RESUMO
Cydia pomonella granulovirus is a natural pathogen for Cydia pomonella that is used as a biocontrol agent of insect populations. The study of granulovirus virulence is of particular interest since the development of resistance in natural populations of C. pomonella has been observed during the long-term use of the Mexican isolate CpGV. In our study, we present the genomes of 18 CpGV strains endemic to southern Russia and from Kazakhstan, as well as a strain included in the commercial preparation "Madex Twin", which were sequenced and analyzed. We performed comparative genomic analysis using several tools. From comparisons at the level of genes and protein products that are involved in the infection process of virosis, synonymous and missense substitution variants have been identified. The average nucleotide identity has demonstrated a high similarity with other granulovirus genomes of different geographic origins. Whole-genome alignment of the 18 genomes relative to the reference revealed regions of low similarity. Analysis of gene repertoire variation has shown that BZR GV 4, BZR GV 6, and BZR GV L-7 strains have been the closest in gene content to the commercial "Madex Twin" strain. We have confirmed two deletions using read depth coverage data in regions lacking genes shown by homology analysis for granuloviruses BZR GV L-4 and BZR GV L-6; however, they are not related to the known genes causing viral pathogenicity. Thus, we have isolated novel CpGV strains and analyzed their potential as strains producing highly effective bioinsecticides against C. pomonella.
Assuntos
Genoma Viral , Granulovirus , Mariposas , Filogenia , Granulovirus/genética , Granulovirus/patogenicidade , Granulovirus/classificação , Animais , Mariposas/virologia , Anotação de Sequência MolecularRESUMO
Cnaphalocrocis medinalis granulovirus (CnmeGV), belonging to Betabaculovirus cnamedinalis, can infect the rice pest, the rice leaf roller. In 1979, a CnmeGV isolate, CnmeGV-EP, was collected from Enping County, China. In 2014, we collected another CnmeGV isolate, CnmeGV-EPDH3, at the same location and obtained the complete virus genome sequence using Illumina and ONT sequencing technologies. By combining these two virus isolates, we updated the genome annotation of CnmeGV and conducted an in-depth analysis of its genome features. CnmeGV genome contains abundant tandem repeat sequences, and the repeating units in the homologous regions (hrs) exhibit overlapping and nested patterns. The genetic variations within EPDH3 population show the high stability of CnmeGV genome, and tandem repeats are the only region of high genetic variation in CnmeGV genome replication. Some defective viral genomes formed by recombination were found within the population. Comparison analysis of the two virus isolates collected from Enping showed that the proteins encoded by the CnmeGV-specific genes were less conserved relative to the baculovirus core genes. At the genomic level, there are a large number of SNPs and InDels between the two virus isolates, especially in and around the bro genes and hrs. Additionally, we discovered that CnmeGV acquired a segment of non-ORF sequence from its host, which does not provide any new proteins but rather serves as redundant genetic material integrated into the viral genome. Furthermore, we observed that the host's transposon piggyBac has inserted into some virus genes. Together, dsDNA viruses could acquire non-coding genetic material from their hosts to expand the size of their genomes. These findings provide new insights into the evolution of dsDNA viruses.
Assuntos
Variação Genética , Genoma Viral , Animais , Filogenia , China , Granulovirus/genética , Granulovirus/classificação , Granulovirus/isolamento & purificação , Sequenciamento Completo do Genoma , Oryza/virologia , Sequências de Repetição em Tandem/genética , Doenças das Plantas/virologia , Recombinação GenéticaRESUMO
Spodoptera ornithogalli (Guenée) (Lepidoptera: Noctuidae) is an important pest in different crops of economic relevance in America. For its control, strategies that include chemicals are usually used; so, the description of entomopathogens would be very useful for the formulation of biopesticides. In this regard, two different baculoviruses affecting S. ornithogalli were isolated in Colombia, with one of them being an NPV and the other a GV. Ultrastructural, molecular, and biological characterization showed that both isolates possess the 38 core genes and are novel species in Baculoviridae, named as Spodoptera ornithogalli nucleopolyhedrovirus (SporNPV) and Spodoptera ornithogalli granulovirus (SporGV). The bioassays carried out in larvae of S. ornithogalli and S. frugiperda showed infectivity in both hosts but being higher in the first. In addition, it was observed that SporGV potentiates the insecticidal action of SporNPV (maximum value in ratio 2.5:97.5). Both viruses are individually infective but coexist in nature, producing mixed infections with a synergistic effect that improves the performance of the NPV and enables the transmission of the GV, which presents a slowly killing phenotype.
