Communities of bacteria,especially symbionts,are vital for the growth and development of insects and other arthropods,including Bemisia tabaci Mediterranean(MED),a destructive and invasive insect pest.However,the infe...Communities of bacteria,especially symbionts,are vital for the growth and development of insects and other arthropods,including Bemisia tabaci Mediterranean(MED),a destructive and invasive insect pest.However,the infection density patterns and influence factors of bacteria in whiteflies,which mainly include symbionts,remain largely unclear.To reveal the different density patterns of Cardinium in B.tabaci MED popula-tions and the impacts of high temperatures on whiteflies with different Cardinium density infection patterns,2 isofemale lines isolated from B.tabaci MED from the same geo-graphical population of China and from B.tabaci MED collected from other countries and locations were examined using several techniques and methods,including fluorescence in situ hybridization(FISH),quantitative real-time polymerase chain reaction(qPCR),16S rRNA gene sequencing,and 2b-RAD sequencing.The results showed that there were 2 different infection density patterns of Cardinium in B.tabaci MED(including 1 high-density pattern and 1 low-density pattern).For whiteflies with low-density Cardinium,conventional PCR could not detect Cardinium,but the other techniques confirmed that there was a low level of Cardinium within hosts.High temperature significantly decreased the diversity of bacterial communities:the relative titer of Cardinium increased but the density of Rickettsia decreased in the isofemale line with high-density Cardinium.How-ever,high temperature did not influence the diversity and symbiont density in the line with low-density Cardinium.Moreover,high temperature influenced the functions of bacterial communities in whiteflies with high-density Cardinium but did not affect the bacterial functions in whiteflies with low-density Cardinium.Our results provide novel insights into the complex associations between symbionts and host insects.展开更多
Odorant-binding proteins (OBPs) and chemosensory proteins (CSPs) of insects are thought to play roles in olfactory recognition affecting host choice, copulation, reproduction and other behaviors. Previous descriptions...Odorant-binding proteins (OBPs) and chemosensory proteins (CSPs) of insects are thought to play roles in olfactory recognition affecting host choice, copulation, reproduction and other behaviors. Previous descriptions of OBPs and CSPs in the whitefly Bemisia tabaci often provided no or incomplete genetic information. In this study, we present a genome-wide and transcriptome-wide investigation of the OBPs and CSPs in B. tabaci MEAMl (Middle East-Asia Minorl species). Eight OBP and 19 CSP genes were identified that covered all previous sequences. Phylogenetic analyses showed that the CSP genes had a lineage-specific expansion (BtabBCSP人 BtabBCSP3, BtabBCSPl3, BtabBCSPl 7, BtabBCSP18 and BtabBCSP 19). Expression profiling of OBPs and CSPs by transcriptome sequencing and quantitative real-time polymerase chain reaction (qPCR) revealed that expression patterns differed among developmental stages of B. tabaci MEAM 1. Five OBP genes and 11 CSP genes significantly differed between males and females;four of the 19 CSP genes were highly expressed in adults, while two were highly expressed in nymphs. The expression profiles of the OBP and CSP genes in different tissues of B. tabaci MEAM1 adults were analyzed by qPCR. Four OBP genes found in B. tabaci MEAM 1 were highly expressed in the head. Conversely, only two CSPs were enriched in the head, while the other six CSPs were specifically expressed in other tissues. Our results provide a foundation for future research on OBPs and CSPs in B. tabaci.展开更多
Bemisia tabaci shifted unexpectedly in China from a predominance of B biotype to Q biotype during 2005-2008. This observation stimulated an interest in inves- tigating whether environmental factors, including host, te...Bemisia tabaci shifted unexpectedly in China from a predominance of B biotype to Q biotype during 2005-2008. This observation stimulated an interest in inves- tigating whether environmental factors, including host, temperature and relative humidity (RH) could possibly explain the observed shift in biotypes distribution. Results indicated that all three parameters examined influenced biotype survivability. The percentage of B biotype, when reared together on pepper plants with the Q biotype, decreased significantly from 66.7% in the founder population, to 13.6% and 3.7% in the first and second genera- tions, respectively. When the B (founder at 66.7%) and Q (founder at 33.3%) biotypes were reared together on eggplant alone, or on pepper-plus-eggplant combination, the population size of the B biotype either remained constant, or increased somewhat in the first and sec- ond generations. On eggplant, the effects of RH and temperature on the competitiveness between the Q and B biotypes (3 pairs of Q and 6 pairs of B) were not significant.展开更多
