scholarly journals Effective Gene Silencing in a Microsporidian Parasite Associated with Honeybee (Apis mellifera) Colony Declines

2010 ◽  
Vol 76 (17) ◽  
pp. 5960-5964 ◽  
Author(s):  
Nitzan Paldi ◽  
Eitan Glick ◽  
Maayan Oliva ◽  
Yaron Zilberberg ◽  
Lucie Aubin ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Microsporidian Parasite ◽  
Colony Losses ◽  
Prevalent Disease ◽  
Systemic Rnai ◽  
Genome Sequencing Effort ◽  
Honeybee Colony ◽  
Disease Agent ◽  
Cellular Components ◽  
Basal Fungi

ABSTRACT Honeybee colonies are vulnerable to parasites and pathogens ranging from viruses to vertebrates. An increasingly prevalent disease of managed honeybees is caused by the microsporidian Nosema ceranae. Microsporidia are basal fungi and obligate parasites with much-reduced genomic and cellular components. A recent genome-sequencing effort for N. ceranae indicated the presence of machinery for RNA silencing in this species, suggesting that RNA interference (RNAi) might be exploited to regulate Nosema gene expression within bee hosts. Here we used controlled laboratory experiments to show that double-stranded RNA homologous to specific N. ceranae ADP/ATP transporter genes can specifically and differentially silence transcripts encoding these proteins. This inhibition also affects Nosema levels and host physiology. Gene silencing could be mediated solely by Nosema or in concert with known systemic RNAi mechanisms in their bee hosts. These results are novel for the microsporidia and provide a possible avenue for controlling a disease agent implicated in severe honeybee colony losses. Moreover, since microsporidia are pathogenic in several known veterinary and human diseases, this advance may have broader applications in the future for disease control.

scholarly journals Managed honeybee colony losses of the Eastern honeybee (Apis cerana) in China (2011–2014)

Apidologie ◽  
2017 ◽  
Vol 48 (5) ◽  
pp. 692-702 ◽  
Author(s):  
Chao Chen ◽  
Zhiguang Liu ◽  
Yuexiong Luo ◽  
Zheng Xu ◽  
Shunhai Wang ◽  
...  
Keyword(s):  
Apis Cerana ◽  
Colony Losses ◽  
Honeybee Colony

scholarly journals A genome-wide screening for RNAi pathway proteins in Acari

2020 ◽  
Author(s):  
Beatrice T Nganso ◽  
Noa Sela ◽  
Victoria Soroker
Keyword(s):  
Gene Silencing ◽  
Micro Rna ◽  
Rnai Pathway ◽  
Comparative Genomic ◽  
Specific Gene ◽  
C Elegans ◽  
Conserved Sequence ◽  
A Genome ◽  
Systemic Rnai ◽  
Amplification Mechanism

Abstract Background RNA interference (RNAi) is a highly conserved, sequence-specific gene silencing mechanism present in Eukaryotes. Three RNAi pathways critical for organismal development and survival are known, namely micro-RNA (miRNA), Piwi-interacting RNA (piRNA) and short interfering RNA (siRNA) pathways. Little knowledge exist about the genes involved in these pathways in Acari. Moreover, variable successes has been obtained in gene knockdown via siRNA pathway in functional genomics and management of Acari species. We hypothesized that the clue may be in the variability in the composition and the efficacy of siRNAi machinery among Acari. Results Both comparative genomic analyses and domain annotation suggest that all the analyzed species have orthologs of genes that mediate gene silencing via the three RNAi pathways though gene duplication and/or loss have occurred in the different species. We also identified orthologs of Caenorhabditis elegans RNA-dependent RNA polymerase (RdRP) gene in all Acari species though no secondary Argonaute homologs that operate with this gene in siRNA amplification mechanism were found. This finding suggests that the siRNA amplification mechanism present in Acari may be distinct from that described in C. elegans . Moreover, the genomes of these Acari species encode no ortholog of C. elegans systemic RNAi defective 1 (Sid-1) that mediate systemic RNAi, suggesting that the phenomena of systemic and parental RNAi that has been reported in some Acari species probably occur through a different mechanism. Orthologs of RNAi spreading defective-3 (Rsd-3) gene and scavenger receptors namely Eater and SR-CI that mediate endocytosis cellular update of dsRNA in C. elegans and Drosophila melanogaster were found in Acari genomes. This result suggests that cellular dsRNA uptake in Acari is endocytosis-dependent. Detailed phylogenetic analyses of core RNAi pathway genes in the studied Acari species revealed that their evolution is compatible with the proposed monophyletic evolution of this group. Conclusions Taken together, our in silico comparative analyses have revealed the potential activity of all three pathways in Acari. However, much experimental work remains to be done in elucidating the operating mechanisms behind these pathways in particular those that govern systemic/parental RNAi and siRNA amplification in Acari.