Assuntos
Baculoviridae , Coinfecção/virologia , Larva/virologia , Spodoptera/virologia , Animais , Baculoviridae/genética , Agentes de Controle Biológico , Colômbia , Modelos Animais de Doenças , Granulovirus/classificação , Granulovirus/genética , Inseticidas , Mariposas/virologia , Nucleopoliedrovírus , Controle Biológico de Vetores , FilogeniaRESUMO
Cydia pomonella granulovirus (CpGV) is a widely used biological control agent of the codling moth. Recently, however, the codling moth has developed different types of field resistance against CpGV isolates. Whereas type I resistance is Z chromosomal inherited and targeted at the viral gene pe38 of isolate CpGV-M, type II resistance is autosomal inherited and targeted against isolates CpGV-M and CpGV-S. Here, we report that mixtures of CpGV-M and CpGV-S fail to break type II resistance and is expressed at all larval stages. Budded virus (BV) injection experiments circumventing initial midgut infection provided evidence that resistance against CpGV-S is midgut-related, though fluorescence dequenching assay using rhodamine-18 labeled occlusion derived viruses (ODV) could not fully elucidate whether the receptor binding or an intracellular midgut factor is involved. From our peroral and intra-hemocoel infection experiments, we conclude that two different (but genetically linked) resistance mechanisms are responsible for type II resistance in the codling moth: resistance against CpGV-M is systemic whereas a second and/or additional resistance mechanism against CpGV-S is located in the midgut of CpR5M larvae.
Assuntos
Resistência à Doença/genética , Granulovirus/fisiologia , Larva/genética , Larva/virologia , Mariposas/genética , Mariposas/virologia , Animais , Bioensaio , Agentes de Controle Biológico , Trato Gastrointestinal , Granulovirus/classificação , Larva/anatomia & histologia , Mariposas/classificaçãoRESUMO
The baculovirus Cydia pomonella granulovirus (CpGV) is a biocontrol agent used worldwide against the codling moth (CM), Cydia pomonella L., a severe pest in organic and integrated pome fruit production. Its successful application is increasingly challenged by the occurrence of CM populations resistant to commercial CpGV products. Whereas three types (I-III) of CpGV resistance have been identified, type I resistance compromising the efficacy of CpGV-M, the so-called Mexican isolate of CpGV, is assumed to be the most widely distributed resistance type in Central Europe. Despite the wide use of CpGV products as biocontrol agents, little information is available on gene-expression levels in CM larvae. In this study, the in vivo transcriptome of CpGV-M infecting susceptible (CpS) and resistant (CpRR1) CM larvae was analysed at 24, 48, 72, 96 and 120 hours post infection in the midgut and fat body tissue by using a newly developed microarray covering all ORFs of the CpGV genome. According to their transcript abundance, the CpGV genes were grouped into four temporal clusters to which groups of known and unknown function could be assigned. In addition, sets of genes differentially expressed in the midgut and fat body were found in infected susceptible CpS larvae. For the resistant CpRR1 larvae treated with CpGV-M, viral entry in midgut cells could be confirmed from onset but a significantly reduced gene expression, indicating that type I resistance is associated with a block of viral gene transcription and replication.
