The whitefly Bemisia tabaci are considered as a taxonomically complex that contained some destructive pests.Two of the most prevalent cryptic species are B.tabaci Middle East-Asia Minor 1(MEAM1)and Mediterranean(MED)....The whitefly Bemisia tabaci are considered as a taxonomically complex that contained some destructive pests.Two of the most prevalent cryptic species are B.tabaci Middle East-Asia Minor 1(MEAM1)and Mediterranean(MED).In an extensive field survey of the B.tabaci complex present throughout part of China from 2004 to 2007,we obtained 93 samples of B.tabaci from 22 provinces.We determined that these Chinese haplotypes included 2 invasive species(MEAM1 and MED),and 4 indigenous cryptic species(Asia II 1,Asia II 3,China 3 and Asia II 7)by sequencing mitochondrial cytochrome oxidose one gene(mtCOI).The diversity and genetic differentiation of a subset of 19 populations of B.tabaci were studied using cDNA amplified fragment length polymorphism(AFLP).Prior to 2007,MEAM1 was a dominant species in many provinces in China.By 2007,MED was dominant in 11 provinces.Both invasive and indigenous species were simultaneously found in some regions.Indigenous species of B.tabaci were found in six provinces in southern China.MED and MEAM1 have broad ranges of host plants,and indigenous species appeared to have much narrower host ranges.All Asia II 3 samples were found on cotton except one on aubergine.China 3 has more host plants than Asia II 3.Twelve samples of China 3 were collected from sweet potato,Japanese hop,squash and cotton.A total of 677 reproducible bands amplified with 5 AFLP primer combinations were obtained.The highest proportion of polymorphic bands was 98.7% and the lowest was 91.9%.Unweighted pair-group method analysis indicated that the clustering was independent of the different species.MED showed the lowest degree of similarity than the other species.The data indicate that both MEAM1and MED were rapidly established in China.展开更多
Bemisia tabaci adults from various host-plant species were collected from 31 regions across India.266 B.tabaci samples were first screened by RAPD-PCR to examine molecular variability and to select individuals with di...Bemisia tabaci adults from various host-plant species were collected from 31 regions across India.266 B.tabaci samples were first screened by RAPD-PCR to examine molecular variability and to select individuals with different fingerprints.Host-plant and region of collection were then used to select 25 individuals for PCR amplification and sequencing of their partial mitochondrial cytochrome oxidase subunit one(mtCOI)genes.Pairwise comparisons with mtCOI consensus sequences showed that the majority of these samples had <3.5% sequence divergence from groups currently termed Asia I,Asia II-5,Asia II-7,and Asia II-8.The biotype-B B.tabaci from India clustered into the Middle East-Asia Minor 1 group.A new group of B.tabaci from Coimbatore,collected from pumpkin,was related most closely to the Asia I group(6.2% sequence divergence from the consensus Asia I sequence).To increase our understanding of the epidemiology of tomato leaf curl disease(ToLCD)and the key B.tabaci genetic groups involved in virus spread,the indigenous Asia I and the exotic biotype-B population from South India were used to carry out transmission experiments using Tomato leaf curl Bangalore virus(ToLCBV).The acquisition access periods(AAP),inoculation access periods(IAP),latent periods(LP),and ToLCBV transmission efficiencies of the two populations were compared and the biotype-B had the more efficient transmission characteristics.These results are discussed in relation to recent changes in the epidemiology of tomato leaf curl disease in South India.展开更多
Thermal adaptation plays a fundamental role in shaping the distribution and abundance of insects,and heat shock proteins(Hsps)play important roles in the temperature adaptation of various organisms.To better understan...Thermal adaptation plays a fundamental role in shaping the distribution and abundance of insects,and heat shock proteins(Hsps)play important roles in the temperature adaptation of various organisms.To better understand the temperature tolerance of the indigenous ZHJ2-biotype of whitefly Bemisia tabaci species complex,we obtained complete cDNA sequences for hsp90,hsp70,and hsp20 and analyzed their expression profiles under different high temperature treatments by real-time quantitative polymerase chain reaction.The high temperature tolerance of B.tabaci ZHJ2-biotype was determined by survival rate after exposure to different high temperatures for 1 h.The results showed that after 41°C heat-shock treatment for 1 h,the survival rates of ZHJ2 adults declined significantly and the estimated temperature required to cause 50% mortality(LT50)is 42.85°C for 1 h.Temperatures for onset(Ton)or maximal(Tmax)induction of hsps expression in B.tabaci ZHJ2-biotype were 35 and 39°C(or 41°C).Compared with previous studies,indigenous ZHJ2-biotype exhibits lower heat temperature stress tolerance and Ton(or Tmax)than the invasive B-biotype.展开更多