scholarly journals Direct Economic Impact Assessment of Winter Honeybee Colony Losses in Three European Countries

Agriculture ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 398
Author(s):  
Despina Popovska Stojanov ◽  
Lazo Dimitrov ◽  
Jiří Danihlík ◽  
Aleksandar Uzunov ◽  
Miroljub Golubovski ◽  
...  
Keyword(s):  
Economic Impact ◽  
Management Practices ◽  
Agricultural Sector ◽  
Stress Factors ◽  
Economic Losses ◽  
Colony Losses ◽  
Economic Impact Assessment ◽  
Parasitic Mite ◽  
Honeybee Colony ◽  
Pioneer Effort

Honeybees are of great importance because of their role in pollination as well as for hive products. The population of managed colonies fluctuates over time, and recent monitoring reports show different levels of colony losses in many regions and countries. The cause of this kind of loss is a combination of various factors, such as the parasitic mite Varroa destructor, viruses, pesticides, management practices, climate change, and other stress factors. Having in mind that the economic aspect of honeybee colony losses has not been estimated, a pioneer effort was made for developing a methodology that estimates the economic impact of honeybee colony losses. Winter loss data was based on 2993 answers of the COLOSS standard questionnaire survey of honeybee winter colony losses for 2016/2017. In addition, market and financial data were used for each country. In a comparative analysis, an assessment on the economic impact of colony losses in Austria, Czechia, and Macedonia was made. The estimation considered the value of the colonies and the potential production losses of the lost colonies and of surviving but weak colonies. The direct economic impact of winter honeybee colony losses in 2016/2017 in Austria was estimated to be about 32 Mio €; in Czechia, 21 Mio €; and in Macedonia, 3 Mio €. Economic impact reflects the different value levels in the three countries, national colony populations, and the magnitude of colony losses. This study also suggests that economic losses are much higher than the subsidies, which underlines the economic importance of honeybees for the agricultural sector.

scholarly journals Honeybee colony losses in Uruguay during 2013–2014

Apidologie ◽  
2016 ◽  
Vol 48 (3) ◽  
pp. 364-370 ◽  
Author(s):  
Karina Antúnez ◽  
Ciro Invernizzi ◽  
Yamandú Mendoza ◽  
Dennis vanEngelsdorp ◽  
Pablo Zunino
Keyword(s):  
Colony Losses ◽  
Honeybee Colony

scholarly journals Haemolymph removal by Varroa mite destabilizes the dynamical interaction between immune effectors and virus in bees, as predicted by Volterra's model

2019 ◽  
Vol 286 (1901) ◽  
pp. 20190331 ◽  
Author(s):  
Desiderato Annoscia ◽  
Sam P. Brown ◽  
Gennaro Di Prisco ◽  
Emanuele De Paoli ◽  
Simone Del Fabbro ◽  
...  
Keyword(s):  
Viral Evolution ◽  
Colony Losses ◽  
Viral Pathogen ◽  
Dynamical Interaction ◽  
Deformed Wing Virus ◽  
Pathogen Virulence ◽  
Mite Feeding ◽  
Parasitic Mite ◽  
Honeybee Colony ◽  
Honeybee Health

The association between the deformed wing virus and the parasitic mite Varroa destructor has been identified as a major cause of worldwide honeybee colony losses. The mite acts as a vector of the viral pathogen and can trigger its replication in infected bees. However, the mechanistic details underlying this tripartite interaction are still poorly defined, and, particularly, the causes of viral proliferation in mite-infested bees. Here, we develop and test a novel hypothesis that mite feeding destabilizes viral immune control through the removal of both virus and immune effectors, triggering uncontrolled viral replication. Our hypothesis is grounded on the predator–prey theory developed by Volterra, which predicts prey proliferation when both predators and preys are constantly removed from the system. Consistent with this hypothesis, we show that the experimental removal of increasing volumes of haemolymph from individual bees results in increasing viral densities. By contrast, we do not find consistent support for alternative proposed mechanisms of viral expansion via mite immune suppression or within-host viral evolution. Our results suggest that haemolymph removal plays an important role in the enhanced pathogen virulence observed in the presence of feeding Varroa mites. Overall, these results provide a new model for the mechanisms driving pathogen–parasite interactions in bees, which ultimately underpin honeybee health decline and colony losses.

scholarly journals Systemic RNAi mediated gene silencing in the anhydrobiotic nematode Panagrolaimus superbus