Assuntos
Granulovirus/genética , Granulovirus/isolamento & purificação , Mariposas/virologia , Transcriptoma , Animais , Europa (Continente) , Granulovirus/classificação , Granulovirus/fisiologia , Larva/imunologia , Larva/virologia , Mariposas/crescimento & desenvolvimento , Mariposas/imunologia , Doenças das Plantas/parasitologiaRESUMO
The co-evolution between baculoviruses and their insect hosts results in selection of virus populations. To explore this phenomenon at the molecular level, seven natural isolates of Cydia pomonella granulovirus (CpGV) collected from orchards in northwest China were studied using Illumina next generation sequencing (NGS). A total of 540 genome positions with single nucleotide polymorphisms (SNPs) were detected in comparison with known CpGV isolates. New members of previously defined phylogenetic genome groups A, D and E of CpGV, as well as two novel phylogenetic lines, termed genome group F and G, were identified. Combining SNP frequency distribution with the prevalence of genome group-specific SNPs, revealed that six isolates of CpGV were mixtures of different ratios of at least two genotypes, whereas only one isolate, CpGV-WW, was genetically highly homogeneous. This study significantly extends our current understanding of the genetic diversity of CpGV and opens new lines of application of this virus.
Assuntos
Granulovirus/genética , Polimorfismo de Nucleotídeo Único , Animais , Genoma Viral , Granulovirus/classificação , FilogeniaRESUMO
The fall webworm (Hyphantria cunea) impacts a wide variety of crops and cultivated broadleaf plant species. The pest is native to North America, was introduced to Europe and has since spread further as far as central Asia. Despite several attempts to control its distribution, the pest continues to spread causing damage all over the world. A naturally occurring baculovirus, Hyphantria cunea granulovirus (HycuGV-Hc1), isolated from the larvae of H. cunea in Turkey appears to have a potential as microbial control agent against this pest. In this report we describe the complete genome sequence and organization of the granulovirus isolate (HycuGV-Hc1) that infects the larval stages and compare it to other baculovirus genomes. The HycuGV-Hc1 genome is a circular double-stranded DNA of 114,825â¯bp in size with a nucleotide distribution of 39.3% Gâ¯+â¯C. Bioinformatics analysis predicted 132 putative open reading frames of (ORFs)â¯≥â¯150 nucleotides. There are 24 ORFs with unknown function. Seven homologous repeated regions (hrs) and two bro genes (bro-1 and bro-2) were identified in the genome. Comparison to other baculovirus genomes, HycuGV-Hc1 revealed some differences in gene content and organization. Gene parity plots and phylogenetics confirmed that HycuGV-Hc1 is a Betabaculovirus and is closely related to Plutella xylostella granulovirus. This study expands our knowledge on the genetic variation of HycuGV isolates and provides further novel knowledge on the nature of granuloviruses.
Assuntos
Genoma Viral , Granulovirus/genética , Animais , Composição de Bases , DNA Viral/química , Genes Virais , Granulovirus/classificação , Mariposas/virologia , Fases de Leitura Aberta , Filogenia , Análise de Sequência de DNA , TurquiaRESUMO
Cydia pomonella granulovirus, in particular CpGV-M isolate, is used as a biological control against the codling moth (CM), Cydia pomonella. As a result of intensive control over the years, codling moth populations have developed resistance against this isolate. This resistance is now called type I resistance. Isolates, among them, CpGV-R5, have been found that are able to overcome type I resistance. Both CpGV-M and CpGV-R5 are used in orchards to control the codling moth. High resolution melting (HRM) has been adapted to differentiate between CpGV-M and CpGV-R5 isolates. Specific PCR primers have been designed for the CpGV p38 gene, encompassing the variable region responsible for the ability to overcome resistance. Because each amplicon has a specific melting point, it is possible to identify the CpGV-M and CpGV-R5 genotypes and to quantify their relative proportion. This method has been validated using mixtures of occlusion bodies of each isolate at various proportions. Then, the HRM has been used to estimate the proportion of each genotype in infected larvae or in occlusion bodies (OBs) extracted from dead larvae. This method allows a rapid detection of genotype replication and enables the assessment of either success or failure of the infection in field conditions.