Field trials were conducted in China in 2008 and 2009 to evaluate the efficacy of mating disruption (MD) on diamondback moth, Plutella xylostella, in cabbage, Brassica oleracea var. capitata. Effectiveness was posit...Field trials were conducted in China in 2008 and 2009 to evaluate the efficacy of mating disruption (MD) on diamondback moth, Plutella xylostella, in cabbage, Brassica oleracea var. capitata. Effectiveness was positively correlated with the MD dispenser density in the field. A density of 167 MD dispensers per ha produced an average population decrease of about 50% compared to the conventional-practice field. Significant fewer males were captured in pheromone-treated and conventional-practice fields than in the blank control field, but the difference was not significant between the pheromone-treated and conventional-practice fields. In addition, fewer eggs and larvae were observed in pheromone-treated fields. Our results suggest mating disruption coupled with minimal insecticidal supplements is a promising solution for resistance management and control of diamondback moth infestation.展开更多
RNA interference(RNAi)techniques have emerged as powerful tools that facilitate development of novel management strategies for insect pests,such as Henosepilachna vigintioctopunctata(Coleoptera:Coccinellidae),which is...RNA interference(RNAi)techniques have emerged as powerful tools that facilitate development of novel management strategies for insect pests,such as Henosepilachna vigintioctopunctata(Coleoptera:Coccinellidae),which is a major pest of solanaceous plants in Asia.In this study,the potential of oral delivery of in vvYro-synthesized and bacterially expressed double-stranded H.vigintioctopunctata lesswright(Iwr)gene(dsHvlwr)to manage of H.vigintioctopunctata was investigated.Our results showed that the gene Hvlwr had a 480-bp open reading frame and encoded a 160-amino acid protein.Hvlwr expression levels were greater in the fat body than other tissue types.Hvlwr silencing led to greater H.vigintioctopunctata mortality rates and appeared to be time-and partially dose-dependent,likely as a result of the number of hemocytes increasing with dsRNA concentration,but decreasing with time.Bacterially expressed dsHvlwr that was applied to leaf discs caused 88%,66%,and 36%mortality in 1st instars,3rd instars,and adults after 10,10,and 14 d,respectively;when applied to living plants,there was greater mortality in 1 st and 3rd instars,but there was no effect on adults.Furthermore,dsHvlwr led to improved plant protection against H.vigintioctopunctata.Our study shows an effective dietary RNAi response in H.vigintioctopunctata and that Hvlwr is a promising RNAi target gene for control of this pest species.展开更多
The invasive pest whitefly(Bemisia tabaci)is a complex species,of which Middle East-Minor Asia 1(MEAM1)and Mediterranean(MED)are the two most damaging members.Previous research showed that cabbage is frequently infest...The invasive pest whitefly(Bemisia tabaci)is a complex species,of which Middle East-Minor Asia 1(MEAM1)and Mediterranean(MED)are the two most damaging members.Previous research showed that cabbage is frequently infested with MEAM1 but seldomly with MED,and this difference in performance is associated with glucosi-nolate(GS)content.Some insects can modify GS using glucosinolate sulfatase(SULF),the activity of which is regulated by sulfatase modifying factor 1(SUMF1);therefore,to increase our understanding of different performances of MEAM1 and MED on cabbage plants,we identified and compared nine putative SULFs and one SUMF in MEAM1 and MED.We found that the lengths of two genes,BtSulf2 and BtSulf4,differed between MEAM1 and MED.The messenger RNA levels of BtSulf4 increased more than 20-fold after MEAMl and MED adults were exposed to GS,but BtSulJ2 expression was only induced by GS in MEAM1.Knockdown of BtSulf2 and BtSulf4 in MEAM1 resulted in a substantial increase in the mortality of GS-treated adults but not in MED.These results indicate that differences in BtSulJ2 and BtSulf4 sequences and/or expression may explain why MEAM1 performs better than MED on cabbage.Our results provide a basis for future functional research on SULF and SUMF in B.tabaci.展开更多
MEAMI(Middle East-Asia Minor 1."B"biotype)anpl MED(Mediterranean,"Q"biotype)are the two most destructive ery pie species of the Bemisia tabaci complex on the planet.Our previous studies have shown ...MEAMI(Middle East-Asia Minor 1."B"biotype)anpl MED(Mediterranean,"Q"biotype)are the two most destructive ery pie species of the Bemisia tabaci complex on the planet.Our previous studies have shown that MEAMI outcompets MED on cabbage;the underlying mechanism is unknown.In the Brassicaceae family,the glucosinolate-myrosinase defense system plays a crucial role im deterring feeding,inhibiting growth,and eausing acute toxicity against a wide range of generalist herbivores.In the present study.we first compared the surv ival of MEAMI and MED exposed to sinigin(a glucosinolate)and myosinase(an enzyme that degrades glucosinolates);we found that survival of both species was high in response 10 sinigrin alone bul was near zer0 in response to sinigrin+myrosinase.We then used electropenetrography(lectrical penetration graphs,EPG)to assess the feeding bchaviors of MEAMI and MED whiteflies on cabbage.The EPG results revealed that the me an dunution of each potential drop(pd,indicating an intreellular puncture)was subsantialy longer for MED than MEAMI on eabbage,indicating that the exposure to the toxic hydrolysates of glucosinolate and myrosinase is greater for MED than for MEAMI.We therefore conclude that dffreces in penetrating bchaviors may help explain the dfferent fiects of cabbuge on MEAMI and MED whitefly species.展开更多
