Next Article in Journal
Recent Progress in Studies of Porcine Reproductive and Respiratory Syndrome Virus 1 in China
Next Article in Special Issue
Comprehensive Comparison of Baculoviral and Plasmid Gene Delivery in Mammalian Cells
Previous Article in Journal
Four Novel Caudoviricetes Bacteriophages Isolated from Baltic Sea Water Infect Colonizers of Aurelia aurita
Previous Article in Special Issue
The History of Baculovirology in Africa
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Viruses
Volume 15
Issue 7
10.3390/v15071526
viruses-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Insecticidal Traits of Variants in a Genotypically Diverse Natural Isolate of Anticarsia Gemmatalis Multiple Nucleopolyhedrovirus (AgMNPV)

by
Ana Parras-Jurado
1,2,
Delia Muñoz
1,
Inés Beperet
2,
Trevor Williams
3 and
Primitivo Caballero
1,2,*
1
Institute for Multidisciplinary Research in Applied Biology, Universidad Pública de Navarra, 31006 Pamplona, Spain
2
Departamento de Investigación y Desarrollo, Bioinsectis SL, Polígono Industrial Mocholi Plaza Cein 5, Nave A14, 31110 Noáin, Spain
3
Instituto de Ecología AC (INECOL), Xalapa 91073, Veracruz, Mexico
*
Author to whom correspondence should be addressed.
Viruses 2023, 15(7), 1526; https://doi.org/10.3390/v15071526
Submission received: 14 June 2023 / Revised: 4 July 2023 / Accepted: 8 July 2023 / Published: 10 July 2023
(This article belongs to the Special Issue Applications of Baculoviruses: Expression Factories, Vaccines and VLPs, Gene Delivery Vectors, Biological Control and Virus Genetics Models)
Browse Figures
Versions Notes

Abstract

:
Outbreaks of Anticarsia gemmatalis (Hübner, 1818) (Lepidoptera: Erebidae), a major pest of soybean, can be controlled below economic thresholds with methods that do not involve the application of synthetic insecticides. Formulations based on natural isolates of the Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) (Baculoviridae: Alphabaculovirus) played a significant role in integrated pest management programs in the early 2000s, but a new generation of chemical insecticides and transgenic soybean have displaced AgMNPV-based products over the past decade. However, the marked genotypic variability present among and within alphabaculovirus isolates suggests that highly insecticidal genotypic variants can be isolated and used to reduce virus production costs or overcome isolate-dependent host resistance. This study aimed to select novel variants of AgMNPV with suitable insecticidal traits that could complement the existing AgMNPV active ingredients. Three distinct AgMNPV isolates were compared using their restriction endonuclease profile and in terms of their occlusion body (OB) pathogenicity. One isolate was selected (AgABB51) from which eighteen genotypic variants were plaque purified and characterized in terms of their insecticidal properties. The five most pathogenic variants varied in OB pathogenicity, although none of them was faster-killing or had higher OB production characteristics than the wild-type isolate. We conclude that the AgABB51 wild-type isolates appear to be genotypically structured for fast speed of kill and high OB production, both of which would favor horizontal transmission. Interactions among the component variants are likely to influence this insecticidal phenotype.

1. Introduction

The velvetbean caterpillar, Anticarsia gemmatalis (Hübner, 1818) (Lepidoptera: Erebidae), is one of the main species of the soybean pest complex. It causes major economic damage to this crop across the Americas [1,2,3,4]. The main strategies employed to control A. gemmatalis outbreaks rely on the use of synthetic insecticides, a range of selective or biorational products and the cultivation of transgenic plants expressing Bt insecticidal proteins [5,6,7,8].
The Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) (Baculoviridae: Alphabaculovirus), a natural pathogen of this pest, has played a significant role in integrated pest control programs, and was applied to over ~2 million hectares annually in the early 2000s. The high pathogenicity of the virus results in the control of this pest below economic thresholds following a single application of virus occlusion bodies (OBs) to soybean crops [9]. However, the use of AgMNPV-based insecticides has been drastically reduced over the past decade due to the widespread adoption of transgenic soybean [10,11,12].
One of the key steps in the development of virus-based insecticides is the selection of the active material. This is usually achieved by comparing the insecticidal traits of different natural isolates against a target pest population [13,14]. In nature, nucleopolyhedroviruses exist as heterogeneous populations composed of different genotypes [15,16]. Genotypic variants arise from random molecular events involving recombination, insertion, duplication, and the deletion of genomic sequences or horizontal gene transfer [17,18]. Some of these variations confer distinct insecticidal properties, usually measured in terms of OB pathogenicity metrics, speed of kill, and OB production, which can directly influence virus survival and transmission between susceptible hosts [14,19,20,21,22]. Indeed, nucleopolyhedrovirus isolates comprising variants with divergent insecticidal traits have been identified in several lepidopteran host species, including Spodoptera exigua [23], S. frugiperda [24,25], and Helicoverpa armigera [26].
Furthermore, intraspecific genotypic diversity and phenotypic variation has been described among geographical isolates of a wide array of alphabaculovirus species [14,22,27,28]. Characterization of the genotypic variants present in a wild-type isolate has proved to be important for the selection and development of some of these variants as the active ingredients of virus-based insecticides [29,30,31].
Indeed, the prototype AgMNPV-2D, a majority variant present in AgMNPV formulations against A. gemmatalis [32], was originally identified by plaque purification of a wild-type isolate from Brazil [33,34]. However, from field experiences in other host–virus systems [35,36,37], access to a range of highly insecticidal genotypic variants is important in case of isolate-dependent host resistance [38,39,40,41]. Variants can also differ in their OB production traits, which lend some variants to be more amenable than others to mass-production processes necessary for the commercialization of virus insecticides [42].
In this study, we compared several natural isolates of AgMNPV and characterized the genotypic variants present in the most pathogenic isolate, with the aim of comparing the insecticidal traits of the individual variants as potential active substances for novel AgMNPV-based formulations. Specifically, comparative molecular and biological analyses of three AgMNPV isolates resulted in the selection of one of them, from which eighteen genotypic variants were obtained and characterized in terms of OB pathogenicity, speed of kill, and OB productivity.