Assuntos
Genótipo , Granulovirus/classificação , Granulovirus/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Reação em Cadeia da Polimerase em Tempo Real , Animais , Hemolinfa/virologia , Larva/virologia , Técnicas de Amplificação de Ácido Nucleico/normas , Reação em Cadeia da Polimerase em Tempo Real/métodos , Reação em Cadeia da Polimerase em Tempo Real/normas , Temperatura de Transição , Proteínas Virais/genéticaRESUMO
The complete genome of an endemic South African Cydia pomonella granulovirus isolate was sequenced and analyzed. Several missing or truncated open reading frames (ORFs) were identified, including a 24 bp deletion in the pe38 gene which is reported to be associated with type I resistance-breaking potential. Comparison of single nucleotide polymorphisms (SNPs) with five other fully sequenced CpGV isolates identified 67 unique events, 47 of which occurred within ORFs, leading to several amino acid changes. Further analysis of single nucleotide variations (SNVs) within CpGV-SA revealed that this isolate consists of mixed genotypes. Phylogenetic analysis using complete genome sequences placed CpGV-SA basal to M, I12 and E2 and distal to S and I07 but with no distinct classification into any of the previously defined CpGV genogroups. These results suggest that CpGV-SA is a novel and genetically distinct isolate with significant potential as a biopesticide for management of codling moth (CM), not only in South Africa, but potentially in other pome fruit producing countries, particularly where CM resistance to CpGV has been reported.
Assuntos
Genoma Viral , Genômica , Granulovirus/classificação , Granulovirus/genética , Interações Hospedeiro-Patógeno , Mariposas/virologia , Animais , Genômica/métodos , Genótipo , Filogenia , Polimorfismo de Nucleotídeo ÚnicoRESUMO
Virus infections of insects can easily stay undetected, neither showing typical signs of a disease, nor being lethal. Such a stable and most of the time covert infection with Phthorimaea operculella granulovirus (PhopGV) was detected in a Phthorimaea operculella laboratory colony, which originated from Italy (Phop-IT). This covert virus (named PhopGV-R) was isolated, purified and characterized at the genetic level by full genome sequencing. Furthermore, the insect colony Phop-IT was used to study the crowding effect, double infection with other PhopGV isolates (CR3 and GR1), and co-infection exclusion. An infection with a second homologous virus (PhopGV-CR3) activated the covert virus, while a co-infection with another virus isolate (PhopGV-GR1) led to its suppression. This study shows that stable virus infections can be common for insect populations and have an impact on population dynamics because they can suppress or enable co-infection with another virus isolate of the same species.
Assuntos
Animais de Laboratório/virologia , Granulovirus/crescimento & desenvolvimento , Granulovirus/isolamento & purificação , Lepidópteros/virologia , Animais , Animais de Laboratório/crescimento & desenvolvimento , Comportamento Animal , Granulovirus/classificação , Granulovirus/genética , Itália , Lepidópteros/crescimento & desenvolvimento , Dinâmica Populacional , Sequenciamento Completo do GenomaRESUMO
Baculoviridae is a highly diverse family of rod-shaped viruses with double-stranded DNA. To date, almost 100 species have had their complete genomic sequences deposited in the GenBank database, a quarter of which comprises granuloviruses (GVs). Many of the genomes are sequenced using next-generation sequencing, which is currently considered the best method for characterizing new species, but it is time-consuming and expensive. Baculoviruses form a safe alternative to overused chemical pesticides and therefore there is a constant need for identifying new species that can be active components of novel biological insecticides. In this study, we have described a fast and reliable method for the detection of new and differentiation of previously analyzed granulovirus species based on a real-time polymerase chain reaction (PCR) technique with melting point curve analysis. The sequences of highly conserved baculovirus genes, such as granulin and late expression factors 8 and 9 (lef-8 and lef-9), derived from GVs available to date have been analyzed and used for degenerate primer design. The developed method was tested on a representative group of eight betabaculoviruses with comparisons of melting temperatures to allow for quick and preliminary granulovirus detection. The proposed real-time PCR procedure may be a very useful tool as an easily accessible screening method in a majority of laboratories.
