scholarly journals Genomic Diversity in a Population of Spodoptera frugiperda Nucleopolyhedrovirus

2020 ◽  
Author(s):  
Tomás Masson ◽  
María Laura Fabre ◽  
Matias Luis Pidre ◽  
José María Niz ◽  
Marcelo Facundo Berretta ◽  
...  

AbstractSpodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) represents a strong candidate to develop environmental-friendly pesticides against the fall armyworm (Spodoptera frugiperda), a widespread pest that poses a severe threat to different crops around the world. However, little is known regarding the genomic diversity present inside SfMNPV isolates and how it shapes the interactions between virus and host. Here, the genomic diversity present inside an isolate of SfMNPV was explored using high-throughput sequencing for the first time. We identified 704 intrahost single nucleotide variants, from which 184 are nonsynonymous mutations distributed among 82 different coding sequences. We detected several structural variants affecting SfMNPV genome, including two previously reported deletions inside the egt region. A comparative analysis between polymorphisms present in different SfMNPV isolates and our intraisolate diversity data suggests that coding regions with higher genetic diversity are associated with oral infectivity or unknown functions. In this context, through molecular evolution studies we provide evidence of diversifying selection acting on sf29, a putative collagenase which could contribute to the oral infectivity of SfMNPV. Overall, our results contribute to deepen our understanding of the coevolution between SfMNPV and the fall armyworm and will be useful to improve the applicability of this virus as a biological control agent.HighlightsWe characterized the genomic diversity within a population of SfMNPV.Coding regions with higher genetics diversity are associated with oral infectivity or unknown functions.Several structural variants contribute to the genomic diversity of SfMNPV.Sf29, a putative collagenase, shows signs of adaptive evolution.

Author(s):  
Tabea Allen ◽  
Marc Kenis ◽  
Lindsey Norgrove

AbstractThe fall armyworm, Spodoptera frugiperda, an American Lepidoptera, is invasive in Africa and Asia and currently one of the most damaging cereal pests in the tropics. The ichneumonid parasitoid, Eiphosoma laphygmae, is a potential classical biological control agent. We assessed existing knowledge on biology, identified natural distributions, collated reported parasitism rates from field studies and determined which other parasitoids co-occurred. We discussed the suitability of E. laphygmae for classical biological control as well as identified limitations and knowledge gaps. We conducted a systematic literature review and had 185 hits, retaining 52 papers. Reports on the natural distribution of E. laphygmae were restricted to the American tropics, ranging from North-East Mexico to Sao Paulo State, Brazil. There were only two single and unconfirmed records of it on other hosts, suggesting that the parasitoid may be specific to S. frugiperda, but this needs confirmation. In fields where E. laphygmae occurred naturally, it was the second most important contributor to fall armyworm mortality, after the braconid Chelonus insularis. On average, E. laphygmae parasitized 4.5% of fall armyworm in field studies. The highest parasitism rates were from Costa Rica (13%) and Minas Gerais, Brazil (14.5%). However, these parasitism rates are probably largely underestimated because of likely biases in sampling and parasitism rate calculations. Eiphosoma laphygmae appeared to establish better in more diverse, weedy systems. As African farming systems often have high diversity, this may favour the establishment and parasitism of E. laphygmae if eventually introduced as a classical biological control agent.


2020 ◽  
Vol 25 (4) ◽  
pp. 649-657
Author(s):  
Jianfeng Liu ◽  
Tai-An Tian ◽  
Xue-Lin Li ◽  
Yi-Chai Chen ◽  
Xiao-Fei Yu ◽  
...  

The fall armyworm (FAW), Spodoptera frugiperda Smith (Lepidoptera: Noctuidae), is one of the most damaging noctuid pests of maize and is reported in China at the beginning of 2019. It poses a serious threat to the food security of China. In order to find an attractive alternative to reduce the application of chemical insecticides, we screened different initial mite densities of Pyemotes zhonghuajia on the mortality rate of different stages of FAW and also recorded the number of P. zhonghuajia on FAW at the different times (24, 48, and 72 h). The results showed that initial mite densities had a significant effect on the mortality rates of all stages of FAW and the number of P. zhonghuajia found on the surface of FAW. One P. zhonghuajia female was able to significantly induce the mortality of FAW in the 1st to 3rd instar larvae, and the mite density of 40 could achieve 100% FAW mortality when added 1st to 5th instar larvae and prepupae. There was an increasing number of P. zhonghuajia on FAW from the 2nd to 4th instar larvae stages at all three days. These results provide the basic information for considering P. zhonghuajia as a suitable bio-control agent against FAW in China. 