2. Materials and Methods

2.1. Insects, Cells, and Virus Isolates

The Anticarsia gemmatalis population was established from larvae collected in soybean fields of Tamaulipas, Mexico and maintained at 25 ± 1 °C, 75% relative humidity and 16 h light: 8 h dark photoperiod on a wheatgerm-based semisynthetic diet [43].
Sf9 cells (Gibco, Thermo Fisher Scientific Inc., Waltham, MA, USA) were maintained in Sf-900 II medium (Gibco) at 28 °C.
The Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) isolates used in this study were AgMNPV-30WT (hereinafter known as Ag30WT) isolated in Mexico [22], and AgMNPV-ABB15 (AgABB15) and AgMNPV-ABB51 (AgABB51), which both originated from the virus collection of the Institut National de la Recherche Agronomique (INRA), France and were kindly provided by Miguel López-Ferber. These INRA isolates were likely to have been deposited during the studies on AgMNPV by Crozier and Ribeiro [18]. OBs were amplified in fourth instars of A. gemmatalis and purified via homogenization of each virus-killed larva in 1 mL of 0.1% sodium dodecyl sulfate (SDS) followed by filtration through muslin and centrifugation at 2400× g for 5 min to eliminate insect debris. The resulting pellets were washed and resuspended in 2 vol. milli-Q water. Purified OB suspensions were titrated under phase-contrast microscopy at ×400 using an improved hemocytometer (Paul Marienfeld GmbH, Lauda-Königshofen, Germany) and aliquots of each isolate were stored at −20 °C until required.
Unless otherwise stated, all bioassays and related procedures described in the following sections were performed at 25 °C, 75% relative humidity, 16 h light: 8 h dark photoperiod.

2.2. DNA Extraction from OBs

Occlusion derived virions (ODVs) were released by incubating 40 µL of OB suspension (1010 OBs/mL) with 100 µL of 0.5 M Na2CO3 and 360 µL distilled water at 60 °C for 30 min. A supernatant containing the released virions was obtained via centrifugation at 5900× g for 5 min and immediately transferred to a new microcentrifuge tube and incubated with 25 µL 10% SDS, 25 µL 0.5 M EDTA, and 15 µL proteinase K (20 mg/mL) at 65 °C for 1 h to degrade the virion membrane and the nucleocapsid and, hence, release the virus genome. Viral DNA was then separated from proteins by adding 150 µL MPC Protein Precipitation Reagent (Epicentre, Illumina Inc., San Diego, CA, USA), vortexing vigorously for 10 s, and pelleting the debris via centrifugation at 10,000× g and 4 °C for 10 min. The supernatant was transferred to a new microcentrifuge tube and DNA was pelleted by adding 1 mL ice-cold absolute ethanol and centrifuged at 16,200× g at 4 °C for 10 min. The pelleted DNA was washed with 500 µL 70% ethanol, resuspended in 50 µL bidistilled water, and incubated at 60 °C for 15 min.

2.3. Cloning of Genotypic Variants

Individual genotypes were obtained from AgABB51 via plaque purification [44]. A concentration of 108 OB/mL was used to inoculate fifth instar A. gemmatalis larvae using the droplet feeding method [45]. At 48 h post infection (hpi), infected larvae were bled and hemolymph containing budded virions was collected and stored at −20 °C. Hemolymph was then passed through a 0.45 µm filter and used to prepare six serial dilutions in Sf-900 II (Gibco) medium with antibiotics. A 200 µL volume from each dilution was used to inoculate 5 × 105 Sf9 cells (Gibco) and, at 10 d post infection (dpi), clearly separated individual plaques containing individual clones were collected with a sterile Pasteur pipette and diluted in 300 µL Sf-900 II medium. Clones were then injected into the hemocoel of A. gemmatalis fifth instar larvae that were individually placed in the wells of a cell culture plate with a semisynthetic diet and incubated at 25 °C until death or pupation.

2.4. Viral DNA Restriction Endonuclease Analysis

For restriction endonuclease analysis, 2 µg viral DNA was digested using two units of HindIII (Fast Digest, Thermofisher, Waltham, MA, USA) for 2 h at 37 °C. DNA fragments were separated via electrophoresis in a 1% agarose gel immersed in TAE buffer (40 mM Tris, 20 mM acetic acid, and 1 mM EDTA pH 8.0) running at 18 V for 15 h. DNA fragments were stained using GelRed (Biotium, Fremont, CA, USA) and photographed on a transilluminator (Gel Doc EZ Imager, Bio-Rad Inc., Hercules, CA, USA).

2.5. Biological Activity

The three isolates employed, Ag30WT, AgABB15, and AgABB51, were used to inoculate groups of 28 newly molted second instar larvae of A. gemmatalis at three different concentrations (103, 105, and 107 OBs/mL) using the droplet feeding method [45]. Larvae that drank the OB suspensions within 10 min were individualized in wells of a cell culture plate with a piece of semisynthetic diet. Control larvae drank a solution that contained no OBs. These assays were performed in triplicate using different insect batches. Mortality was recorded every 24 h until all larvae were dead or had pupated.
The pathogenicity of AgABB51 OBs, expressed as the median lethal concentration (LC50), was determined by the droplet feeding method [45]. Groups of 28 newly molted second instar larvae were allowed to drink OB suspensions of one of the following concentrations, expected to cause between 10% and 90% mortality: 1.2 × 103, 3.7 × 103, 1.1 × 104, 3.3 × 104, and 1.0 × 105 OBs/mL. Control larvae drank a solution that contained no OBs. Larvae that drank the OB suspensions within 10 min were individualized in wells of a cell culture plate with semi-synthetic diet and mortality was recorded at 24-h intervals until all larvae had died or pupated. This assay was performed in triplicate with different insect batches. Concentration–mortality data were analyzed via Probit regression to estimate LC50 values using the software POLO Plus (Leora) [46].
Median time to death (MTD) was estimated in AgABB51-infected second instars that consumed a suspension of 6.8 × 104 OBs/mL (estimated to result in ~90% mortality). Larvae that drank the inoculum within 10 min were individualized with a semisynthetic diet and mortality was recorded every 8 h until all larvae had died or pupated. Control larvae consumed a solution without OBs. The study was performed on three batches of insects. In order to estimate MTD values, a survival analysis was performed using the ‘Survival’ package [47] in R (v4.2.2) [48]. The Akaike Information Criterion (AIC) was calculated in order to identify the best fitting model.
OB production was determined in fifth instars inoculated with an LC99 (108 OBs/mL) concentration of AgABB51 OBs using the droplet feeding method [45]. In each of the three biological replicates, dead larvae were collected individually in a 1.5 mL microcentrifuge tube and OBs were purified in a total volume of 1 mL with milli-Q water. OB suspensions from 26 larvae from each replicate were titered in a Neubauer hemocytometer. Data were subjected to a Shapiro–Wilk normality test and analysis of variance (ANOVA) followed by a post hoc Tukey’s HSD test in R (v4.2.2) [48].
An inoculum concentration equal to the LC50 of AgABB51 OBs (1.1 × 104 OBs/mL) was used to evaluate the mortality response of A. gemmatalis second instar larvae to each of the genotypic variants isolated in Section 2.3. Larvae were inoculated using the droplet feeding method [45] and incubated individually on a semisynthetic diet in the wells of a cell culture plate. Mortality was registered daily until all individuals were dead or pupated. The bioassay was performed on three batches of insects with appropriate controls. Percentage of mortality values were analyzed using one-way ANOVA followed by a post hoc Tukey’s HSD test in SPSS v25.0 software [49].