Assuntos
Genoma Viral , Granulovirus/classificação , Reação em Cadeia da Polimerase em Tempo Real/métodos , Proteínas Virais/genética , Animais , Primers do DNA/genética , DNA Viral/genética , Lepidópteros/virologia , Fases de Leitura Aberta , Análise de Sequência de DNA , Temperatura de TransiçãoRESUMO
The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is an important maize pest. Due to the environmental impact and emergence of resistance caused by chemical pesticides and transgenic events, the use of baculoviruses becomes a safe and useful alternative for its control in integrated pest management strategies. Here we report the identification of a novel isolate of a granulovirus of S. frugiperda native to the central region of Argentina, named SfGV ARG. We observed that larvae infected with SfGV ARG showed a yellowish coloration, swollen body and, in some cases, severe lesions in the last abdominal segments. We confirmed the identity of the isolate by sequencing fragments of the lef-8, lef-9 and granulin genes and by calculating evolutionary distances using the Kimura-2-Parameter model. SfGV ARG DNA restriction pattern allowed to estimate a genome of at least 135 kb.
Assuntos
Granulovirus/classificação , Granulovirus/isolamento & purificação , Spodoptera/virologia , Animais , ArgentinaRESUMO
DNA polymerase (DNApol) is highly conserved in all baculoviruses and plays an essential role in viral DNA replication. Previous results showed that the DNApol of the betabaculovirus Pieris rapae granulovirus (PiraGV) can localize in the nucleus. However, it is not clear how the DNApol is transported into the nucleus. Bioinformatic and GFP localization analysis showed that PiraGV DNApol contains a nuclear localization signal (NLS) at aa 4-25 (LFKRKLDEPPTDHTLVKAIKLS) of the N-terminus that does not match either the classical monopartite or the bipartite NLS consensus sequence. Multiple-point-substitution analysis confirmed that the NLS is required for transport of PiraGV DNApol into the nucleus. We also substituted the NLS of the PiraGV DNApol for that of the alphabaculovirus Spodoptera litura nuclear polyhedrosis virus (SpltNPV) DNApol. A viral growth curve and quantitative real-time PCR revealed that the substitution impaired viral DNA replication and resulted in a reduction in virus production. Together, our results show that PiraGV contains a novel NLS and that the NLS cannot efficiently replace that of SpltNPV DNApol for viral DNA synthesis and virus production.
Assuntos
DNA Polimerase Dirigida por DNA/química , Granulovirus/enzimologia , Sinais de Localização Nuclear , Proteínas Virais/genética , Sequência de Aminoácidos , Animais , Borboletas/virologia , Núcleo Celular/virologia , DNA Viral/genética , DNA Polimerase Dirigida por DNA/genética , DNA Polimerase Dirigida por DNA/metabolismo , Granulovirus/química , Granulovirus/classificação , Granulovirus/genética , Dados de Sequência Molecular , Análise de Sequência de DNA , Proteínas Virais/química , Proteínas Virais/metabolismoRESUMO
Six complete genome sequences of Cydia pomonella granulovirus (CpGV) isolates from Mexico (CpGV-M and CpGV-M1), England (CpGV-E2), Iran (CpGV-I07 and CpGV-I12), and Canada (CpGV-S) were aligned and analyzed for genetic diversity and evolutionary processes. The selected CpGV isolates represented recently identified phylogenetic lineages of CpGV, namely, the genome groups A to E. The genomes ranged from 120,816 bp to 124,269 bp. Several common differences between CpGV-M, -E2, -I07, -I12 and -S to CpGV-M1, the first sequenced and published CpGV isolate, were highlighted. Phylogenetic analysis based on the aligned genome sequences grouped CpGV-M and CpGV-I12 as the most derived lineages, followed by CpGV-E2, CpGV-S and CpGV-I07, which represent the most basal lineages. All of the genomes shared a high degree of co-linearity, with a common setup of 137 (CpGV-I07) to 142 (CpGV-M and -I12) open reading frames with no translocations. An overall trend of increasing genome size and a decrease in GC content was observed, from the most basal lineage (CpGV-I07) to the most derived (CpGV-I12). A total number of 788 positions of single nucleotide polymorphisms (SNPs) were determined and used to create a genome-wide SNP map of CpGV. Of the total amount of SNPs, 534 positions were specific for exactly one of either isolate CpGV-M, -E2, -I07, -I12 or -S, which allowed the SNP-based detection and identification of all known CpGV isolates.