Cold stress responses help insects to survive under low temperatures that would be lethal otherwise.This phenomenon might contribute to the invasion of some Bemisia tabaci cryptic species from subtropical areas to tem...Cold stress responses help insects to survive under low temperatures that would be lethal otherwise.This phenomenon might contribute to the invasion of some Bemisia tabaci cryptic species from subtropical areas to temperate regions.However,the molecular mechanisms regulating cold stress responses in whitefly are yet unclear.Mitogen-activated protein kinases(MAPKs)which including p38,ERK,and JNK,are well known for their roles in regulating metabolic responses to cold stress in many insects.In this study,we explored the possible roles of the MAPKs in response to low temperature stresses in the Mediterranean cryptic species(the Q-biotype)of the B.tabaci species complex.First,we cloned the p38 and ERK genes from the whitefly cDNA library.Next,we analyzed the activation of MAPKs during cold stress in the Mediterranean cryptic species by immuno-blotting.After cold stress,the level of phospho-p38 increased but no significant change was observed in the phosphorylation of ERK and JNK,thus suggesting that the p38 might be responsible for the defense response to low temperature stress.Furthermore,we demonstrated that:i)3 min chilling at 0°C was sufficient for the activation of p38 MAPK pathway in this whitefly;and ii)the amount of phosphorylated p38 increased significantly in the first 20 min of chilling,reversed by 60 min,and then returned to the original level by 120 min.Taken together,our results suggest that the p38 pathway is important during response to low temperature stress in the Mediterranean cryptic species of the B.tabaci species complex.展开更多
The Bemisia tabaci(Gennadius)cryptic species complex comprises important insect pests that cause devastating damage to agricultural crops worldwide.In China,the B.tabaci Mediterranean(MED)(or biotype Q)species is thre...The Bemisia tabaci(Gennadius)cryptic species complex comprises important insect pests that cause devastating damage to agricultural crops worldwide.In China,the B.tabaci Mediterranean(MED)(or biotype Q)species is threatening agricultural production all over the country as resistance to commonly used insecticides has increased.This situation highlights the need for alternative pest control measures.Cyantraniliprole,a novel anthranilic diamide insecticide,has been widely employed to control Hemipteran pests.To monitor the levels of resistance to cyantraniliprole in B.tabaci field populations in China,bioassays were conducted for 18 field samples from nine provinces over two years.Compared with median lethal concentration(LC_(50))for the MED susceptible strain,all field samples had significantly higher resistance to cyantraniliprole.Furthermore,resistance factors(RFs)increased significantly in samples from Shanxi(from 5.62 in 2015 to 25.81 in 2016),Hunan(3.30 in 2015 to 20.97 in 2016)and Hubei(from 9.81 in 2015 to 23.91 in 2016)provinces.This study indicates a considerable decrease in the efficacy of cyantraniliprole against B.tabaci and establishes a baseline of susceptibility that could serve as a reference for future monitoring and management of B.tabaci resistance to cyantraniliprole.展开更多
The sweetpotato whitefly Bemisia tabaci(Hemiptera:Aleyrodidae)is an extremely polyphagous insect pest that causes significant crop losses in Israel and worldwide.B.tabaci is a species complex of which the B and Q biot...The sweetpotato whitefly Bemisia tabaci(Hemiptera:Aleyrodidae)is an extremely polyphagous insect pest that causes significant crop losses in Israel and worldwide.B.tabaci is a species complex of which the B and Q biotypes are the most widespread and damaging worldwide.The change in biotype composition and resistance to insecticide in Israel was monitored during the years 2008-2010 to identify patterns in population dynamics that can be correlated with resistance outbreaks.The results show that B biotype populations dominate crops grown in open fields,while Q biotype populations gradually dominate crops grown in protected conditions such as greenhouses and nethouses,where resistance outbreaks usually develop after several insecticide applications.While in previous years,Q biotype populations were widely detected in many regions in Israel,significant domination of the B biotype across populations collected was observed during the year 2010,indicating the instability of the B.tabaci population from one year to another.Reasons for the changing dynamics and the shift in the relative abundance of B.tabaci biotype,and their resistance status,are discussed.展开更多
