar (Rhabditida: Heterorhabditidae) strain IsM15/09 on recovery, final yields and percent final yields in larvae Galleria mellonella ( L.). Percent recovery was not directly related to initial dose. Final yields also did not change with the initial dose. However, percent yields was highly negatively correlated with initial dose of nematodes and was the highest with the 50 IJs dose. Additional point of the study was to investigate whether the nematodes are able to produce progeny from one hermaphroditic individual. The results showed that the invasive larvae resumed growth and transformed into hermaphroditic individuals that reproduced without cross-fertilisation.

Detection and identification of baculovirus pesticides by multitemperature single-strand conformational polymorphism.

The method of single-strand conformational polymorphism (SSCP) was modified in our laboratories for the characterization of baculoviruses, insect viruses with great potential for use as bioinsecticides in biological protection programs. A series of primers were synthesized after the comparison of the polyhedrin gene sequences of over 20 baculoviruses. Polyhedrin is a highly conserved protein which is responsible for the persistence of the virus in the environment. Universal primers were designed which could be used in polymerase chain reactions (PCR) containing genomic DNA from an array of nucleopolyhedrosis viruses (NPVs) including these which are used as biopesticides against important pests of forests and crops, such as Anticarsia gemmatalis, Spodoptera frugiperda, Lymantria dispar, Lymantria monacha and many others. PCR products were denatured and subjected to single-strand DNA electrophoresis at variable temperatures (MSSCP) where, after silver staining, they gave ssDNA band patterns characteristic for each baculovirus species. This technique can be potentially applied to detect baculoviruses in insects collected in the field, as well as to plant tissues and the excrements or bodies of predators without need for sequencing the PCR products. Sometimes MSSCP can be used not only for species determination but also as an indication of genomic variability which can be related to infectivity.

Baculoviruses-- re-emerging biopesticides.

Biological control of agricultural pests has gained importance in recent years due to increased pressure to reduce the use of agrochemicals and their residues in the environment and food. Viruses of a few families are known to infect insects but only those belonging to the highly specialized family Baculoviridae have been used as biopesticides. They are safe to people and wildlife, their specificity is very narrow. Their application as bioinsecticides was limited until recently because of their slow killing action and technical difficulties for in vitro commercial production. Two approaches for the wider application of baculoviruses as biopesticides will be implemented in future. In countries where use of genetically modified organisms is restricted, the improvements will be mainly at the level of diagnostics, in vitro production and changes in biopesticide formulations. In the second approach, the killing activity of baculoviruses may be augmented by genetic modifications of the baculovirus genome with genes of another natural pathogen. It is expected that the baculoviruses improved by genetic modifications will be gradually introduced in countries which have fewer concerns towards genetically modified organisms.

Decompaction and recompaction of mouse preimplantation embryos.

Early (non-compacted) and late (compacted) 8-cell embryos were observed after few hours of culture in vitro. The former embryos underwent compaction and the latter embryos were found decompacted. Cell counting suggested that decompaction preceded fourth cleavage division of any blastomere and lasted until the blastomeres divided.About one third of mouse morulae, which had about twenty cells, were found non-compacted upon obtaining from females. After few hours of culture in vitro these embryos underwent recompaction and cavitation. Increasing the contributions of mitosis-arrested and cytokinesisarrested cells within the morulae by culture with nocodazole and cytochalasin B respectively, did not delay recompaction.The data show that periods of decompaction and recompaction alternate in preimplantation development.