Diamondback moth, Plutella xylostella (L.) is one of the most serious insect pests for its remarkable ability to develop resistance to virtually every insecticide that has been used against it. In the present study,...Diamondback moth, Plutella xylostella (L.) is one of the most serious insect pests for its remarkable ability to develop resistance to virtually every insecticide that has been used against it. In the present study, amplified fragment length poly- morphism (AFLP) is used to study the genetic differentiation as well as the effects of abamectin-selection on population genetic differentiation for P. xylostella. A dendrogram was constructed from the matrix of genetic distances using the STATISTICA software (Version 4.5) and unweighted pair-group method with arithmetic averages (UPGMA). The data demonstrated that compared to the susceptible strain (ABM-s), the heterozy- gosity in the abamectin-resistant strain (ABM-r) decreased with the increased selection pressure and resistant level. When the resistance ratio was below 4.3, there was no sig- nificant differentiation at the genome DNA level. When the resistance ratio reached 5.8, a fairly significant differentiation began to appear, and when the resistance ratio reached and exceeded 8.1, there appeared a significant genetic differentiation. The results suggest that abamectin selection is associated with increased genetic polymorphism in P. xylostella.展开更多
基金supported by the National Natural Science Foundation of China(31872030)the Taishan Scholar Foundation of Shandong Province of China,the First Class Grassland Science Discipline Program of Shandong Province,China,and the Qingdao Agricultural University High-level Talent Fund(663-1121025).
文摘Communities of bacteria,especially symbionts,are vital for the growth and development of insects and other arthropods,including Bemisia tabaci Mediterranean(MED),a destructive and invasive insect pest.However,the infection density patterns and influence factors of bacteria in whiteflies,which mainly include symbionts,remain largely unclear.To reveal the different density patterns of Cardinium in B.tabaci MED popula-tions and the impacts of high temperatures on whiteflies with different Cardinium density infection patterns,2 isofemale lines isolated from B.tabaci MED from the same geo-graphical population of China and from B.tabaci MED collected from other countries and locations were examined using several techniques and methods,including fluorescence in situ hybridization(FISH),quantitative real-time polymerase chain reaction(qPCR),16S rRNA gene sequencing,and 2b-RAD sequencing.The results showed that there were 2 different infection density patterns of Cardinium in B.tabaci MED(including 1 high-density pattern and 1 low-density pattern).For whiteflies with low-density Cardinium,conventional PCR could not detect Cardinium,but the other techniques confirmed that there was a low level of Cardinium within hosts.High temperature significantly decreased the diversity of bacterial communities:the relative titer of Cardinium increased but the density of Rickettsia decreased in the isofemale line with high-density Cardinium.How-ever,high temperature did not influence the diversity and symbiont density in the line with low-density Cardinium.Moreover,high temperature influenced the functions of bacterial communities in whiteflies with high-density Cardinium but did not affect the bacterial functions in whiteflies with low-density Cardinium.Our results provide novel insights into the complex associations between symbionts and host insects.
基金the National Natural Science Foundation of China (31420103919, 31672032 and 31772172)Beijing Nova Program (Z171100001117039)Science and Technology Innovation Project from the Chinese Academy of Agricultural Sciences (CAASXTCX2016017002)and the Beijing Key Laboratory for Pest Control and Sustainable Cultivation of Vegetables.
文摘Odorant-binding proteins (OBPs) and chemosensory proteins (CSPs) of insects are thought to play roles in olfactory recognition affecting host choice, copulation, reproduction and other behaviors. Previous descriptions of OBPs and CSPs in the whitefly Bemisia tabaci often provided no or incomplete genetic information. In this study, we present a genome-wide and transcriptome-wide investigation of the OBPs and CSPs in B. tabaci MEAMl (Middle East-Asia Minorl species). Eight OBP and 19 CSP genes were identified that covered all previous sequences. Phylogenetic analyses showed that the CSP genes had a lineage-specific expansion (BtabBCSP人 BtabBCSP3, BtabBCSPl3, BtabBCSPl 7, BtabBCSP18 and BtabBCSP 19). Expression profiling of OBPs and CSPs by transcriptome sequencing and quantitative real-time polymerase chain reaction (qPCR) revealed that expression patterns differed among developmental stages of B. tabaci MEAM 1. Five OBP genes and 11 CSP genes significantly differed between males and females;four of the 19 CSP genes were highly expressed in adults, while two were highly expressed in nymphs. The expression profiles of the OBP and CSP genes in different tissues of B. tabaci MEAM1 adults were analyzed by qPCR. Four OBP genes found in B. tabaci MEAM 1 were highly expressed in the head. Conversely, only two CSPs were enriched in the head, while the other six CSPs were specifically expressed in other tissues. Our results provide a foundation for future research on OBPs and CSPs in B. tabaci.