A programme of functional genomics research is underway at the University of Greenwich,UK,to develop and apply genomics technologies to characterise an economically-important but under-researched Bemisia tabaci(Hemipt...A programme of functional genomics research is underway at the University of Greenwich,UK,to develop and apply genomics technologies to characterise an economically-important but under-researched Bemisia tabaci(Hemiptera:Aleyrodidae),the Asia 1 mtCOI phylogenetic group.A comparison of this putative species from India with other important B.tabaci populations and insect species may provide targets for the development of more effective whitefly control strategies.As a first step,next-generation sequencing(NGS)has been used to survey the transcriptome of adult female whitefly,with high quality RNA preparations being used to generate cDNA libraries for NGS using the Roche 454 Titanium DNA sequencing platform.Contig assemblies constructed from the resultant sequences(301 094 reads)using the software program CLC Genomics Workbench generated 3 821 core contigs.Comparison of a selection of these contigs with related sequences from other B.tabaci genetic groups has revealed good alignment for some genes(e.g.,HSP90)but misassemblies in other datasets(e.g.,the vitellogenin gene family),highlighting the need for manual curation as well as collaborative international efforts to obtain accurate assemblies from the existing next generation sequence datasets.Nevertheless,data emerging from the NGS has facilitated the development of accurate and reliable methods for analysing gene expression based on quantitative real-time RT-PCR,illustrating the power of this approach to enable rapid expression analyses in an organism for which a complete genome sequence is currently lacking.展开更多
Plant viruses in the families Luteoviridae and Geminiviridae are phloem restricted and are transmitted in a persistent,circulative manner by homopteran insects.Using fluorescence 2-D difference gel electrophoresis to ...Plant viruses in the families Luteoviridae and Geminiviridae are phloem restricted and are transmitted in a persistent,circulative manner by homopteran insects.Using fluorescence 2-D difference gel electrophoresis to compare the proteomes of F2 genotypes of Schizaphis graminum segregating for virus transmission ability,we recently discovered a panel of protein biomarkers that predict vector competency.Here we used aphid and whitefly nucleotide and expressed sequence tag database mining to test whether these biomarkers are conserved in other homopteran insects.S.graminum gene homologs that shared a high degree of predicted amino acid identity were discovered in two other aphid species and in the whitefly Bemisia tabaci.Selected reaction monitoring mass spectrometry was used to validate the expression of these biomarkers proteins in multiple aphid vector species.The conservation of these proteins in multiple insect taxa that transmit plant viruses along the circulative transmission pathway creates the opportunity to use these biomarkers to rapidly identify insect populations that are the most efficient vectors and allow them to be targeted for control prior to the spread of virus within a crop.展开更多
The whitefly Bemisia tabaci species complex and the begomoviruses they transmit are devastating agricultural pests worldwide.With the rapid and further inva-sions by some members of the whitefly species complex into n...The whitefly Bemisia tabaci species complex and the begomoviruses they transmit are devastating agricultural pests worldwide.With the rapid and further inva-sions by some members of the whitefly species complex into new regions,their impacts on human society are likely to increase in the years to come. This special issue of the Journal of Integrative Agriculture展开更多
The sweetpotato whitefly Bemisia tabaci(Homoptera:Aleyrodidae)is a destructive pest of agriculture and horticulture worldwide.Recent phylogenetic analysis using mitochondrial cytochrome oxidase 1 sequences indicates t...The sweetpotato whitefly Bemisia tabaci(Homoptera:Aleyrodidae)is a destructive pest of agriculture and horticulture worldwide.Recent phylogenetic analysis using mitochondrial cytochrome oxidase 1 sequences indicates that this whitefly is a species complex including at least 24 morphologically indistinguishable but genetically distinct cryptic species.In this study,the inter-species crosses of Middle East-Asia Minor 1(MEAM1),Mediterranean(MED)and Asia II 7 cryptic species,which were referred to as B,Q and Cv biotypes before,were conducted in two different devices,leaf cages(7 cm3)and cylinder cages(280 cm3),and at three temperatures of 22,30 and 38°C.Results indicated that no female progeny were produced in the reciprocal cross between MEAM1×Asia II 7,between MED×Asia II 7 cryptic species neither in leaf cage nor in cylinder cages,while 0.81 and 1.37% of females in the offspring were recorded in the reciprocal cross between MEAM1×MED in leaf cage experiments.Approximately 0.95-0.98% female progeny were recorded in the reciprocal cross between MEAM1×MED at 30°C,0.77% female progeny were recorded in the single cross direction between MEAM1 × MED at 22°C,and no female progeny were found in their reciprocal cross at 38°C in leaf cage.Our findings indicated that neither space dimension nor temperature have a significant effect on the hybridization of different B.tabaci cryptic species.展开更多