Assuntos
Evolução Molecular , Granulovirus/genética , Mariposas/virologia , Polimorfismo de Nucleotídeo Único , Animais , Sequência de Bases , Canadá , Genoma Viral , Granulovirus/classificação , Granulovirus/isolamento & purificação , Irã (Geográfico) , México , Filogenia , Proteínas Virais/química , Proteínas Virais/genéticaRESUMO
Different isolates of Cydia pomonella granulovirus (CpGV) are used worldwide to control codling moth larvae (Cydia pomonella) in pome fruit production. Two types of dominantly inherited field resistance of C. pomonella to CpGV have been recently identified: Z-chromosomal type I resistance and autosomal type II resistance. In the present study, a CpGV-resistant C. pomonella field population (termed SA-GO) from northeastern Germany was investigated. SA-GO individuals showed cross-resistance to CpGV isolates of genome group A (CpGV-M) and genome group E (CpGV-S), whereas genome group B (CpGV-E2) was still infective. Crossing experiments between individuals of SA-GO and the susceptible C. pomonella strain CpS indicated the presence of a dominant autosomal inheritance factor. By single-pair inbreeding of SA-GO individuals for two generations, the genetically more homogenous strain CpRGO was generated. Resistance testing of CpRGO neonates with different CpGV isolates revealed that isolate CpGV-E2 and isolates CpGV-I07 and -I12 were resistance breaking. When progeny of hybrid crosses and backcrosses between individuals of resistant strain CpRGO and susceptible strain CpS were infected with CpGV-M and CpGV-S, resistance to CpGV-S appeared to be autosomal and dominant for larval survivorship but recessive when success of pupation of the hybrids was considered. Inheritance of resistance to CpGV-M, however, is proposed to be both autosomal and Z linked, since Z linkage of resistance was needed for pupation. Hence, we propose a further type III resistance to CpGV in C. pomonella, which differs from type I and type II resistance in its mode of inheritance and response to CpGV isolates from different genome groups.IMPORTANCE The baculovirus Cydia pomonella granulovirus (CpGV) is registered and applied as a biocontrol agent in nearly all pome fruit-growing countries worldwide to control codling moth caterpillars in an environmentally friendly manner. It is therefore the most widely used commercial baculovirus biocontrol agent. Since 2005, field resistance of codling moth to CpGV products has been observed in more than 40 field plantations in Europe, threatening organic and integrated apple production. Knowledge of the inheritance and mechanism(s) of resistance is indispensable for the understanding of host response to baculovirus infection on the population level and the coevolutionary arms race between virus and host, as well as for the development of appropriate resistance management strategies. Here, we report a codling moth field population with a new type of resistance, which appears to follow a highly complex inheritance in regard to different CpGV isolates.
Assuntos
Granulovirus/genética , Granulovirus/isolamento & purificação , Mariposas/virologia , Animais , Europa (Continente) , Ligação Genética , Granulovirus/classificação , Granulovirus/fisiologia , Padrões de Herança , Larva/imunologia , Larva/virologia , Malus/parasitologia , Mariposas/crescimento & desenvolvimento , Mariposas/imunologia , Doenças das Plantas/parasitologiaRESUMO
The complete genomes of two novel South African betabaculovirus isolates, namely Phthorimaea operculella granulovirus (PhopGV-SA) and Plutella xylostella granulovirus (PlxyGV-SA), were sequenced and compared to the respective reference isolates PhopGV-1346 and PlxyGV-K1. For both isolates, the genome size and guanine-cytosine (GC) content were similar to those of the respective reference genomes. However, numerous-single nucleotide polymorphisms (SNPs) and several insertions/deletions were observed, revealing the novelty of the isolates. Focus was placed on analysing the observed insertion/deletion events by conducting amino acid sequence alignments for all ORFs of each isolate against all respective ORFs in the corresponding reference isolate. Certain ORFs in each granulovirus genome contained significant insertion/deletion events. In addition, the PlxyGV-SA genome had single-nucleotide insertions/deletions in ORFs 38 and 49 that resulted in the extension and complete overlap of these two ORFs with the neighbouring ORFs 39 and 48, respectively. These novel isolates have significant potential for development and application as biopesticides in South Africa, and the genetic variations observed may have important implications for the biological activity and management of host resistance in the field.