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Wandee Wattanachaiyingcharoen ◽  
Ongpo Lepcha ◽  
Apichat Vitta ◽  
Det Wattanachaiyingcharoen

Abstract Background Under laboratory and greenhouse conditions, the virulence of 2 isolates of Thai indigenous entomopathogenic nematodes (EPNs) in controlling the fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera; Noctuidae), was demonstrated. Six EPNs dosages were tested against 2 larval instars of FAW under the laboratory conditions, while 2 different concentrations were tested under the greenhouse conditions. Results The results of a laboratory experiment revealed that 2 Thai indigenous EPNs isolates (Heterorhabditis indica isolate AUT 13.2 and Steinernema siamkayai isolate APL 12.3) were efficient against the FAW, 2nd and 5th larval instars. Six different nematode concentrations (50,100, 150, 200, 250 and 300 infectious juveniles (IJs) ml−1) were evaluated, and all were proven to be effective, with the mortality rate associated with concentration. Inoculated larvae in the 2nd instar was more vulnerable than that in the 5th instar. H. indica isolate AUT 13.2 was more destructive than S. siamkayai isolate APL 12.3. The greatest mortality rate of 2nd instar larvae was 83% when H. indica AUT 13.2 was applied at the concentration of 250 IJs ml−1, and 68% when the nematode S. siamkayai APL 12.3 was used at the concentration of 300 IJs ml−1. At 250 IJsml−1, the highest mortality rate of the 5th instar larvae was 45% for H. indica AUT 13.2 and 33% for S. siamkayai APL 12.3, respectively. To customize the concentration and volume of nematodes suspension evaluated in the greenhouse settings, the most sensitive stage of FAW and the optimum concentration that caused the highest mortality were used. The concentrations of both indigenous nematodes’ isolates were 20,000 and 50,000 IJsml−1 per pot, respectively, and the results showed that the mortality rates were lower than that in the laboratory. FAW mortality rate was the highest (58%) in case of the nematode H. indica isolate AUT 13.2, against (45%) in case of S. siamkayai isolate APL 12.3, at the 50,000 IJs ml−1 concentrations. Conclusions The study revealed the 2 Thai indigenous EPNs isolates (H. indica isolate AUT 13.2 and S. siamkayai isolate APL 12.3) were capable of controlling the FAW in both laboratory and greenhouse environments. The 2 Thai EPNs showed the potential to be considered as a biological control agent.


Insects ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 868
Author(s):  
Rajendra Acharya ◽  
Hwal-Su Hwang ◽  
Md Munir Mostafiz ◽  
Yeon-Su Yu ◽  
Kyeong-Yeoll Lee

The fall armyworm, Spodoptera frugiperda, which is native to Central and South America, has recently invaded Africa and Asia, causing serious damage to various crops. Although management to date has been largely unsuccessful, entomopathogenic nematodes (EPNs) are a potential biological control agent that could be used to control the late larval and pupal stages of S. frugiperda that dwell under the ground. Here, we compared the virulence of seven EPNs against larval and pupal stages of S. frugiperda. In a Petri dish assay, both Heterorhabditis indica and Steinernema carpocapsae were highly virulent against younger larvae, whereas S. arenarium and S. longicaudum were highly virulent against older larvae. In contrast, H. bacteriophora, Heterorhabditis sp., and S. kushidai showed low virulence against all larval stages. In soil column and pot assays, H. indica, S. carpocapsae, and S. longicaudum were highly virulent against late larval and pupal stages compared with the other EPN species. Thus, H. indica, S. carpocapsae, and S. longicaudum are recommended for the biological control of S. frugiperda. Our study provides important information of EPNs for the practical application of biological control of fall armyworm.


2020 ◽  
Author(s):  
Katrina A. Schlum ◽  
Kurt Lamour ◽  
Caroline Placidi de Bortoli ◽  
Rahul Banerjee ◽  
Scott J. Emrich ◽  
...  