Flupyradifurone is a promising new insecticide used for controlling Bemisia tabaci during vegetable production.In this study,we assessed the fitness costs and mode of inheritance associated with resistance to flupyrad...Flupyradifurone is a promising new insecticide used for controlling Bemisia tabaci during vegetable production.In this study,we assessed the fitness costs and mode of inheritance associated with resistance to flupyradifurone in B.tabaci by comparing the susceptible strain(MED-S)to one field-evolved flupyradifurone-resistant strain(WH-R,with 199-fold resistance)and one laboratory-selected flupyradifurone-resistant strain(FLU-SEL,with 124-fold resistance).Progenies of reciprocal crosses between WH-R and MED-S(F_(1A),F_(1B),and pooled F_(1)),and between FLU-SEL and MED-S(F_(1C),F_(1D),and pooled F_(1)’),showed varying degrees of dominance,indicating that resistance to flupyradifurone in WH-R was autosomal and incompletely dominant,yet in FLU-SEL it was autosomal and incompletely recessive.Furthermore,the development of resistance to flupyradifurone occurred at the expense of fitness costs for the resistant populations.Compared to the MED-S strain,WH-R showed a relative fitness of 0.50 with significantly prolonged developmental durations and reduced survival rates of the nymphal and pseudopupal stages,as well as decreased fecundity and hatchability.Similarly,FLU-SEL showed a relative fitness of 0.65 and also demonstrated prolonged developmental durations and reduced survival rates of nymphs and pseudopupae,as well as decreased hatchability in comparison with the MED-S strain.However,no significant differences in fecundity were observed between MED-S and FLU-SEL.The present study provides useful knowledge for formulating pest management strategies in the field,which will allow growers to slow the development of resistance to flupyradifurone and to sustainably control B.tabaci.展开更多
Insects are poikilothermic animals,and temperature is one of the most important abiotic factors affecting their spread and distribution.For example,differences in thermal tolerance may underlie the significant differe...Insects are poikilothermic animals,and temperature is one of the most important abiotic factors affecting their spread and distribution.For example,differences in thermal tolerance may underlie the significant differences in geographical distributions between the native AsiaII3 and invasive MED(Mediterranean)cryptic Bemisia tabaci species in China.Transient receptor potential(TRP)channels are key components of the insect temperature perception system and act as molecular thermometers since they can be activated by specific changes in temperature.In this study,we cloned and characterized the AsiaII3 BtTRP gene and revealed its functions in the response to thermal stress.The full-length cDNA of BtTRP was 3821 bp,with a 3501-bp open reading frame encoding a 132.05-kDa protein.Comparing the deduced amino acid sequences of AsiaII3 BtTRP and MED TRP revealed five amino acid differences.In situ hybridization indicated that BtTRP might be widely expressed throughout the AsiaII3 adult body.BtTRP mRNA expression reached the highest levels after exposure to mild thermal stimuli(12 and 35°C),showing that BtTRP expression can be induced by temperature stress.Furthermore,the thermal tolerance of AsiaII3 after BtTRP dsRNA feeding was significantly lower than that of the control.Taken together,the present study highlights the importance of TRP channels for B.tabaci thermal resistance,and allows us to infer that the differences in amino acids between AsiaII3 and MED might cause the differences in thermal tolerance of these two cryptic species.This study provides a new direction for investigating geographic distribution differences between invasive and native insects.展开更多
The development of plant-derived products to control Bemisia tabaci Genn.(Hemiptera:Aleyrodidae)is an urgent need for production of horticultural crops.Plant extracts and essential oils of several species of the genus...The development of plant-derived products to control Bemisia tabaci Genn.(Hemiptera:Aleyrodidae)is an urgent need for production of horticultural crops.Plant extracts and essential oils of several species of the genus Eugenia(Myrtaceae)have shown insecticidal activity.In southern Mexico,leaf extracts from Eugenia winzerlingii showed nematicidal effect but its insecticidal properties have not been explored.Therefore,the objective of this study was to evaluate the insecticidal effect of aqueous and organic extracts from E.winzerlingii leaves on B.tabaci egg,nymph and adult stages,and else to explore its nursery propagation.Then,extracts of this species were obtained by maceration with different polarity solvents.Bioassays were carried out on Capsicum chinense leaves.Mortality assays showed that aqueous and total crude ethanol(TCE)extracts necrosed the eggs(LC50=0.21%w/v and 4.68 mg/mL,respectively),whereas hexane,ethyl acetate(ETA),residual ethanol and TCE extracts affected the nymphs(LC50=0.25-4.85 mg/mL).In adults,oviposition inhibition by free choice assay indicated that TCE and ETA extracts had major activity(EC50=14.62 and 27.86μg/cm2,respectively).On other hand,the sexual and vegetative propagation of E.winzerlingii showed that this species can be easily cultivated by seeds.In conclusion,extracts of E.winzerlingii leaves are highly effective in controlling B.tabaci.TCE extract,in particular,was toxic to three stages of B.tabaci.This plant could be a potential alternative to develop a novel botanical insecticide to manage this destructive pest.展开更多