2.6. Genotypic Variant Selection and Biological Characterization

The genotypic variants that induced higher mortality responses than the wild-type isolate (AgABB51) were selected for further characterization in terms of LC50, MTD, and OB production as described in Section 2.5, whereas MTD values were subjected to a log-rank test using the package ‘Survival’ [47] and a post hoc Bonferroni-corrected pairwise t-test. OB production data were subjected to a Shapiro–Wilk normality test and one-way ANOVA followed by a post hoc Tukey’s HSD test. All analyses were performed using R (v4.2.2) [48].

3. Results

3.1. Identification of AgMNPV Isolates Using Restriction Endonuclease Analysis

Analysis of the genomic DNA of three different AgMNPV isolates (Ag30WT, AgABB15 and AgABB51) revealed three slightly different REN profiles, as judged by the distinct restriction fragment length polymorphisms (Figure 1). All the isolates appeared to generate restriction fragments in submolar concentrations, indicating the presence of different genotypic variants within each isolate (Figure 1).

3.2. Mortality Response to AgMNPV Isolates

Similar mortality values were observed at the lowest and highest viral concentrations used for the three candidate isolates, but isolate AgABB51 resulted in higher larval mortality at 105 OBs/mL (Table 1). Thus, we selected AgABB51 for further characterization.

3.3. Biological and Genotypic Characterization of AgABB51

The pathogenicity of AgABB51 OBs, in terms of the LC50, was estimated at 1.1 × 104 OBs/mL. A median time to death value of 138.6 h post inoculum (hpi) was estimated through a survival analysis using the log-normal model, which was identified as the best fitting model via comparison of distribution-dependent AIC values. The mean OB yield was 1.23 × 109 OBs in A. gemmatalis fifth instars (Table 2).
A total of 128 different clones were obtained from the plaque assay and were each amplified by injection into A. gemmatalis fifth instar larvae. OBs from virus-killed larvae were collected and the viral DNA were digested using HindIII to determine differences in their genomic profile. Eighteen different genotypic variants were obtained and named A to R (Figure 2).
The frequency of each variant was determined as the number of times each characteristic restriction profile was observed in the 128 clones (Figure 3).

3.4. Biological Characterization of AgABB51 Genotypic Variants

The mean percentage of mortality in larvae inoculated with each of the different genotypic variants and the wild-type AgABB51 varied significantly (F18,38 = 12.64; p < 0.001) (Figure 4). However, larvae inoculated with genotypic variants A, B, C, D, E, F, J, I, L, M, N, O, P, and Q showed mortalities as high as those inoculated with AgABB51 OBs in the initial bioassays, at the concentration equal to the LC50 of AgABB51 (1.1 × 104 OBs/mL). Five of these variants were selected for further characterization based on the high mortality values in this preliminary assay (Table 3).
The pathogenicity of AgABB51 and the five selected genotypic variants ranged from 1 × 104 OBs/mL (AgABB51) to 7.6 × 103 OBs/mL (variant I); there were no significant differences detected among these values (Table 3).
Survival analysis using the log-normal model revealed MTD values that varied between 155.0 h (variant E) and 138.9 h (variant M), compared to 139.0 h for the reference AgABB51 isolate (log-rank χ2 = 16.3, d.f. = 5, p < 0.05). However, a post hoc Bonferroni analysis revealed that only the MTD values of AgABB51 and variant M differed significantly compared to variant E, whereas the other variants showed intermediate MTD values (Figure 5a).
In terms of OB production, none of the selected genotypic variants were more productive than the AgABB51 isolate and larvae infected by the variants D, E, I, and L produced fewer OBs than those infected by the AgABB51 isolate (F5,121 = 8.533; p < 0.001) (Figure 5b).

4. Discussion

Three field-collected AgMNPV isolates were compared in terms of restriction endonuclease profile characteristics and their respective insecticidal properties. AgABB51 was recognized as the most genotypically diverse, as judged by the greater number of RFLPs and submolar fragments within its restriction profile, suggesting the presence of more than one genotypic variant in the wild-type isolate. The A. gemmatalis mortality response induced by these isolates was tested at three different concentrations. Similar mortality values were observed at the lowest and highest viral concentrations, although AgABB51 resulted in the highest mortality response (87%) at an intermediate inoculum concentration (Table 1). AgABB51 was, therefore, selected for further biological and genotypic characterization. The OB pathogenicity (LC50) and speed-of-kill (MTD) values of this isolate were 1.1 × 104 OBs/mL and 138.6 h in second instars, respectively, whereas OB production averaged 1.23 × 109 OBs in each virus-killed fifth instar (Table 2). Although the AgMNPV-2D variant was not included in our bioassays and comparisons of the results of different experimental events tend to be difficult, the AgABB51 LC50 and MTD values seemed lower than those of AgMNPV-2D, suggesting that AgABB51 might possess traits that would favor its use as a biological insecticide [22,32,50,51].
A total of 128 clones were obtained via plaque purification of the AgABB51 isolate. From these, 18 different genotypic variants (AgABB51-A to R) were identified based on their HindIII restriction profiles (Figure 2). A similar heterogeneity has been reported in the population structure of other alphabaculoviruses [21,52,53], including other AgMNPV isolates [18,22,34,54].
Minor variation in the genome sequence can have a direct impact on the insecticidal phenotype of genotypic variants [42,55,56]. In line with this idea, four of the AgABB51 variants caused a mortality lower than that of AgABB51-wt, whereas 14 variants caused similar mortality to that of the wild-type isolate, including the five selected variants D, E, I, L, and M.
There was no clear correlation between the frequency of the variant in the isolate (Figure 3) and virus-induced mortality (Figure 4), as previously observed by other authors [21,22,56,57]. One reason may be that variants that are amenable to cell culture conditions are not necessarily the most pathogenic or transmissible variants in nature [27,57,58,59]. The alternative in vivo cloning method was originally developed to purify variants from alphabaculovirus isolates [60,61], but is a highly labor-intensive method that has largely been abandoned in favor of plaque purification [21].
The five selected variants from AgABB51 were not significantly more pathogenic than the AgABB51-wt (Table 3). None of these variants displayed a faster speed of kill or higher OB production than AgABB51-wt (Figure 4). Indeed, for most of these variants slower speed of kill was associated with lower OB production per larva, which deviates from the finding that speed of kill is often negatively correlated with OB production, presumably because the virus has more time to replicate and the insect can continue to grow during the infection period [62,63,64]. It appears, therefore, that the AgABB51 isolate is genotypically structured so that the speed of kill favors rapid insect-to-insect transmission in combination with high OB production which also increases the probability of horizontal transmission. These emergent traits likely arise from interactions among the component genotypes, a phenomenon also observed in experiments involving the production of variant mixtures in other alphabaculoviruses [65].
On a more general note, the study of the highly diverse AgABB51 population also highlights the importance of collective infectious units in virus transmission [15,66,67]. The polyploid nature of viruses that disperse in groups, such as alphabaculoviruses, has important consequences for viral evolution, as it increases the probability of coinfection, recombination, and complementation among coinfecting variants. Cells infected with multiple virus genomes will favor interactions between viruses, that may result in changes in viral pathogenesis, the diversity of the virus progeny, and the evolution of host resistance [67].

