Parasitism by Cotesia plutellae alters the hemocyte population and immunological function of the diamondback moth, Plutella xylostella

Ibrahim, Ahmed M. A.; Kim, Yonggyun

doi:10.1016/j.jinsphys.2006.06.001

Cited by 99 publications

(63 citation statements)

References 33 publications

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“…In this stage, 30 caterpillars per treatment were used; a small hole was made with a sterile entomological pin between the first and second proleg and hemolymph was collected. A sample of 5 μ L of hemolymph was collected and added to an Eppendorf tube with 20 μ L anticoagulant buffer (98 mmol/L NaOH, 186 mmol/L NaCl, 17 mmol/L Na2 EDTA, and 41 mmol/L Citric acid, pH 4.5) plus 12 μ L of Giemsa stain [adapted from Ibrahim and Kim (2006)]. Two aliquots of 8 μ L of the suspension were added in each side of a Neubauer improved chamber and total hemocytes were counted under a microscope.…”

Section: Methodsmentioning

confidence: 99%

Temperature and population density: interactional effects of environmental factors on phenotypic plasticity, immune defenses, and disease resistance in an insect pest

Silva

Elliot

2016

Ecology and Evolution

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Temperature and crowding are key environmental factors mediating the transmission and epizooty of infectious disease in ectotherm animals. The host physiology may be altered in a temperature‐dependent manner and thus affects the pathogen development and course of diseases within an individual and host population, or the transmission rates (or infectivity) of pathogens shift linearly with the host population density. To our understanding, the knowledge of interactive and synergistic effects of temperature and population density on the host–pathogen system is limited. Here, we tested the interactional effects of these environmental factors on phenotypic plasticity, immune defenses, and disease resistance in the velvetbean caterpillar Anticarsia gemmatalis. Upon egg hatching, caterpillars were reared in thermostat‐controlled chambers in a 2 × 4 factorial design: density (1 or 8 caterpillars/pot) and temperature (20, 24, 28, or 32°C). Of the immune defenses assessed, encapsulation response was directly affected by none of the environmental factors; capsule melanization increased with temperature in both lone‐ and group‐reared caterpillars, although the lone‐reared ones presented the most evident response, and hemocyte numbers decreased with temperature regardless of the population density. Temperature, but not population density, affected considerably the time from inoculation to death of velvetbean caterpillar. Thus, velvetbean caterpillars succumbed to Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) more quickly at higher temperatures than at lower temperatures. As hypothesized, temperature likely affected caterpillars' movement rates, and thus the contact between conspecifics, which in turn affected the phenotypic expression of group‐reared caterpillars. Our results suggest that environmental factors, mainly temperature, strongly affect both the course of disease in velvetbean caterpillar population and its defenses against pathogens. As a soybean pest, velvetbean caterpillar may increase its damage on soybean fields under a scenario of global warming as caterpillars may reach the developmental resistance faster, and thus decrease their susceptibility to biological control by AgMNPV.

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Section: Methodsmentioning

confidence: 99%

Temperature and population density: interactional effects of environmental factors on phenotypic plasticity, immune defenses, and disease resistance in an insect pest

Silva

Elliot

2016

Ecology and Evolution

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“…Parasitized larvae exhibit severe immunosuppression in both cellular and humoral immune responses (Ibrahim & Kim, 2006;Nalini & Kim, 2007;Bae & Kim, 2009). Among several parasitic factors, CpBV is regarded as a main parasitic factor in host regulation presumably with 157 encoded genes including viral histone H4 (Chen et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Suppressive activity of a viral histone H4 against two host chromatin remodelling factors: lysine demethylase and SWI/SNF

Kumar

Venkata

Kim

2016

Journal of General Virology

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Histone H4, a nucleosome subunit in eukaryotes, plays crucial roles in DNA package and regulation of gene expression through covalent modification. A viral histone H4 encoded in Cotesia plutellae bracovirus (CpBV), a polydnavirus, is called CpBV-H4. It is highly homologous to other histone H4 proteins excepting 38 extra amino acid residues in the N terminus. CpBV-H4 can form octamer with other histone subunits and alter host gene expression. In this study, CpBV-H4 was transiently expressed in a natural host (Plutella xylostella) and its suppressive activity on host gene expression was evaluated by the suppressive subtractive hybridization (SSH) technique. The SSH targets down-regulated by CpBV-H4 were read with the 454 pyrosequencing platform and annotated using the genome of P. xylostella. The down-regulated genes (610 contigs) were annotated in most functional categories based on gene ontology. Among these SSH targets, 115 genes were functionally distinct, including two chromatin remodelling factors: a lysine-specific demethylase (Px-KDM) and a chromatin remodelling complex [Px-SWI/SNF (SWItch/Sucrose Non-Fermentable)]. Px-KDM was highly expressed in all tested tissues during the entire larval period. Suppression of Px-KDM expression by specific RNA interference (RNAi) significantly (P<0.05) reduced haemocyte nodule formation in response to immune challenge and impaired both larval and pupal development. Px-SWI/SNF was expressed in all developmental stages. Suppression of Px-SWI/SNF expression by RNAi reduced cellular immune response and interfered with adult metamorphosis. These results suggest that CpBV-H4 can alter host gene expression by interfering with chromatin modification and remodelling factors in addition to its direct epigenetic control activity.

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“…PDVs harbor large multigene families that are often implicated in immunosuppression and immunoevasion in parasitized hosts (17). CpBV is regarded as a major factor in reducing cellular immune capacity in parasitized P. xylostella (18,19).…”

Section: Discussionmentioning

confidence: 99%

A SERI technique reveals an immunosuppressive activity of a serine-rich protein encoded in Cotesia plutellae bracovirus

Barandoc

Park²,

Kim³

2010

BMB Reports

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Parasitism by Cotesia plutellae alters the hemocyte population and immunological function of the diamondback moth, Plutella xylostella

Cited by 99 publications

References 33 publications

Temperature and population density: interactional effects of environmental factors on phenotypic plasticity, immune defenses, and disease resistance in an insect pest

Temperature and population density: interactional effects of environmental factors on phenotypic plasticity, immune defenses, and disease resistance in an insect pest

Suppressive activity of a viral histone H4 against two host chromatin remodelling factors: lysine demethylase and SWI/SNF

A SERI technique reveals an immunosuppressive activity of a serine-rich protein encoded in Cotesia plutellae bracovirus

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