基金funded by the National Basic Research and Development Program ofChina(2009CB119200)the National Natural Science Foundation of China(31071683)the Earmarked Fund forModern Agro-Industry Technology Research System,China(CARS-27)
文摘The whitefly Bemisia tabaci are considered as a taxonomically complex that contained some destructive pests.Two of the most prevalent cryptic species are B.tabaci Middle East-Asia Minor 1(MEAM1)and Mediterranean(MED).In an extensive field survey of the B.tabaci complex present throughout part of China from 2004 to 2007,we obtained 93 samples of B.tabaci from 22 provinces.We determined that these Chinese haplotypes included 2 invasive species(MEAM1 and MED),and 4 indigenous cryptic species(Asia II 1,Asia II 3,China 3 and Asia II 7)by sequencing mitochondrial cytochrome oxidose one gene(mtCOI).The diversity and genetic differentiation of a subset of 19 populations of B.tabaci were studied using cDNA amplified fragment length polymorphism(AFLP).Prior to 2007,MEAM1 was a dominant species in many provinces in China.By 2007,MED was dominant in 11 provinces.Both invasive and indigenous species were simultaneously found in some regions.Indigenous species of B.tabaci were found in six provinces in southern China.MED and MEAM1 have broad ranges of host plants,and indigenous species appeared to have much narrower host ranges.All Asia II 3 samples were found on cotton except one on aubergine.China 3 has more host plants than Asia II 3.Twelve samples of China 3 were collected from sweet potato,Japanese hop,squash and cotton.A total of 677 reproducible bands amplified with 5 AFLP primer combinations were obtained.The highest proportion of polymorphic bands was 98.7% and the lowest was 91.9%.Unweighted pair-group method analysis indicated that the clustering was independent of the different species.MED showed the lowest degree of similarity than the other species.The data indicate that both MEAM1and MED were rapidly established in China.
基金R.V.Chowda-Reddy(HEFCE fellowship)and Kiran Kumar,from the research projects funded by the University of Greenwich,together with the Department for International Development,UK(DFID project code R8247,Crop Protection Programme)
文摘Bemisia tabaci adults from various host-plant species were collected from 31 regions across India.266 B.tabaci samples were first screened by RAPD-PCR to examine molecular variability and to select individuals with different fingerprints.Host-plant and region of collection were then used to select 25 individuals for PCR amplification and sequencing of their partial mitochondrial cytochrome oxidase subunit one(mtCOI)genes.Pairwise comparisons with mtCOI consensus sequences showed that the majority of these samples had <3.5% sequence divergence from groups currently termed Asia I,Asia II-5,Asia II-7,and Asia II-8.The biotype-B B.tabaci from India clustered into the Middle East-Asia Minor 1 group.A new group of B.tabaci from Coimbatore,collected from pumpkin,was related most closely to the Asia I group(6.2% sequence divergence from the consensus Asia I sequence).To increase our understanding of the epidemiology of tomato leaf curl disease(ToLCD)and the key B.tabaci genetic groups involved in virus spread,the indigenous Asia I and the exotic biotype-B population from South India were used to carry out transmission experiments using Tomato leaf curl Bangalore virus(ToLCBV).The acquisition access periods(AAP),inoculation access periods(IAP),latent periods(LP),and ToLCBV transmission efficiencies of the two populations were compared and the biotype-B had the more efficient transmission characteristics.These results are discussed in relation to recent changes in the epidemiology of tomato leaf curl disease in South India.
基金supported by the National Basic R&D Program of China(2009CB119200)the National Natural Science Foundation of China(30800722)
文摘Thermal adaptation plays a fundamental role in shaping the distribution and abundance of insects,and heat shock proteins(Hsps)play important roles in the temperature adaptation of various organisms.To better understand the temperature tolerance of the indigenous ZHJ2-biotype of whitefly Bemisia tabaci species complex,we obtained complete cDNA sequences for hsp90,hsp70,and hsp20 and analyzed their expression profiles under different high temperature treatments by real-time quantitative polymerase chain reaction.The high temperature tolerance of B.tabaci ZHJ2-biotype was determined by survival rate after exposure to different high temperatures for 1 h.The results showed that after 41°C heat-shock treatment for 1 h,the survival rates of ZHJ2 adults declined significantly and the estimated temperature required to cause 50% mortality(LT50)is 42.85°C for 1 h.Temperatures for onset(Ton)or maximal(Tmax)induction of hsps expression in B.tabaci ZHJ2-biotype were 35 and 39°C(or 41°C).Compared with previous studies,indigenous ZHJ2-biotype exhibits lower heat temperature stress tolerance and Ton(or Tmax)than the invasive B-biotype.