5. Conclusions

Plaque purification and restriction endonuclease analysis revealed that a natural isolate of AgMNPV, named AgABB51, comprised 18 genotypically distinct variants that differed in OB pathogenicity. Five variants that elicited a high mortality response were selected for further characterization. The lethal concentration metrics and speed of kill of the variants were generally similar to that of the natural isolate, whereas OB production was generally lower than observed in the natural isolate. Future studies should examine the role of interactions among the component genotypes that are likely to affect the insecticidal phenotype of the virus and its efficacy as a biological pesticide.

Author Contributions

Conceptualization, P.C.; formal analysis, A.P.-J.; funding acquisition, P.C.; investigation, A.P.-J.; resources, T.W.; methodology, A.P.-J., I.B. and P.C.; writing—original draft preparation, A.P.-J.; writing—review and editing, A.P.-J., D.M., T.W. and P.C. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Ministerio de Ciencia e Innovacion, grant number AGL2017-83498-C2-1-R. A.P.-J. received a predoctoral grant PRE2018-086829 from the Agencia Estatal de Investigación (Ministerio de Ciencia e Innovación) of the Spanish Government.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data presented in this study are available on request from the corresponding author.

Acknowledgments

We thank Miguel López-Ferber for providing two of the AgMNPV isolates and Noelia Gorría and Itxaso Ibáñez for insect rearing. J. Sebastián Gómez Díaz (INECOL) provided logistical support to T.W.

