Characterization of a new isolate of Malacosoma neustria nucleopolyhedrovirus (ManeNPV) from Turkey

Abstract

IntroductionBaculoviruses are enveloped viruses that have doublestranded, circular DNA genomes ranging in size from 80 to 180 kbp (1,2). Baculoviruses have been isolated from more than 600 insect species belonging to the orders of Lepidoptera, Hymenoptera, Diptera, Orthoptera, Coleoptera, Neuroptera, Thysanura, and Trichoptera (3). The most notable characteristic of baculoviruses is the occlusion body (OB). The occlusion body is a crystalline matrix composed of a protein called polyhedrin, which provides protection to the virions in the environment against proteolytic and chitinolytic enzymes in the decomposing larvae and spreads infection among insects (4,5). Baculoviruses have been taxonomically divided based on their OB morphology into nucleopolyhedroviruses (NPVs) and granuloviruses (GVs), forming polyhedra and granula, respectively (6). In the NPV, the OB ranges in size from 0.4 to 5 µm in diameter and contains several virions (7,8). The OBs of NPVs are most easily seen under light microscope due to their larger size and their light refractory polyhedral structure. The OBs of GVs, called granula, appear as dark granules and are comparatively more difficult to resolve under light microscope. They are ovoid-shaped and about 500 nm long and 20 nm wide (8,9).The family Baculoviridae is divided into 4 genera according to common biological and structural characteristics and patterns of host associations: Alphabaculovirus, which includes lepidopteran-specific baculoviruses and is subdivided into Group I or Group II based on the phylogenetic analysis of the polyhedrin genes from different baculoviruses; Betabaculovirus, comprising lepidopteran-specific granuloviruses; Gammabaculovirus, which includes hymenopteran-specific baculoviruses; and finally Deltabaculovirus, which contains dipteran-specific baculoviruses (4,10,11).Malacosoma neustria (Linnaeus, 1758) (Lepidoptera: Lasiocampidae), known as the European tent caterpillar, is an important defoliator of various fruit trees such as apple, pear, and plum; wild and ornamental trees and shrubs, including oak and rose species, oleaster, sea buckthorn, barberry, elm trees, willow, poplar, and aspen; and birch, particularly in eastern and central Turkey (12)(13)(14). The caterpillars first eat the buds and then leaves of the trees. During some years their population reaches such high numbers that they leave the trees completely leafless. Factors such as weather conditions and natural enemies including predators, parasitoids, and pathogenic microorganisms have historically been important regulatory elements in the population cycles of this insect.The key microbial pathogens of this insect include NPVs (15). The presence of NPVs in M. neustria was reported by several authors (16-31). In 2009, Demir et al.

A highly effective nucleopolyhedrovirus against Malacosoma spp. (Lepidoptera: Lasiocampidae) from Turkey: isolation, characterization, phylogeny, and virulence

“…PstI restriction analysis of both viral DNA shared the same bands and profiles. However, the KpnI and BamHI profiles of ManeNPV-T3 had more bands than the ManeNPV-T2 isolate with the same enzymes (Demir et al, 2013). Evaluation of these restriction profile differences showed that ManeNPV-T3 is different from the other ManeNPV isolates and is a new Turkish isolate of ManeNPV.…”

“…Scanning electron microscope results showed that ManeNPV-T3 has PIB sizes between 1.0 and 2.1 µm in diameter (Figure 2A). While these dimensions are greater than the PIB sizes of ManeNPV-T2 (Demir et al, 2013), the dimensions of OBs were within the usual size range of polyhedra. In a previous study, Ackermann and Smirnoff (1983) investigated the morphological characteristics of 23 baculoviruses that also include M. americanum, and reported that the mean dimensions of MaamNPV polyhedra varied between 1.1 and 1.7 µm, with an average of 1.44 µm.…”

“…Because baculoviruses are named according to the insect host species from which they were first isolated, the new NPV isolate was first thought to be a M. franconicum NPV Turkish isolate. However, phylogenetic analysis of its polh and lef-8 genes conserved among lepidopteran baculoviruses showed that it is closely related to M. neustria NPV-T2 characterized by Demir et al (2013) from Turkey, and that it was a ManeNPV infection in a field population of M. franconicum. Since it is the third isolate of M. neustria in Turkey, it was named ManeNPV-T3.…”

“…Moreover, some morphological properties of this NPV were studied by Ackermann and Smirnoff (1983), but more detailed information about this M. americanum NPV, such as restriction endonuclease enzyme profile, genome size, phylogenetic analysis, and host spectrum, was lacking. Furthermore, distinctive isolates of NPV have been studied from populations of M. neustria and have been investigated in terms of their virulence against pests (Biliotti, 1955;Günther, 1958;Magnoler, 1985;Kikhno and Strokovskaya, 1997;Jankevica et al, 1998;Demir et al, 2009aDemir et al, , 2009bDemir et al, , 2013.…”

Cloning and expression of chitinase A, B, and C (chiA, chiB, chiC) genes from Serratia marcescens originating from Helicoverpa armigera and determining their activities

“…Biopesticides and predators have a positive impact on bollworm population management (Ge and Ding 1996). Although effective systems are not yet operative against Helicoverpa sp., B. thuringiensis cry genes (Katı et al, 2007;Sevim et al, 2012) and nuclear polyhedrosis virus (Kozlav et al, 1994;Jankevica et al, 1997;Demir et al, 2013) have been utilized for M. neustria.…”