基金supported by the National Natural Science Foundation of China(30730061)the National Basic Research Program of China(2009CB119203)
文摘Cold stress responses help insects to survive under low temperatures that would be lethal otherwise.This phenomenon might contribute to the invasion of some Bemisia tabaci cryptic species from subtropical areas to temperate regions.However,the molecular mechanisms regulating cold stress responses in whitefly are yet unclear.Mitogen-activated protein kinases(MAPKs)which including p38,ERK,and JNK,are well known for their roles in regulating metabolic responses to cold stress in many insects.In this study,we explored the possible roles of the MAPKs in response to low temperature stresses in the Mediterranean cryptic species(the Q-biotype)of the B.tabaci species complex.First,we cloned the p38 and ERK genes from the whitefly cDNA library.Next,we analyzed the activation of MAPKs during cold stress in the Mediterranean cryptic species by immuno-blotting.After cold stress,the level of phospho-p38 increased but no significant change was observed in the phosphorylation of ERK and JNK,thus suggesting that the p38 might be responsible for the defense response to low temperature stress.Furthermore,we demonstrated that:i)3 min chilling at 0°C was sufficient for the activation of p38 MAPK pathway in this whitefly;and ii)the amount of phosphorylated p38 increased significantly in the first 20 min of chilling,reversed by 60 min,and then returned to the original level by 120 min.Taken together,our results suggest that the p38 pathway is important during response to low temperature stress in the Mediterranean cryptic species of the B.tabaci species complex.
基金supported by the National Natural Science Foundation of China (31601635)the Beijing Natural Science Foundation,China (6174038)the earmarked fund for Beijing Innovation Consortium of Agriculture Research System,China (BAIC07-2017)
文摘The Bemisia tabaci(Gennadius)cryptic species complex comprises important insect pests that cause devastating damage to agricultural crops worldwide.In China,the B.tabaci Mediterranean(MED)(or biotype Q)species is threatening agricultural production all over the country as resistance to commonly used insecticides has increased.This situation highlights the need for alternative pest control measures.Cyantraniliprole,a novel anthranilic diamide insecticide,has been widely employed to control Hemipteran pests.To monitor the levels of resistance to cyantraniliprole in B.tabaci field populations in China,bioassays were conducted for 18 field samples from nine provinces over two years.Compared with median lethal concentration(LC_(50))for the MED susceptible strain,all field samples had significantly higher resistance to cyantraniliprole.Furthermore,resistance factors(RFs)increased significantly in samples from Shanxi(from 5.62 in 2015 to 25.81 in 2016),Hunan(3.30 in 2015 to 20.97 in 2016)and Hubei(from 9.81 in 2015 to 23.91 in 2016)provinces.This study indicates a considerable decrease in the efficacy of cyantraniliprole against B.tabaci and establishes a baseline of susceptibility that could serve as a reference for future monitoring and management of B.tabaci resistance to cyantraniliprole.
基金This is contribution No.503/11 from the Agricultural Research Organization,the Volcani Center,Bet Dagan,Israel
文摘The sweetpotato whitefly Bemisia tabaci(Hemiptera:Aleyrodidae)is an extremely polyphagous insect pest that causes significant crop losses in Israel and worldwide.B.tabaci is a species complex of which the B and Q biotypes are the most widespread and damaging worldwide.The change in biotype composition and resistance to insecticide in Israel was monitored during the years 2008-2010 to identify patterns in population dynamics that can be correlated with resistance outbreaks.The results show that B biotype populations dominate crops grown in open fields,while Q biotype populations gradually dominate crops grown in protected conditions such as greenhouses and nethouses,where resistance outbreaks usually develop after several insecticide applications.While in previous years,Q biotype populations were widely detected in many regions in Israel,significant domination of the B biotype across populations collected was observed during the year 2010,indicating the instability of the B.tabaci population from one year to another.Reasons for the changing dynamics and the shift in the relative abundance of B.tabaci biotype,and their resistance status,are discussed.