Conflicts of Interest

The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

References

  1. Bueno, R.C.O.; de Bueno, A.F.; Moscardi, F.; Postali Parra, J.R.; Hoffmann-Campo, C.B. Lepidopteran Larva Consumption of Soybean Foliage: Basis for Developing Multiple-Species Economic Thresholds for Pest Management Decisions. Pest Manag. Sci. 2011, 67, 170–174. [Google Scholar] [CrossRef] [Green Version]
  2. Moscardi, F.; de Carvalho, R.C.Z. Consumo e utilização de folhas da soja por Anticarsia gemmatalis Hüb. (Lepidoptera: Noctuidae) infectada, em diferentes estádios larvais, por seu vírus de poliedrose nuclear. An.-Soc. Entomol. Bras. 1993, 22, 267–280. [Google Scholar] [CrossRef]
  3. Bayer Crop Science Bayer-Crop Pests Compendium-Anticarsia Gemmatalis by Bayer Crop Science AG. Available online: https://www.agriculture-xprt.com/products/bayer-anticarsia-gemmatalis-617566 (accessed on 24 May 2023).
  4. Musser, F.R.; Catchot, A.L.; Conley, S.P.; Davis, J.A.; Difonzo, C.; Greene, J.K.; Lorenz, G.M.; Owens, D.; Reisig, D.D.; Roberts, P.; et al. 2019 Soybean Insect Losses in the United States. Midsouth Entomol. 2020, 13, 1–23. [Google Scholar]
  5. Fernandes, F.O.; Abreu, J.Á.D.; Christ, L.M.; Rosa, A.P.S.A. Da Insecticides Management Used in Soybean for the Control of Anticarsia gemmatalis (Hübner, 1818) (Lepidoptera: Eribidae). J. Agric. Sci. 2018, 10, 223. [Google Scholar] [CrossRef] [Green Version]
  6. Degrande, P.E.; Vivan, L.M. Pragas Da Soja. Tecnologia e Produção: Soja e Milho 2011/2012; Fundação MT: Rondonópolis, Brazil, 2012; pp. 155–206. [Google Scholar]
  7. Murúa, M.G.; Vera, M.A.; Herrero, M.I.; Fogliata, S.V.; Michel, A. Defoliation of Soybean Expressing Cry1Ac by Lepidopteran Pests. Insects 2018, 9, 4–8. [Google Scholar] [CrossRef] [Green Version]
  8. Bueno, R.C.O.F.; Raetano, C.G.; Junior, J.D.; Carvalho, F.K. Integrated Management of Soybean Pests: The Example of Brazil. Outlooks Pest Manag. 2017, 28, 149–153. [Google Scholar] [CrossRef]
  9. Moscardi, F. Assessment of the Application of Baculoviruses for Control of Lepidoptera. Annu. Rev. Entomol. 1999, 44, 257–289. [Google Scholar] [CrossRef]
  10. Sosa-Gómez, D.R. Microbial Control of Soybean Pest Insects and Mites. In Microbial Control of Insect and Mite Pests: From Theory to Practice; Elsevier Inc.: Londrina, Brazil, 2017; pp. 199–208. ISBN 978-0-12-803566-5. [Google Scholar]
  11. Moscardi, F.; de Souza, M.L.; de Castro, M.E.B.; Lara Moscardi, M.; Szewczyk, B. Baculovirus Pesticides: Present State and Future Perspectives. In Microbes and Microbial Technology; Ahmad, I., Ahmad, F., Pichtel, J., Eds.; Springer: New York, NY, USA, 2011; pp. 415–445. ISBN 978-1-4419-7930-8. [Google Scholar]
  12. Valicente, F.H. Entomopathogenic Viruses. In Natural Enemies of Insect Pests in Neotropical Agroecosystems; Souza, B., Vázquez, L.L., Marucci, R.C., Eds.; Springer: Cham, Switzerland, 2019; pp. 137–150. ISBN 978-3-030-24733-1. [Google Scholar]
  13. Popham, H.J.R.; Rowley, D.L.; Harrison, R.L. Differential Insecticidal Properties of Spodoptera frugiperda multiple nucleopolyhedrovirus Isolates against Corn-Strain and Rice-Strain Fall Armyworm, and Genomic Analysis of Three Isolates. J. Invertebr. Pathol. 2021, 183, 107561. [Google Scholar] [CrossRef]
  14. Rowley, D.L.; Popham, H.J.R.; Harrison, R.L. Genetic Variation and Virulence of Nucleopolyhedroviruses Isolated Worldwide from the Heliothine Pests Helicoverpa armigera, Helicoverpa zea, and Heliothis virescens. J. Invertebr. Pathol. 2011, 107, 112–126. [Google Scholar] [CrossRef]
  15. Clavijo, G.; Williams, T.; Muñoz, D.; Caballero, P.; López-Ferber, M. Mixed Genotype Transmission Bodies and Virions Contribute to the Maintenance of Diversity in an Insect Virus. Proc. Biol. Sci. 2010, 277, 943–951. [Google Scholar] [CrossRef]
  16. Erlandson, M.A. Genetic Variation in Field Populations of Baculoviruses: Mechanisms for Generating Variation and Its Potential Role in Baculovirus Epizootiology. Virol. Sin. 2009, 24, 458–469. [Google Scholar] [CrossRef]
  17. de Brito, A.F.; Braconi, C.T.; Weidmann, M.; Dilcher, M.; Pereira Alves, J.M.; Gruber, A.; de Andrade Zanotto, P.M. The Pangenome of the Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV). Genome Biol. Evol. 2016, 8, 94–108. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  18. Croizier, G.; Ribeiro, H.C.T. Recombination as a Possible Major Cause of Genetic Heterogeneity in Anticarsia gemmatalis nuclear polyhedrosis virus Wild Populations. Virus Res. 1992, 26, 183–196. [Google Scholar] [CrossRef]
  19. Cabodevilla, O.; Ibañez, I.; Simón, O.; Murillo, R.; Caballero, P.; Williams, T. Occlusion Body Pathogenicity, Virulence and Productivity Traits Vary with Transmission Strategy in a Nucleopolyhedrovirus. Biol. Control 2011, 56, 184–192. [Google Scholar] [CrossRef]
  20. Harrison, R.L.; Puttler, B.; Popham, H.J.R. Genomic Sequence Analysis of a Fast-Killing Isolate of Spodoptera frugiperda multiple nucleopolyhedrovirus. J. Gen. Virol. 2008, 89, 775–790. [Google Scholar] [CrossRef]
  21. Aguirre, E.; Beperet, I.; Williams, T.; Caballero, P. Genetic Variability of Chrysodeixis includens nucleopolyhedrovirus (ChinNPV) and the Insecticidal Characteristics of Selected Genotypic Variants. Viruses 2019, 11, 581. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  22. Del-Angel, C.; Lasa, R.; Rodríguez-del-Bosque, L.A.; Mercado, G.; Beperet, I.; Caballero, P.; Williams, T. Anticarsia gemmatalis nucleopolyhedrovirus from Soybean Crops in Tamaulipas, Mexico: Diversity and Insecticidal Characteristics of Individual Variants and Their Co-Occluded Mixtures. Fla. Entomol. 2018, 101, 404–410. [Google Scholar] [CrossRef]
  23. Smits, P.H.; Vlak, J.M. Registration of the First Viral Insecticide in the Netherlands: The Development of SPOD-X, Based on Spodoptera exigua nuclear polyhedrosis virus. Meded. Van De Fac. Landbouwwet. Rijksuniv. Gent 1994, 59, 385–392. [Google Scholar]