AbstractThe fall armyworm (Spodoptera frugiperda (J.E. Smith)) is a highly polyphagous agricultural pest with long-distance migratory behavior threatening food security worldwide. This pest has a host range of >80 plant species, but two host strains are recognized based on their association with corn (C-strain) or rice and smaller grasses (R-strain). In this study, the population structure and genetic diversity in 55 S. frugiperda samples from Argentina, Brazil, Kenya, Puerto Rico and the United States (USA) were surveyed to further our understanding of whole genome nuclear diversity. Comparisons at the genomic level suggest panmixia in this population, other than a minor reduction in gene flow between the two overwintering populations in the continental USA that also corresponded to genetically distinct host strains. Two maternal lines were detected from analysis of mitochondrial genomes. We found members from the Eastern Hemisphere interspersed within both continental USA overwintering subpopulations, suggesting multiple individuals were likely introduced to Africa. Comparisons between laboratory-reared and field collected S. frugiperda support similar genomic diversity, validating the experimental use of laboratory strains. Our research is the largest diverse collection of United States S. frugiperda whole genome sequences characterized to date, covering eight continental states and a USA territory (Puerto Rico). The genomic resources presented provide foundational information to understand gene flow at the whole genome level among S. frugiperda populations.


2021 ◽  
Author(s):  
Azza Althagafi ◽  
Lamia Alsubaie ◽  
Nagarajan Kathiresan ◽  
Katsuhiko Mineta ◽  
Taghrid Aloraini ◽  
...  

AbstractMotivationStructural genomic variants account for much of human variability and are involved in several diseases. Structural variants are complex and may affect coding regions of multiple genes, or affect the functions of genomic regions in different ways from single nucleotide variants. Interpreting the phenotypic consequences of structural variants relies on information about gene functions, haploinsufficiency or triplosensitivity, and other genomic features. Phenotype-based methods to identifying variants that are involved in genetic diseases combine molecular features with prior knowledge about the phenotypic consequences of altering gene functions. While phenotype-based methods have been applied successfully to single nucleotide variants, as well as short insertions and deletions, the complexity of structural variants makes it more challenging to link them to phenotypes. Furthermore, structural variants can affect a large number of coding regions, and phenotype information may not be available for all of them.ResultsWe developed DeepSVP, a computational method to prioritize structural variants involved in genetic diseases by combining genomic information with information about gene functions. We incorporate phenotypes linked to genes, functions of gene products, gene expression in individual celltypes, and anatomical sites of expression, and systematically relate them to their phenotypic consequences through ontologies and machine learning. DeepSVP significantly improves the success rate of finding causative variants in several benchmarks and can identify novel pathogenic structural variants in consanguineous families.Availabilityhttps://github.com/bio-ontology-research-group/[email protected]


Sociobiology ◽  
2017 ◽  
Vol 64 (4) ◽  
pp. 477 ◽  
Author(s):  
Matheus Montefusco Oliveira ◽  
Flávia Batista Gomes ◽  
Alexandre Somavilla ◽  
Cristiane Krug

Wasps of the genus Polistes (Vespidae: Polistinae) are eusocial, considered valuable biological control agents. The objective of this work was to determine the resources collected by Polistes canadensis wasps, evaluate their performance and importance as a natural enemy and possible agent of biological control in the Brazilian Amazon. Between 8 October and 20 November of 2014, 20 evaluations were performed, totalizing 101 hours of observations of the foraging activity of an aggregation out in stage of development post-emergence with approximately 50 adult individuals distributed in 15 colonies. Additionally, observations of the predatory activity of Polistes canadensis on Plutella xylostella on a small organic plantation of kale (Brassica oleracea L. var. acephala DC), were also made. During the evaluations 1742 returns were recorded, 11.72% of them with prey, 3.10% with plant fiber, 16.76% with nectar, 45.17% with water and 23.25% without any visible load. All the preys identified were classified as Lepidoptera, belonging to ten morphospecies. Only one morphospecies was identified as Spodoptera frugiperda, which was the most commonly resource used by the wasps in 37 % in immature feeding. Only returns with nectar had statistically significant difference between the evaluated schedules.  Polistes canadensis wasps did not prey Plutella xylostella caterpillars. The wasp aggregation studied was able to prey an average of 10.2 caterpillars per day, which demonstrates the potential of this species for the biological control of pests in the Amazon region.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8701 ◽  
Author(s):  
Joseph Gichuhi ◽  
Subramanian Sevgan ◽  
Fathiya Khamis ◽  
Johnnie Van den Berg ◽  
Hannalene du Plessis ◽  
...  