基金Funding for the studies described was provided by the University of Greenwich Proof of Concept and Research Funds,UK(E0162/RAE-NRI-009/09and K0070)
文摘A programme of functional genomics research is underway at the University of Greenwich,UK,to develop and apply genomics technologies to characterise an economically-important but under-researched Bemisia tabaci(Hemiptera:Aleyrodidae),the Asia 1 mtCOI phylogenetic group.A comparison of this putative species from India with other important B.tabaci populations and insect species may provide targets for the development of more effective whitefly control strategies.As a first step,next-generation sequencing(NGS)has been used to survey the transcriptome of adult female whitefly,with high quality RNA preparations being used to generate cDNA libraries for NGS using the Roche 454 Titanium DNA sequencing platform.Contig assemblies constructed from the resultant sequences(301 094 reads)using the software program CLC Genomics Workbench generated 3 821 core contigs.Comparison of a selection of these contigs with related sequences from other B.tabaci genetic groups has revealed good alignment for some genes(e.g.,HSP90)but misassemblies in other datasets(e.g.,the vitellogenin gene family),highlighting the need for manual curation as well as collaborative international efforts to obtain accurate assemblies from the existing next generation sequence datasets.Nevertheless,data emerging from the NGS has facilitated the development of accurate and reliable methods for analysing gene expression based on quantitative real-time RT-PCR,illustrating the power of this approach to enable rapid expression analyses in an organism for which a complete genome sequence is currently lacking.
基金supported by NSF BREAD IOS:1109989,USDA-NRI 2007-04567,NSFDBI-0606596USDA-ARS 764 CRIS projects1907-101-16,1907-21000-024/25-00DNIH/NCRR funded Yeast Resource Center P41RR01182
文摘Plant viruses in the families Luteoviridae and Geminiviridae are phloem restricted and are transmitted in a persistent,circulative manner by homopteran insects.Using fluorescence 2-D difference gel electrophoresis to compare the proteomes of F2 genotypes of Schizaphis graminum segregating for virus transmission ability,we recently discovered a panel of protein biomarkers that predict vector competency.Here we used aphid and whitefly nucleotide and expressed sequence tag database mining to test whether these biomarkers are conserved in other homopteran insects.S.graminum gene homologs that shared a high degree of predicted amino acid identity were discovered in two other aphid species and in the whitefly Bemisia tabaci.Selected reaction monitoring mass spectrometry was used to validate the expression of these biomarkers proteins in multiple aphid vector species.The conservation of these proteins in multiple insect taxa that transmit plant viruses along the circulative transmission pathway creates the opportunity to use these biomarkers to rapidly identify insect populations that are the most efficient vectors and allow them to be targeted for control prior to the spread of virus within a crop.
基金the National Natural Science Foundation of China(projects30730061 and 31021003)the National Basic Research Programme of China(2009CB119203)for support to the International Symposium on Future Directions in Bemisia Research held in Hangzhou and thepublication of this special issue
文摘The whitefly Bemisia tabaci species complex and the begomoviruses they transmit are devastating agricultural pests worldwide.With the rapid and further inva-sions by some members of the whitefly species complex into new regions,their impacts on human society are likely to increase in the years to come. This special issue of the Journal of Integrative Agriculture
基金funded by the National Basic Research Program of China(2009CB119203)the National NaturalScience Foundation of China(31071732)the Foundation of Lingnan Fruit Innovation Team of GuangdongProvince,China(2009-14)
文摘The sweetpotato whitefly Bemisia tabaci(Homoptera:Aleyrodidae)is a destructive pest of agriculture and horticulture worldwide.Recent phylogenetic analysis using mitochondrial cytochrome oxidase 1 sequences indicates that this whitefly is a species complex including at least 24 morphologically indistinguishable but genetically distinct cryptic species.In this study,the inter-species crosses of Middle East-Asia Minor 1(MEAM1),Mediterranean(MED)and Asia II 7 cryptic species,which were referred to as B,Q and Cv biotypes before,were conducted in two different devices,leaf cages(7 cm3)and cylinder cages(280 cm3),and at three temperatures of 22,30 and 38°C.Results indicated that no female progeny were produced in the reciprocal cross between MEAM1×Asia II 7,between MED×Asia II 7 cryptic species neither in leaf cage nor in cylinder cages,while 0.81 and 1.37% of females in the offspring were recorded in the reciprocal cross between MEAM1×MED in leaf cage experiments.Approximately 0.95-0.98% female progeny were recorded in the reciprocal cross between MEAM1×MED at 30°C,0.77% female progeny were recorded in the single cross direction between MEAM1 × MED at 22°C,and no female progeny were found in their reciprocal cross at 38°C in leaf cage.Our findings indicated that neither space dimension nor temperature have a significant effect on the hybridization of different B.tabaci cryptic species.