  24. Niz, J.M.; Salvador, R.; Ferrelli, M.L.; de Cap, A.S.; Romanowski, V.; Berretta, M.F. Genetic Variants in Argentinean Isolates of Spodoptera frugiperda multiple nucleopolyhedrovirus. Virus Genes 2020, 56, 401–405. [Google Scholar] [CrossRef]
  25. Masson, T.; Fabre, M.L.; Pidre, M.L.; Niz, J.M.; Berretta, M.F.; Romanowski, V.; Ferrelli, M.L. Genomic Diversity in a Population of Spodoptera frugiperda nucleopolyhedrovirus. Infect. Genet. Evol. 2021, 90, 104749. [Google Scholar] [CrossRef]
  26. Baillie, V.L.; Bouwer, G. High Levels of Genetic Variation within Helicoverpa armigera nucleopolyhedrovirus Populations in Individual Host Insects. Arch. Virol. 2012, 157, 2281–2289. [Google Scholar] [CrossRef] [PubMed]
  27. Cory, J.S.; Green, B.M.; Paul, R.K.; Hunter-Fujita, F. Genotypic and Phenotypic Diversity of a Baculovirus Population within an Individual Insect Host. J. Invertebr. Pathol. 2005, 89, 101–111. [Google Scholar] [CrossRef] [PubMed]
  28. Lee, H.H.; Miller, L.K. Isolation of Genotypic Variants of Autographa californica nuclear polyhedrosis virus. J. Virol. 1978, 27, 754–767. [Google Scholar] [CrossRef] [Green Version]
  29. Arrizubieta, M.; Simón, O.; Caballero, P.; Williams, T. Nuevos Genotipos Del Nucleopoliedrovirus Simple de Helicoverpa Armigera (HearSNPV), Procedimiento Para Su Producción y Uso Como Agente de Control Biológico. Patent ES2555165, 29 December 2015. [Google Scholar]
  30. Caballero, P.; Bernal, A.; Simón, O.; Carnero, A.; Hernández-Suárez, E.; Williams, T.G. Nuevos Genotipos Del Nucleopoliedrovirus Simple de Chrysodeixis Chalcites (ChchSNPV), Procedimiento Para su Producción y Uso Como Agente de Control Biológico. Patent ES2504866, 8 October 2014. [Google Scholar]
  31. Caballero, P.; Murillo, R.; Muñoz, D.; Williams, T. El Nucleopoliedrovirus de Spodoptera exigua (Lepidoptera: Noctuidae) Como Bioplaguicida: Análisis de Avances Recientes En España. Rev. Colomb Entomol. 2009, 35, 105–115. [Google Scholar] [CrossRef]
  32. Oliveira, J.V.; Wolff, J.L.C.; Garcia-Maruniak, A.; Ribeiro, B.M.; de Castro, M.E.B.; de Souza, M.L.; Moscardi, F.; Maruniak, J.E.; de Andrade Zanotto, P.M. Genome of the Most Widely Used Viral Biopesticide: Anticarsia gemmatalis multiple nucleopolyhedrovirus. J. Gen. Virol. 2006, 87, 3233–3250. [Google Scholar] [CrossRef] [PubMed]
  33. Allen, G.E.; Knell, J.D. A Nuclear Polyhedrosis Virus of Anticarsia gemmatalis: I. Ultrastructure, Replication, and Pathogenicity. Fla. Entomol. 1977, 60, 233. [Google Scholar] [CrossRef]
  34. Maruniak, J.E.; Garcia-Maruniak, A.; Souza, M.L.; Zanotto, P.M.A.; Moscardi, F. Physical Maps and Virulence of Anticarsia gemmatalis nucleopolyhedrovirus Genomic Variants. Arch. Virol. 1999, 144, 1991–2006. [Google Scholar] [CrossRef]
  35. Fan, J.; Jehle, J.A.; Rucker, A.; Nielsen, A.L. First Evidence of CpGV Resistance of Codling Moth in the USA. Insects 2022, 13, 533. [Google Scholar] [CrossRef]
  36. Jehle, J.A.; Schulze-Bopp, S.; Undorf-Spahn, K.; Fritsch, E. Evidence for a Second Type of Resistance against Cydia pomonella granulovirus in Field Populations of Codling Moths. Appl. Environ. Microb. 2016, 83, e02330-16. [Google Scholar] [CrossRef] [Green Version]
  37. Hoover, K.; Washburn, J.O.; Volkman, L.E. Midgut-Based Resistance of Heliothis virescens to Baculovirus Infection Mediated by Phytochemicals in Cotton. J. Insect. Physiol. 2000, 46, 999–1007. [Google Scholar] [CrossRef]
  38. Eberle, K.E.; Asser-Kaiser, S.; Sayed, S.M.; Nguyen, H.T.; Jehle, J.A. Overcoming the Resistance of Codling Moth against Conventional Cydia pomonella granulovirus (CpGV-M) by a New Isolate CpGV-I12. J. Invertebr. Pathol. 2008, 98, 293–298. [Google Scholar] [CrossRef] [PubMed]
  39. Gebhardt, M.M.; Eberle, K.E.; Radtke, P.; Jehle, J.A. Baculovirus Resistance in Codling Moth Is Virus Isolate-Dependent and the Consequence of a Mutation in Viral Gene Pe38. Proc. Natl. Acad. Sci. USA 2014, 111, 15711–15716. [Google Scholar] [CrossRef]
  40. Abot, A.R.; Moscardi, F.; Fuxa, J.R.; Sosa-Gómez, D.R.; Richter, A.R. Development of Resistance By Anticarsia gemmatalis from Brazil and the United States to a Nuclear Polyhedrosis Virus under Laboratory Selection Pressure. Biol. Control. 1996, 7, 126–130. [Google Scholar] [CrossRef]
  41. Levy, S.M.; Falleiros, A.M.F.; Moscardi, F.; Gregório, E.A. Susceptibility/Resistance of Anticarsia gemmatalis Larvae to Its Nucleopolyhedrovirus (AgMNPV): Structural Study of the Peritrophic Membrane. J. Invertebr. Pathol. 2007, 96, 183–186. [Google Scholar] [CrossRef] [PubMed]
  42. Barrera, G.; Williams, T.; Villamizar, L.; Caballero, P.; Simón, O. Deletion Genotypes Reduce Occlusion Body Potency but Increase Occlusion Body Production in a Colombian Spodoptera frugiperda nucleopolyhedrovirus Population. PLoS ONE 2013, 8, e77271. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  43. Greene, G.L.; Leppla, N.C.; Dickerson, W.A. Velvetbean Caterpillar: A Rearing Procedure and Artificial Medium123. J. Econ. Entomol. 1976, 69, 487–488. [Google Scholar] [CrossRef]
  44. King, L.A.; Possee, R.D. The Baculovirus Expression System. A Laboratory Guide; Chapman & Hall: London, UK, 1992; ISBN 0-412-37150-2. [Google Scholar]
  45. Hughes, P.R.; Wood, H.A. In Vivo and in Vitro Bioassay Methods for Baculoviruses. In The Biology of Baculoviruses; Granados, R.R., Federici, B.A., Eds.; CRC Press: Boca Raton, FL, USA, 1986; Volume 2, pp. 1–30. [Google Scholar]
  46. Polo Plus, version 1.0; LeOra Software: Parma, MO, USA, 2003.
  47. Therneau, T.M. A Package for Survival Analysis in R; 2023. Available online: https://CRAN.Rproject.org/package=survival (accessed on 5 April 2023).
  48. R Core Team. R: A Language and Environment for Statistical Computing; R Foundation for Statistical Computing: Vienna, Austria, 2022. [Google Scholar]
  49. IBM SPSS Statistics. IBM SPSS Statistics for Windows, version 25.0; IBM Corp: Armonk, NY, USA, 2017. [Google Scholar]