Assuntos
DNA Viral/química , DNA Viral/genética , Genoma Viral , Granulovirus/classificação , Granulovirus/genética , Composição de Bases , Variação Genética , Mutação INDEL , Fases de Leitura Aberta , Polimorfismo de Nucleotídeo Único , Alinhamento de Sequência , Análise de Sequência de DNA , África do SulRESUMO
Cnaphalocrocis medinalis is a major pest of rice in South and South-East Asia. Insecticides are the major means farmers use for management. A naturally occurring baculovirus, C. medinalis granulovirus (CnmeGV), has been isolated from the larvae and this has the potential for use as microbial agent. Here, we described the complete genome sequence of CnmeGV and compared it to other baculovirus genomes. The genome of CnmeGV is 112,060 base pairs in length, has a G+C content of 35.2%. It contains 133 putative open reading frames (ORFs) of at least 150 nucleotides. A hundred and one (101) of these ORFs are homologous to other baculovirus genes including 37 baculovirus core genes. Thirty-two (32) ORFs are unique to CnmeGV with no homologues detected in the GeneBank and 53 tandem repeats (TRs) with sequence length from 25 to 551 nt intersperse throughout the genome of CnmeGV. Six (6) homologous regions (hrs) were identified interspersed throughout the genome. Hr2 contains 11 imperfect palindromes and a high content of AT sequence (about 73%). The unique ORF28 contains a coiled-coil region and a zinc finger-like domain of 4-50 residues specialized by two C2C2 zinc finger motifs that putatively bound two atoms of zinc. ORF21 encoding a chit-1 protein suggesting a horizontal gene transfer from alphabaculovirus. The putative protein presents two carbohydrate-binding module family 14 (CBM_14) domains rather than other homologues detected from betabaculovirus that only contains one chit-binding region. Gene synteny maps showed the colinearity of sequenced betabaculovirus. Phylogenetic analysis indicated that CnmeGV grouped in the betabaculovirus, with a close relation to AdorGV. The cladogram obtained in this work grouped the 17 complete GV genomes in one monophyletic clade. CnmeGV represents a new crambidae host-isolated virus species from the genus Betabaculovirus and is most closely relative of AdorGV. The analyses and information derived from this study will provide a better understanding of the pathological symptoms caused by this virus and its potential use as a microbial pesticide.
Assuntos
Genoma Viral , Granulovirus/genética , Mariposas/virologia , Sequência de Aminoácidos , Animais , Baculoviridae/classificação , Baculoviridae/genética , Sequência de Bases , Sequência Conservada , Ordem dos Genes , Genes Virais , Genômica/métodos , Granulovirus/classificação , Granulovirus/isolamento & purificação , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Fases de Leitura Aberta , Filogenia , Alinhamento de Sequência , Sequências de Repetição em Tandem , Transcrição GênicaRESUMO
To date, proteomic studies have been performed on occlusion-derived viruses (ODVs) from five members of the family Baculoviridae, genus Alphabaculovirus, but only a single member of the genus Betabaculovirus (Pieris rapae granulovirus). In this study, LC-MS/MS was used to analyse the ODV proteins of Clostera anachoreta granulovirus (ClanGV), another member of the genus Betabaculovirus. The results indicated that 73 proteins, including the products of 27 baculovirus core genes, were present in ClanGV ODVs. This is the largest number of ODV proteins identified in baculoviruses to date. To the best of our knowledge, 24 of these proteins were newly identified as ODV-associated proteins. Twelve of the proteins were shared by all seven of the other baculoviruses that have been analysed by proteomic techniques, including P49, PIF-2, ODV-EC43, P74, P6.9, P33, VP39, ODV-EC27, VP91, GP41, VLF-1 and VP1054. ClanGV shared between 20 and 36 ODV proteins with each of the other six baculoviruses that have been analysed by proteomics. Ten proteins were identified only as ODV components of ClanGV and PrGV: Clan22, Clan27, Clan69, Clan83, Clan84, Clan90, Clan116, Clan94, FGF-3 and ME53, the first seven of which were encoded by betabaculovirus-specific genes. These findings may provide novel insights into baculovirus structure as well as reveal similarities and differences between alphabaculoviruses and betabaculoviruses.