Background The invasive fall armyworm, Spodoptera frugiperda (J.E. Smith) is a polyphagous pest that causes widespread damage particularly to maize and sorghum in Africa. The microbiome associated with S. frugiperda could play a role in the insects’ success and adaptability. However, bacterial communities in S. frugiperda remain poorly studied. Methods We investigated the composition, abundance and diversity of microbiomes associated with larval and adult specimens of S. frugiperda collected from four maize growing regions in Kenya through high throughput sequencing of the bacterial 16S rRNA gene. The population structure of S. frugiperda in Kenya was assessed through amplification of the mitochondrial cytochrome oxidase subunit I gene. Results We identified Proteobacteria and Firmicutes as the most dominant bacterial phyla and lesser proportions of Bacteroidetes and Actinobacteria. We also observed differences in bacterial microbiome diversity between larvae and adults that are a likely indication that some prominent larval bacterial groups are lost during metamorphosis. However, several bacterial groups were found in both adults and larvae suggesting that they are transmitted across developmental stages. Reads corresponding to several known entomopathogenic bacterial clades as well as the fungal entomopathogen, Metarhizium rileyi, were observed. Mitochondrial DNA haplotyping of the S. frugiperda population in Kenya indicated the presence of both “Rice” and “Corn” strains, with a higher prevalence of the “Rice” strain.


2015 ◽  
Vol 148 (1) ◽  
pp. 112-117 ◽  
Author(s):  
Agustín Hernández-Juárez ◽  
Luis A. Aguirre-Uribe ◽  
Aideé González-Ruíz ◽  
Julio C. Chacón-Hernández ◽  
Jerónimo Landeros-Flores ◽  
...  

AbstractThe effect of the insecticide endosulfan on the predatory efficiency of the green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae) on the eggs of tobacco budworm, Heliothis virescens (Fabricius) (Lepidoptera: Noctuidae) and fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) was measured with Holling’s disc equation. Though the type II functional response was maintained in C. carnea exposed to endosulfan, the functional response parameters: attack rate (a′), handling time (Th), total handling time (Tht), searching time (Ts), and search efficiency (E) were affected for both prey offered. The predator took more time to identify, pursue, capture, consume, and digest the prey, and in general, the efficiency of the predator as a biological control agent was adversely affected.


2019 ◽  
Vol 110 (2) ◽  
pp. 270-277
Author(s):  
S. Pineda ◽  
O. Hernández-Quintero ◽  
Y. B. Velázquez-Rodríguez ◽  
E. Viñuela ◽  
J. I. Figueroa ◽  
...  

AbstractPredation by Engytatus varians (Distant) adults on different development stages of the prey species Bactericera cockerelli (Sulcer) (egg, second, and third nymphal instars), Spodoptera exigua (Hübner) and Spodoptera frugiperda (J. E. Smith) (egg, first, and second larval instars) was evaluated using tomato (Solanum lycopersicum L.) leaflets or plants. These insects are the primary pest of several agriculturally important crops. The influence of E. varians age on the predation capacity was also analysed. Engytatus varians females consumed significantly more B. cockerelli eggs and nymphs than males. Additionally, female predators consumed significantly more second than third instar prey at two predator ages, while males consumed significantly more the second instar than third instar prey at all predator ages. In most of the cases, females also consumed significantly more S. exigua and S. frugiperda eggs than males; however, in terms of larvae consumption, this difference was observed only in some predator ages. Females consumed more the first than second instar S. exigua than males, whereas this behaviour was only observed in males when the predators were 15 and 17 days old. No significant differences were observed in the consumption of first and second instar of S. frugiperda for both sexes of the predators. Predator age did not cause any systematic effects on the predation rates of any prey species. Based on these results, we confirmed that E. varians has potential as a biological control agent for B. cockerelli and also for the Spodoptera species bioassayed.


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