  50. Ferreira, B.C.; Melo, F.L.; Silva, A.M.R.; Sanches, M.M.; Moscardi, F.; Ribeiro, B.M.; Souza, M.L. Biological and Molecular Characterization of Two Anticarsia gemmatalis multiple nucleopolyhedrovirus Clones Exhibiting Contrasting Virulence. J. Invertebr. Pathol. 2019, 164, 23–31. [Google Scholar] [CrossRef]
  51. da Silveira, E.B.; Cordeiro, B.A.; Ribeiro, B.M.; de Castro, M.E.B.; Soares, E.F.; Báo, S.N. An Anticarsia gemmatalis multiple nucleopolyhedrovirus Mutant, VApAg, Induces Hemocytes Apoptosis in Vivo and Displays Reduced Infectivity in Larvae of Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae). Virus Res. 2007, 130, 182–192. [Google Scholar] [CrossRef] [Green Version]
  52. Corsaro, B.G.; Fraser, M.J. Characterization of Genotypic and Phenotypic Variation in Plaque-Purified Strains of HzSNPV Elkar Isolate. Intervirology 1987, 28, 185–198. [Google Scholar] [CrossRef]
  53. Hodgson, D.J.; Vanbergen, A.J.; Watt, A.D.; Hails, R.S.; Cory, J.S. Phenotypic Variation between Naturally Co-Existing Genotypes of a Lepidopteran Baculovirus. Evol. Ecol. Res. 2001, 3, 687–701. [Google Scholar]
  54. Ribeiro, H.C.T.; Pavan, O.H.O.; Muotri, A.R. Comparative Susceptibility of Two Different Hosts to Genotypic Variants of the Anticarsia gemmatalis nuclear polyhedrosis virus. Entomol. Exp. Appl. 1997, 83, 233–237. [Google Scholar] [CrossRef]
  55. Ogembo, J.G.; Chaeychomsri, S.; Kamiya, K.; Ishikawa, H.; Katou, Y.; Ikeda, M.; Kobayashi, M. Cloning and Comparative Characterization of Nucleopolyhedroviruses Isolated from African Bollworm, Helicoverpa armigera, (Lepidoptera: Noctudiae) in Different Geographic Regions. J. Insect. Biotechnol. Sericol. 2007, 76, 1_39–1_49. [Google Scholar] [CrossRef]
  56. Bernal, A.; Simón, O.; Williams, T.; Muñoz, D.; Caballero, P. A Chrysodeixis chalcites single-nucleocapsid nucleopolyhedrovirus Population from the Canary Islands Is Genotypically Structured To Maximize Survival. Appl. Environ. Microb. 2013, 79, 7709–7718. [Google Scholar] [CrossRef] [Green Version]
  57. Simon, O.; Williams, T.; Lopez-Ferber, M.; Caballero, P. Genetic Structure of a Spodoptera frugiperda nucleopolyhedrovirus Population: High Prevalence of Deletion Genotypes. Appl. Environ. Microb. 2004, 70, 5579–5588. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  58. Pijlman, G.P.; van den Born, E.; Martens, D.E.; Vlak, J.M. Autographa californica baculoviruses with Large Genomic Deletions Are Rapidly Generated in Infected Insect Cells. Virology 2001, 283, 132–138. [Google Scholar] [CrossRef] [Green Version]
  59. Kool, M.; Voncken, J.W.; van Lier, F.L.; Tramper, J.; Vlak, J.M. Detection and Analysis of Autographa californica nuclear polyhedrosis virus Mutants with Defective Interfering Properties. Virology 1991, 183, 739–746. [Google Scholar] [CrossRef]
  60. Smith, I.R.L.; Crook, N.E. In Vivo Isolation of Baculovirus Genotypes. Virology 1988, 166, 240–244. [Google Scholar] [CrossRef]
  61. Muñoz, D.; Castillejo, J.I.; Caballero, P. Naturally Occurring Deletion Mutants Are Parasitic Genotypes in a Wild-Type Nucleopolyhedrovirus Population of Spodoptera exigua. Appl. Environ. Microb. 1998, 64, 4372–4377. [Google Scholar] [CrossRef] [Green Version]
  62. Kumar, C.; Sathiah, N.; Rabindra, R. Optimizing the Time of Harvest of Nucleopolyhedrovirus Infected Spodoptera litura (Fabricius) Larvae under in Vivo Production Systems. Curr. Sci. India 2005, 88, 1682–1684. [Google Scholar]
  63. Cory, J.S.; Myers, J.H. Adaptation in an Insect Host–Plant Pathogen Interaction. Ecol. Lett. 2004, 7, 632–639. [Google Scholar] [CrossRef]
  64. Simón, O.; Williams, T.; López-Ferber, M.; Taulemesse, J.-M.; Caballero, P. Population Genetic Structure Determines Speed of Kill and Occlusion Body Production in Spodoptera frugiperda multiple nucleopolyhedrovirus. Biol. Control. 2008, 44, 321–330. [Google Scholar] [CrossRef]
  65. Williams, T.; López-Ferber, M.; Caballero, P. Nucleopolyhedrovirus Coocclusion Technology: A New Concept in the Development of Biological Insecticides. Front. Microbiol. 2022, 12, 810026. [Google Scholar] [CrossRef] [PubMed]
  66. Sanjuán, R. Collective Infectious Units in Viruses. Trends Microbiol. 2017, 25, 402–412. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  67. Leeks, A.; Sanjuán, R.; West, S.A. The Evolution of Collective Infectious Units in Viruses. Virus Res. 2019, 265, 94–101. [Google Scholar] [CrossRef] [PubMed]
Viruses 15 01526 g001 550
Figure 1. Restriction endonuclease profiles of the genomic DNA of three different AgMNPV isolates following treatment with HindIII. m denotes the molecular marker. Fragment size in kilobases (Kb) is shown on the left. Red arrowheads indicate restriction fragment length polymorphisms (RFLPs) and asterisks on the left of each lane indicate the presence of submolar bands.
Figure 1. Restriction endonuclease profiles of the genomic DNA of three different AgMNPV isolates following treatment with HindIII. m denotes the molecular marker. Fragment size in kilobases (Kb) is shown on the left. Red arrowheads indicate restriction fragment length polymorphisms (RFLPs) and asterisks on the left of each lane indicate the presence of submolar bands.
Viruses 15 01526 g001
Viruses 15 01526 g002 550
Figure 2. HindIII restriction endonuclease profiles of the genomic DNA of each of the 18 different AgABB51 genotypic variants (A to R). m denotes the molecular marker. Fragment size in kilobases (Kb) is shown on the left. The profile of genotype A is used as a reference to identify the presence (red arrowheads) or absence (green arrowheads) of characteristic restriction fragments in the other genotypic variants. Genotype A was selected for this purpose because of its similarity to the wild-type isolate (AgABB51) (shown in Figure 1).
Figure 2. HindIII restriction endonuclease profiles of the genomic DNA of each of the 18 different AgABB51 genotypic variants (A to R). m denotes the molecular marker. Fragment size in kilobases (Kb) is shown on the left. The profile of genotype A is used as a reference to identify the presence (red arrowheads) or absence (green arrowheads) of characteristic restriction fragments in the other genotypic variants. Genotype A was selected for this purpose because of its similarity to the wild-type isolate (AgABB51) (shown in Figure 1).