2008 ◽  
Vol 9 (1) ◽  
pp. 58 ◽  
Author(s):  
Adam J Shannon ◽  
Trevor Tyson ◽  
Ilona Dix ◽  
Jacqueline Boyd ◽  
Ann M Burnell
Keyword(s):  
Gene Silencing ◽  
Systemic Rnai

scholarly journals Systemic RNAi-mediated Gene Silencing in Nonhuman Primate and Rodent Myeloid Cells

2012 ◽  
Vol 1 ◽  
pp. e4 ◽  
Author(s):  
Tatiana I Novobrantseva ◽  
Anna Borodovsky ◽  
Jamie Wong ◽  
Boris Klebanov ◽  
Mohammad Zafari ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Nonhuman Primate ◽  
Myeloid Cells ◽  
Systemic Rnai

scholarly journals A genome-wide screening for RNAi pathway genes in Acari

2020 ◽  
Author(s):  
Victoria Soroker ◽  
Beatrice T Nganso ◽  
Noa Sela
Keyword(s):  
Gene Silencing ◽  
Micro Rna ◽  
Rnai Pathway ◽  
Comparative Genomic ◽  
Specific Gene ◽  
C Elegans ◽  
Conserved Sequence ◽  
A Genome ◽  
Systemic Rnai ◽  
Amplification Mechanism

Abstract BackgroundRNA interference (RNAi) is a highly conserved, sequence-specific gene silencing mechanism present in Eukaryotes. Three RNAi pathways critical for organismal development and survival are known, namely micro-RNA (miRNA), Piwi-interacting RNA (piRNA) and short interfering RNA (siRNA) pathways. Little knowledge exist about the genes involved in these pathways in Acari. Moreover, variable successes has been obtained in gene knockdown via siRNA pathway in functional genomics and management of Acari species. We hypothesized that the clue may be in the variability in the composition and the efficacy of siRNAi machinery among Acari. ResultsBoth comparative genomic analyses and domain annotation suggest that all the analyzed species have orthologs of genes that mediate gene silencing via the three RNAi pathways though gene duplication and/or loss have occurred in the different species. We also identified orthologs of Caenorhabditis elegans RNA-dependent RNA polymerase (RdRP) gene in all Acari species though no secondary Argonaute homologs that operate with this gene in siRNA amplification mechanism were found. This finding suggests that the siRNA amplification mechanism present in Acari may be distinct from that described in C. elegans. Moreover, the genomes of these Acari species encode no ortholog of C. elegans systemic RNAi defective 1 (Sid-1) that mediate systemic RNAi, suggesting that the phenomena of systemic and parental RNAi that has been reported in some Acari species probably occur through a different mechanism. Orthologs of RNAi spreading defective-3 (Rsd-3) gene and scavenger receptors namely Eater and SR-CI that mediate endocytosis cellular update of dsRNA in C. elegans and Drosophila melanogaster were found in Acari genomes. This result suggests that cellular dsRNA uptake in Acari is endocytosis-dependent. Detailed phylogenetic analyses of core RNAi pathway genes in the studied Acari species revealed that their evolution is compatible with the proposed monophyletic evolution of this group.ConclusionsTaken together, our in silico comparative analyses have revealed the potential activity of all three pathways in Acari. However, much experimental work remains to be done in elucidating the operating mechanisms behind these pathways in particular those that govern systemic/parental RNAi and siRNA amplification in Acari.

RNA interference in plant parasitic nematodes: a summary of the current status

Parasitology ◽  
2012 ◽  
Vol 139 (5) ◽  
pp. 630-640 ◽  
Author(s):  
C. J. LILLEY ◽  
L. J. DAVIES ◽  
P. E. URWIN
Keyword(s):  
Rna Interference ◽  
Gene Silencing ◽  
Cell Types ◽  
Current Status ◽  
Parasitic Nematodes ◽  
Rnai Phenotype ◽  
Plant Parasitic Nematodes ◽  
Systemic Rnai ◽  
Plant Parasitic

SUMMARYRNA interference (RNAi) has emerged as an invaluable gene-silencing tool for functional analysis in a wide variety of organisms, particularly the free-living model nematode Caenorhabditis elegans. An increasing number of studies have now described its application to plant parasitic nematodes. Genes expressed in a range of cell types are silenced when nematodes take up double stranded RNA (dsRNA) or short interfering RNAs (siRNAs) that elicit a systemic RNAi response. Despite many successful reports, there is still poor understanding of the range of factors that influence optimal gene silencing. Recent in vitro studies have highlighted significant variations in the RNAi phenotype that can occur with different dsRNA concentrations, construct size and duration of soaking. Discrepancies in methodology thwart efforts to reliably compare the efficacy of RNAi between different nematodes or target tissues. Nevertheless, RNAi has become an established experimental tool for plant parasitic nematodes and also offers the prospect of being developed into a novel control strategy when delivered from transgenic plants.

Sign in / Sign up

Export Citation Format

Share Document