基金supported by research grants from the National Natural Science Foundation of China(31972266)。
文摘Flupyradifurone is a promising new insecticide used for controlling Bemisia tabaci during vegetable production.In this study,we assessed the fitness costs and mode of inheritance associated with resistance to flupyradifurone in B.tabaci by comparing the susceptible strain(MED-S)to one field-evolved flupyradifurone-resistant strain(WH-R,with 199-fold resistance)and one laboratory-selected flupyradifurone-resistant strain(FLU-SEL,with 124-fold resistance).Progenies of reciprocal crosses between WH-R and MED-S(F_(1A),F_(1B),and pooled F_(1)),and between FLU-SEL and MED-S(F_(1C),F_(1D),and pooled F_(1)’),showed varying degrees of dominance,indicating that resistance to flupyradifurone in WH-R was autosomal and incompletely dominant,yet in FLU-SEL it was autosomal and incompletely recessive.Furthermore,the development of resistance to flupyradifurone occurred at the expense of fitness costs for the resistant populations.Compared to the MED-S strain,WH-R showed a relative fitness of 0.50 with significantly prolonged developmental durations and reduced survival rates of the nymphal and pseudopupal stages,as well as decreased fecundity and hatchability.Similarly,FLU-SEL showed a relative fitness of 0.65 and also demonstrated prolonged developmental durations and reduced survival rates of nymphs and pseudopupae,as well as decreased hatchability in comparison with the MED-S strain.However,no significant differences in fecundity were observed between MED-S and FLU-SEL.The present study provides useful knowledge for formulating pest management strategies in the field,which will allow growers to slow the development of resistance to flupyradifurone and to sustainably control B.tabaci.
基金This work was funded by the National Natural Science Foundation of China(31672088 and 31601695)the Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences(caascx-2017-2022-IAS)the National Key Research and Development Program of China(2016YFC1200603).
文摘Insects are poikilothermic animals,and temperature is one of the most important abiotic factors affecting their spread and distribution.For example,differences in thermal tolerance may underlie the significant differences in geographical distributions between the native AsiaII3 and invasive MED(Mediterranean)cryptic Bemisia tabaci species in China.Transient receptor potential(TRP)channels are key components of the insect temperature perception system and act as molecular thermometers since they can be activated by specific changes in temperature.In this study,we cloned and characterized the AsiaII3 BtTRP gene and revealed its functions in the response to thermal stress.The full-length cDNA of BtTRP was 3821 bp,with a 3501-bp open reading frame encoding a 132.05-kDa protein.Comparing the deduced amino acid sequences of AsiaII3 BtTRP and MED TRP revealed five amino acid differences.In situ hybridization indicated that BtTRP might be widely expressed throughout the AsiaII3 adult body.BtTRP mRNA expression reached the highest levels after exposure to mild thermal stimuli(12 and 35°C),showing that BtTRP expression can be induced by temperature stress.Furthermore,the thermal tolerance of AsiaII3 after BtTRP dsRNA feeding was significantly lower than that of the control.Taken together,the present study highlights the importance of TRP channels for B.tabaci thermal resistance,and allows us to infer that the differences in amino acids between AsiaII3 and MED might cause the differences in thermal tolerance of these two cryptic species.This study provides a new direction for investigating geographic distribution differences between invasive and native insects.
文摘The development of plant-derived products to control Bemisia tabaci Genn.(Hemiptera:Aleyrodidae)is an urgent need for production of horticultural crops.Plant extracts and essential oils of several species of the genus Eugenia(Myrtaceae)have shown insecticidal activity.In southern Mexico,leaf extracts from Eugenia winzerlingii showed nematicidal effect but its insecticidal properties have not been explored.Therefore,the objective of this study was to evaluate the insecticidal effect of aqueous and organic extracts from E.winzerlingii leaves on B.tabaci egg,nymph and adult stages,and else to explore its nursery propagation.Then,extracts of this species were obtained by maceration with different polarity solvents.Bioassays were carried out on Capsicum chinense leaves.Mortality assays showed that aqueous and total crude ethanol(TCE)extracts necrosed the eggs(LC50=0.21%w/v and 4.68 mg/mL,respectively),whereas hexane,ethyl acetate(ETA),residual ethanol and TCE extracts affected the nymphs(LC50=0.25-4.85 mg/mL).In adults,oviposition inhibition by free choice assay indicated that TCE and ETA extracts had major activity(EC50=14.62 and 27.86μg/cm2,respectively).On other hand,the sexual and vegetative propagation of E.winzerlingii showed that this species can be easily cultivated by seeds.In conclusion,extracts of E.winzerlingii leaves are highly effective in controlling B.tabaci.TCE extract,in particular,was toxic to three stages of B.tabaci.This plant could be a potential alternative to develop a novel botanical insecticide to manage this destructive pest.