Viruses 15 01526 g002
Viruses 15 01526 g003 550
Figure 3. Frequency of AgABB51 genotypic variants A through R. The n-value above each column indicates the number of clones exhibiting each variant’s restriction profile out of a total of 128 clones.
Figure 3. Frequency of AgABB51 genotypic variants A through R. The n-value above each column indicates the number of clones exhibiting each variant’s restriction profile out of a total of 128 clones.
Viruses 15 01526 g003
Viruses 15 01526 g004 550
Figure 4. Mean percentage of mortality caused by AgABB51 wild-type isolate and each of the genotypic variants A–R on A. gemmatalis second instars inoculated with 1.1 × 104 OBs/mL. Error bars indicate the standard error. Different lowercase letters indicate significant differences between variants (ANOVA, Tukey HSD; p < 0.05).
Figure 4. Mean percentage of mortality caused by AgABB51 wild-type isolate and each of the genotypic variants A–R on A. gemmatalis second instars inoculated with 1.1 × 104 OBs/mL. Error bars indicate the standard error. Different lowercase letters indicate significant differences between variants (ANOVA, Tukey HSD; p < 0.05).
Viruses 15 01526 g004
Viruses 15 01526 g005 550
Figure 5. (a) Median time to death (MTD) values for the AgABB51 isolate and selected genotypic variants in A. gemmatalis second instars. Error bars indicate standard error and different lowercase letters indicate significant differences between variants (Bonferroni-adjusted t-test; p < 0.05). (b) OB production values obtained for AgABB51 and the selected genotypic variants in A. gemmatalis fifth instars. Error bars indicate standard error and different lowercase letters indicate significant differences between variants (Tukey HSD test; p < 0.05).
Figure 5. (a) Median time to death (MTD) values for the AgABB51 isolate and selected genotypic variants in A. gemmatalis second instars. Error bars indicate standard error and different lowercase letters indicate significant differences between variants (Bonferroni-adjusted t-test; p < 0.05). (b) OB production values obtained for AgABB51 and the selected genotypic variants in A. gemmatalis fifth instars. Error bars indicate standard error and different lowercase letters indicate significant differences between variants (Tukey HSD test; p < 0.05).
Viruses 15 01526 g005
Table
Table 1. Percentage of mortality (± SE) observed for each AgMNPV isolate in A. gemmatalis second instars. Values in parentheses indicate the numbers of larvae tested at each inoculum concentration.
Table 1. Percentage of mortality (± SE) observed for each AgMNPV isolate in A. gemmatalis second instars. Values in parentheses indicate the numbers of larvae tested at each inoculum concentration.
Virus103 OBs/mL105 OBs/mL107 OBs/mL
Ag30WT8 ± 4 (78)58 ± 8 (73)98 ± 2 (83)
AgABB1511 ± 5 (78)72 ± 8 (81)100 ± 0 (79)
AgABB5110 ± 6 (82)87 ± 1 (77)100 ± 0 (74)
None of the control insects (n = 72–78 larvae per isolate) died of polyhedrosis disease.
Table
Table 2. Estimated median lethal concentration (LC50) and median time to death (MTD) values for AgABB51 in A. gemmatalis second instars and OB production values for AgABB51 in A. gemmatalis fifth instars.
Table 2. Estimated median lethal concentration (LC50) and median time to death (MTD) values for AgABB51 in A. gemmatalis second instars and OB production values for AgABB51 in A. gemmatalis fifth instars.
VirusLC50 * (OBs/mL)95% Confidence LimitsMTD (h)95% Confidence LimitsOB Production (OBs/Larva)95% Confidence Limits
LowHighLowHighLowHigh
AgABB511.1 × 1048.5 × 1031.5 × 104138.6134.3143.01.23 × 1091.15 × 1091.31 × 109
* LC50 estimated using Probit regression with a slope (± SE) 1.634 ± 0.148 and intercept (± SE) −6.612 ± 0.612 (goodness-of-fit test χ2 = 0.2198, d.f. = 3, p = 0.974, heterogeneity = 0.0733).
Table
Table 3. Lethal concentration estimates and relative potency values for AgABB51 and selected individual genotypic variants in A. gemmatalis second instars.
Table 3. Lethal concentration estimates and relative potency values for AgABB51 and selected individual genotypic variants in A. gemmatalis second instars.
VariantLC50 (OBs/mL)Relative Potency95% Confidence LimitsLC90 (OBs/mL)Relative Potency95% Confidence LimitsSlope (±SE)
LowHighLowHigh
AgABB511.0 × 104 1--6.9 × 1041--1.54 ± 0.128
D8.8 × 103 1.150.841.565.3 × 1041.300.772.111.64 ± 0.138
E8.0 × 103 1.260.921.724.4 × 1041.550.912.651.72 ± 0.147
I7.6 × 103 1.330.971.814.1 × 1041.681.002.91.75 ± 0.152
L9.2 × 103 1.100.801.505.6 × 1041.210.702.131.62 ± 0.141
M9.2 × 103 1.100.741.364.9 × 1041.400.832.351.65 ± 0.135
Regressions did not differ significantly as hypotheses for parallelism (χ2 = 2.67, df = 5, p > 0.05) and equality (χ2 = 7.83, df = 10, p > 0.05) were not rejected. The relative potencies were calculated as the ratio of effective concentrations relative to the wild-type AgABB51.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Parras-Jurado, A.; Muñoz, D.; Beperet, I.; Williams, T.; Caballero, P. Insecticidal Traits of Variants in a Genotypically Diverse Natural Isolate of Anticarsia Gemmatalis Multiple Nucleopolyhedrovirus (AgMNPV). Viruses 2023, 15, 1526. https://doi.org/10.3390/v15071526

AMA Style

Parras-Jurado A, Muñoz D, Beperet I, Williams T, Caballero P. Insecticidal Traits of Variants in a Genotypically Diverse Natural Isolate of Anticarsia Gemmatalis Multiple Nucleopolyhedrovirus (AgMNPV). Viruses. 2023; 15(7):1526. https://doi.org/10.3390/v15071526

Chicago/Turabian Style

Parras-Jurado, Ana, Delia Muñoz, Inés Beperet, Trevor Williams, and Primitivo Caballero. 2023. "Insecticidal Traits of Variants in a Genotypically Diverse Natural Isolate of Anticarsia Gemmatalis Multiple Nucleopolyhedrovirus (AgMNPV)" Viruses 15, no. 7: 1526. https://doi.org/10.3390/v15071526

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop