DNA characterization of eight geographic isolates of granulosis virus from the potato tuber moth (Phthorimaea operculella) (lepidoptera, gelechiidae)

A granulovirus (GV) isolated from Epinotia aporema (Lepidoptera: Tortricidae)-a major soybean pest-was studied in terms of its main morphological, biochemical, and biological properties. The ovoidal occlusion bodies were 466 by 296 nm in size, and their most prominent protein had an apparent molecular mass of 29 kDa. Its amino-terminal sequence was remarkably homologous to that of the granulins of other GVs. The DNA genome size was estimated to be 120 kbp. The high specificity and pathogenicity of this newly described granulovirus (EpapGV) indicate that it is indeed a good candidate for the biological control of this pest.The bean shoot borer, Epinotia aporema (Wals.), is a serious pest of soybean and other legume crops in South America. In Argentina, damages caused by this tortricid decrease soybean yields up to 40%, depending on population level and environmental conditions (18). Currently, broad-spectrum chemical insecticides are used to control this caterpillar, delaying or suppressing field colonization by natural enemies. This scenario compromises the implementation of a proper integrated pest management scheme for soybean crops, in areas where the incidence of E. aporema reaches high population levels (25).Among pathogens, a granulovirus (GV) was detected as the main mortality factor (6, 26). In general, the potential of baculoviruses for pest control has been well documented and they have proven to be effective against many pests (9,15,24). In this regard, preliminary experiments showed that E. aporema GV (EpapGV) could be a safe alternative for inclusion in soybean pest management (25). However, former studies were directed towards evaluating its virulence, and none of the previously cited reports addressed the characterization of the virus. As an initial point in our research, we identified and characterized a GV isolate from E. aporema, indigenous to the main soybean area of Argentina.Virus isolation and multiplication. A colony of E. aporema caterpillars reared on artificial medium (12) was established in our laboratory. EpapGV was isolated from a single E. aporema larva collected in Oliveros (Santa Fe, Argentina). Viral amplification was carried out, allowing fourth-instar larvae to feed on formalin-free artificial diet, superficially contaminated with 4,000 granules per mm 2 . Granules were purified from homogenized larvae by two cycles of centrifugation on continuous 40 to 65% (wt/wt) sucrose gradients at 100,000 ϫ g for 1 h. Virions were released by hydrolyzing granules in 0.1 M Na 2 CO 3 -0.17 M NaCl-0.01 M EDTA (pH 10.5) at 37°C for 30 min. Following the dissolution of the granules, the suspension was neutralized by addition of 1 M HCl, and undissolved material was removed by low-speed centrifugation.Electron microscopy. Tissues were dissected from infected and control larvae, fixed in 3% glutaraldehyde in 0.1 M cacodylate buffer (pH 7.3)-0.25 M sucrose for 3 h, postfixed in 1% osmium tetroxide for 1 h, dehydrated through an ethanolpropylene oxide series, and embedded in Epon-Araldite resin. Ul...

show abstract

“…The restriction patterns of EpapGV DNA were distinct from those published for other GVs (3,4,5,7,11,14,31,33,37,39) (Fig. 2B and C).…”

mentioning

confidence: 49%

“…However, further studies on the viral genome and the comparison of DNA digests from other geographical and temporal isolates of EpapGV will allow us to determine if there are variants of this virus, as previously described for other GV isolates (3,5,32,37). Histopathology.…”

mentioning

confidence: 97%

Characterization of a Granulovirus Isolated from Epinotia aporema Wals. (Lepidoptera: Tortricidae) Larvae

Sciocco-Cap¹,

Parola

Goldberg³

et al. 2001

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…It was soon demonstrated that the virus could be produced in vivo and formulated as dry powder using talc (magnesium silicate), at low costs Wraight et al 2007). Several PhopGV have been isolated from PTM populations around the world and they might vary in virulence and host range (Vickers et al 1991;Zeddam et al 1999). The pathogen proved to be as effective as synthetic insecticides in preventing tuber damage in the field, and under favorable conditions, it persists from one season to another (Reed 1971;Reed and Springett 1971).…”

Section: Introductionmentioning

confidence: 99%

Potential of a granulovirus isolate to control Phthorimaea operculella (Lepidoptera: Gelechiidae)

Mascarin¹,

Alves²,

Rampelotti-Ferreira³

et al. 2010

BioControl

View full text Add to dashboard Cite

In this study a Brazilian granulovirus strain, PhopGV, isolated from the potato tuber moth (PTM) Phthorimaea operculella, was investigated regarding its potential for biological control and in vivo production. The relationship between mortality of P. operculella larvae and virus concentration was determined at different temperatures on potato tubers and susceptibility of P. operculella to PhopGV was also determined on potato leaves. Virulence of PhopGV to P. operculella was not affected by temperatures from 18 to 30°C. The median lethal concentration (LC 50 ) of larvae fed on potato foliage treated with PhopGV was not higher than that verified with larvae fed on treated tubers. Optimal conditions for production of virus-infected larvae were obtained by using the virus suspensions of 41 9 10 5 , 6.3 9 10 5 and 62 9 10 5 OBs ml -1 at 18, 24 and 30°C, which resulted in 32.0, 31.4 and 34.8% of infected larvae collected, respectively. The maximum percentage of infected larvae recovered from tubers was not affected by temperature. However, time for production of virusinfected larvae was longer at 18°C and shorter at 30°C. Persistence of PhopGV was determined on stored tubers and we observed that the virus remained effective for at least two months, causing up to 84.2% mortality of P. operculella at 1 9 10 7 OBs ml -1 . The pathogen was also highly virulent to tomato pinworm, Tuta absoluta, inflicting high percentage of mortality, delaying larval growth and inhibiting pupation. This Brazilian PhopGV strain has potential to control PTM larvae on potato tubers at a broad range of temperature and can be produced in vivo using virus-treated tubers.

show abstract

“…In the following years, various isolates were described around the world, in all potato production areas where P. operculella is found (14,33). These granulovirus isolates appeared to be genetically related (32) and were thus collectively called the Phthorimaea operculella granulovirus (PhopGV). PhopGV isolates were found to efficiently control and prevent potato tuber moth proliferation in storage conditions, without inducing any harm to other beneficial organisms.…”

mentioning

confidence: 99%

Genetic and Biological Analysis of ColombianPhthorimaea operculellaGranulovirus Isolated fromTecia solanivora(Lepidoptera: Gelechiidae)

Espinel

Léry

Villamizar

et al. 2010

Appl Environ Microbiol

View full text Add to dashboard Cite

Tecia solanivora (Lepidoptera: Gelechiidae) is an invasive potato pest of the north of South America that recently colonized zones where Phthorimaea operculella (Lepidoptera: Gelechiidae), a taxonomically related insect, was established. Nowadays, both species can be found in most areas in different proportions. The Phthorimaea operculella granulovirus (PhopGV) was found to efficiently control P. operculella and was used as a biopesticide in storage conditions. However, no appropriate biological control methods exist for T. solanivora, and the use of granulovirus isolates would provide a solution. The Colombian Corporation for Agricultural Research (CORPOICA) carried out several T. solanivora larva samplings in Colombia with the aim of finding potential isolates. Five geographical granulovirus isolates from T. solanivora (VG001, VG002, VG003, VG004, and VG005) were found, and molecular analysis by REN profiles shows three different genotypic variants in Colombia. Analysis of their genomes revealed their relatedness to PhopGV. Two isolates exhibited submolar bands in their REN patterns, suggesting a mixture of viral genotypes. These data were confirmed by PCR amplification and sequencing of particular regions of the viral genomes. Their biological activity was assayed on both hosts, T. solanivora and P. operculella. A significantly higher pathogenicity in both hosts was observed with isolates VG001 and VG005 than with isolate VG003 or a Peruvian isolate (from P. operculella) used as a reference in the bioassay. Based on their molecular and biological activity characteristics, VG001 and VG005 isolates should be selected for further analysis in order to establish their potential as biological control agents.

show abstract

DNA characterization of eight geographic isolates of granulosis virus from the potato tuber moth (Phthorimaea operculella) (lepidoptera, gelechiidae)

Cited by 40 publications

References 20 publications

Characterization of a Granulovirus Isolated from Epinotia aporema Wals. (Lepidoptera: Tortricidae) Larvae

Characterization of a Granulovirus Isolated from Epinotia aporema Wals. (Lepidoptera: Tortricidae) Larvae

Potential of a granulovirus isolate to control Phthorimaea operculella (Lepidoptera: Gelechiidae)

Genetic and Biological Analysis of ColombianPhthorimaea operculellaGranulovirus Isolated fromTecia solanivora(Lepidoptera: Gelechiidae)

Contact Info

Product

Resources

About