Enhancing effect of proteins derived from Xestia c-nigrum granulovirus on Mamestra brassicae nucleopolyhedrovirus infection in larvae of Autographa nigrisigna (Lepidoptera: Noctuidae) on cabbage

Spodoptera frugiperda (Lepidoptera: Noctuidae) is a major pest in maize crops in Colombia, and affects several regions in America. A granulovirus isolated from S. frugiperda (SfGV VG008) has potential as an enhancer of insecticidal activity of previously described nucleopolyhedrovirus from the same insect species (SfMNPV). The SfGV VG008 genome was sequenced and analyzed showing circular double stranded DNA of 140,913 bp encoding 146 putative ORFs that include 37 Baculoviridae core genes, 88 shared with betabaculoviruses, two shared only with betabaculoviruses from Noctuide insects, two shared with alphabaculoviruses, three copies of own genes (paralogs) and the other 14 corresponding to unique genes without representation in the other baculovirus species. Particularly, the genome encodes for important virulence factors such as 4 chitinases and 2 enhancins. The sequence analysis revealed the existence of eight homologous regions (hrs) and also suggests processes of gene acquisition by horizontal transfer including the SfGV VG008 ORFs 046/047 (paralogs), 059, 089 and 099. The bioinformatics evidence indicates that the genome donors of mentioned genes could be alpha- and/or betabaculovirus species. The previous reported ability of SfGV VG008 to naturally co-infect the same host with other virus show a possible mechanism to capture genes and thus improve its fitness.

Section: Introductionmentioning

confidence: 99%

The Complete Sequence of the First Spodoptera frugiperda Betabaculovirus Genome: A Natural Multiple Recombinant Virus

Cuartas

Barrera

Belaich

et al. 2015

“…Similar to the first trial, the addition of GVPs significantly reduced the LT 50 of NPV infected larvae ( Table 4 ). Our previous bioassays using the second instar larvae of M. brassicae [ 38 ], H. armigera [ 39 , 40 ] and A. nigrisigna [ 41 ] indicated the effect of GVPs not only increases the infectivity of MabrNPV but also shortens the lethal time and/or causes death at a younger instar. These trials in 2008 verified the desirable effects of GVPs on MabrNPV infection in the cabbage field.…”

Section: Discussionmentioning

confidence: 99%

“…Our previous study confirmed that XecnGV had proteins with potency to improve the efficiency of NPV in their capsules [ 38 ]. Our detailed bioassays using an artificial diet or cabbage seedling revealed that a combination of MabrNPV with proteins derived from XecnGV capsules (GVPs) improves the insecticidal activity of MabrNPV against not only M. brassicae but also H. armigera and Autographa nigrisigna [ 38 , 39 , 40 , 41 ], suggesting prospects for a new biological insecticide against three important noctuid pests of cruciferous crops. Since the insecticidal activity and persistence of viruses in the field are affected by environmental factors—for example sunlight, rainfall, and temperature—as well as biotic factors such as density and age structure of the pest population, field studies would be necessary to evaluate the efficacy of the combined formulation of MabrNPV with GVPs on the control of these noctuid pests.…”

Section: Introductionmentioning

confidence: 99%

Two Year Field Study to Evaluate the Efficacy of Mamestra brassicae Nucleopolyhedrovirus Combined with Proteins Derived from Xestia c-nigrum Granulovirus

Goto

Mukawa

Mitsunaga

2015

Self Cite

Japan has only three registered baculovirus biopesticides despite its long history of studies on insect viruses. High production cost is one of the main hindrances for practical use of baculoviruses. Enhancement of insecticidal effect is one possible way to overcome this problem, so there have been many attempts to develop additives for baculoviruses. We found that alkaline soluble proteins of capsules (GVPs) of Xestia c-nigrum granulovirus can increase infectivity of some viruses including Mamestra brassicae nucleopolyhedrovirus (MabrNPV), and previously reported that MabrNPV mixed with GVPs was highly infectious to three important noctuid pests of vegetables in the following order, Helicoverpa armigera, M. brassicae, and Autographa nigrisigna. In this study, small-plot experiments were performed to assess concentrations of MabrNPV and GVPs at three cabbage fields and a broccoli field for the control of M. brassicae. In the first experiment, addition of GVPs (10 µg/mL) to MabrNPV at 106 OBs/mL resulted in a significant increase in NPV infection (from 53% to 66%). In the second experiment, the enhancing effect of GVP on NPV infection was confirmed at 10-times lower concentrations of MabrNPV. In the third and fourth experiments, a 50% reduction in GVPs (from 10 µg/mL to 5 µg/mL) did not result in a lowering of infectivity of the formulations containing MabrNPV at 105 OBs/mL. These results indicate that GVPs are promising additives for virus insecticides.

“…Several studies have employed NPVs with extracts of GV OBs, as the proteins possessing enhancing activity do not need further purification. GVP obtained from XcenGV were successfully used as additives for MbMNPV on Mamestra brassicae , Helicoverpa armigera , and Autographa nigrisigna larvae [ 43 , 44 , 45 , 46 , 47 ].…”

Section: Baculovirus Interactions In Vivomentioning

confidence: 99%

Effects of Mixed Baculovirus Infections in Biological Control: A Comprehensive Historical and Technical Analysis

Ferrelli,

Salvador

2023

Baculoviruses are insect-specific DNA viruses that have been exploited as bioinsecticides for the control of agricultural and forest pests around the world. Mixed infections with two different baculoviruses have been found in nature, infecting the same host. They have been studied to understand the biology of virus interactions, their effects on susceptible insects, and their insecticidal implications. In this work, we summarize and analyze the in vivo baculovirus co-infections reported in the literature, mainly focusing on pest biocontrol applications. We discuss the most common terms used to describe the effects of mixed infections, such as synergism, neutralism, and antagonism, and how to determine them based on host mortality. Frequently, baculovirus co-infections found in nature are caused by a combination of a nucleopolyhedrovirus and a granulovirus. Studies performed with mixed infections indicated that viral dose, larval stage, or the presence of synergistic factors in baculovirus occlusion bodies are important for the type of virus interaction. We also enumerate and discuss technical aspects to take into account in studies on mixed infections, such as statistical procedures, quantification of viral inocula, the selection of instars, and molecular methodologies for an appropriate analysis of baculovirus interaction. Several experimental infections using two different baculoviruses demonstrated increased viral mortality or a synergistic effect on the target larvae compared to single infections. This can be exploited to improve the baculovirus-killing properties of commercial formulations. In this work, we offer a current overview of baculovirus interactions in vivo and discuss their potential applications in pest control strategies.