Assuntos
Granulovirus/química , Vírus de Insetos/química , Vírus de Insetos/genética , Mariposas/virologia , Proteínas Virais/química , Animais , Genoma Viral , Granulovirus/classificação , Granulovirus/genética , Granulovirus/crescimento & desenvolvimento , Vírus de Insetos/classificação , Vírus de Insetos/crescimento & desenvolvimento , Espectrometria de Massas , Dados de Sequência Molecular , Fases de Leitura Aberta , Filogenia , Proteômica , Proteínas Virais/genética , Proteínas Virais/metabolismoRESUMO
The NPP-R1 isolate of CpGV is able to replicate on CpGV-M-resistant codling moths. However, its efficacy is not sufficient to provide acceptable levels of control in natural (orchard) conditions. A laboratory colony derived from resistant codling moths was established, which exhibited a homogeneous genetic background and a resistance level more than 7000 fold. By successive cycles of replication of NPP-R1 in this colony, we observed a progressive increase in efficacy. After 16 cycles (isolate 2016-r16), the efficacy of the virus isolate was equivalent to that of CpGV-M on susceptible insects. This isolate was able to control both CpGV-M-susceptible and CpGV-M-resistant insects with similar efficacy. No reduction in the levels of occlusion body production in susceptible larvae was observed for 2016-r16 compared to CpGV-M.
Assuntos
Granulovirus/fisiologia , Mariposas/imunologia , Mariposas/virologia , Adaptação Fisiológica , Animais , Granulovirus/classificação , Granulovirus/genética , Mariposas/genética , Mariposas/fisiologia , Controle Biológico de VetoresRESUMO
BACKGROUND: Cassava (Manihot esculenta) is the basic source for dietary energy of 500 million people in the world. In Brazil, Erinnyis ello ello (Lepidoptera: Sphingidae) is a major pest of cassava crops and a bottleneck for its production. In the 1980s, a naturally occurring baculovirus was isolated from E. ello larva and successfully applied as a bio-pesticide in the field. Here, we described the structure, the complete genome sequence, and the phylogenetic relationships of the first sphingid-infecting betabaculovirus. RESULTS: The baculovirus isolated from the cassava hornworm cadavers is a betabaculovirus designated Erinnyis ello granulovirus (ErelGV). The 102,759 bp long genome has a G + C content of 38.7%. We found 130 putative ORFs coding for polypeptides of at least 50 amino acid residues. Only eight genes were found to be unique. ErelGV is closely related to ChocGV and PiraGV isolates. We did not find typical homologous regions and cathepsin and chitinase homologous genes are lacked. The presence of he65 and p43 homologous genes suggests horizontal gene transfer from Alphabaculovirus. Moreover, we found a nucleotide metabolism-related gene and two genes that could be acquired probably from Densovirus. CONCLUSIONS: The ErelGV represents a new virus species from the genus Betabaculovirus and is the closest relative of ChocGV. It contains a dUTPase-like, a he65-like, p43-like genes, which are also found in several other alpha- and betabaculovirus genomes, and two Densovirus-related genes. Importantly, recombination events between insect viruses from unrelated families and genera might drive baculovirus genomic evolution.