文摘Bemisia tabaci shifted unexpectedly in China from a predominance of B biotype to Q biotype during 2005-2008. This observation stimulated an interest in inves- tigating whether environmental factors, including host, temperature and relative humidity (RH) could possibly explain the observed shift in biotypes distribution. Results indicated that all three parameters examined influenced biotype survivability. The percentage of B biotype, when reared together on pepper plants with the Q biotype, decreased significantly from 66.7% in the founder population, to 13.6% and 3.7% in the first and second genera- tions, respectively. When the B (founder at 66.7%) and Q (founder at 33.3%) biotypes were reared together on eggplant alone, or on pepper-plus-eggplant combination, the population size of the B biotype either remained constant, or increased somewhat in the first and sec- ond generations. On eggplant, the effects of RH and temperature on the competitiveness between the Q and B biotypes (3 pairs of Q and 6 pairs of B) were not significant.
基金The authors would like to thank Prof. Anthony M. Shelton and Ms. Hilda L. Collins in Cornell University for review- ing the manuscript. This work was funded by grants from the National Basic Research and Development Program, China (2009CB 119004), Special Fund for Agro-scientific Research in the Public Interest (201103021) and the Nat- ural Science Foundation of China (31071709).
文摘Field trials were conducted in China in 2008 and 2009 to evaluate the efficacy of mating disruption (MD) on diamondback moth, Plutella xylostella, in cabbage, Brassica oleracea var. capitata. Effectiveness was positively correlated with the MD dispenser density in the field. A density of 167 MD dispensers per ha produced an average population decrease of about 50% compared to the conventional-practice field. Significant fewer males were captured in pheromone-treated and conventional-practice fields than in the blank control field, but the difference was not significant between the pheromone-treated and conventional-practice fields. In addition, fewer eggs and larvae were observed in pheromone-treated fields. Our results suggest mating disruption coupled with minimal insecticidal supplements is a promising solution for resistance management and control of diamondback moth infestation.
基金Special thanks to Dr.Xuguo Zhou(University of Kentucky)for his valuable suggestion on preparing this manuscript.This research was supported by the National Key R&D Program of China(2017YFD0200900)National Natural Science Foundation of China(31972269),and GDUPS(2017).The granting agencies had no role in the study design,data collection and analysis,decision to publish,or preparation of the manuscript.
文摘RNA interference(RNAi)techniques have emerged as powerful tools that facilitate development of novel management strategies for insect pests,such as Henosepilachna vigintioctopunctata(Coleoptera:Coccinellidae),which is a major pest of solanaceous plants in Asia.In this study,the potential of oral delivery of in vvYro-synthesized and bacterially expressed double-stranded H.vigintioctopunctata lesswright(Iwr)gene(dsHvlwr)to manage of H.vigintioctopunctata was investigated.Our results showed that the gene Hvlwr had a 480-bp open reading frame and encoded a 160-amino acid protein.Hvlwr expression levels were greater in the fat body than other tissue types.Hvlwr silencing led to greater H.vigintioctopunctata mortality rates and appeared to be time-and partially dose-dependent,likely as a result of the number of hemocytes increasing with dsRNA concentration,but decreasing with time.Bacterially expressed dsHvlwr that was applied to leaf discs caused 88%,66%,and 36%mortality in 1st instars,3rd instars,and adults after 10,10,and 14 d,respectively;when applied to living plants,there was greater mortality in 1 st and 3rd instars,but there was no effect on adults.Furthermore,dsHvlwr led to improved plant protection against H.vigintioctopunctata.Our study shows an effective dietary RNAi response in H.vigintioctopunctata and that Hvlwr is a promising RNAi target gene for control of this pest species.
基金supported by the National Key R&D Program of China(2019YFD1002100)China Agriculture Research System(CARS-24-C-02)+1 种基金the Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences(CAAS-ASTIP-IVFCAAS)he Beijing Key Laboratory for Pest Control and Sustainable Cultivation of Vegetables.
文摘The invasive pest whitefly(Bemisia tabaci)is a complex species,of which Middle East-Minor Asia 1(MEAM1)and Mediterranean(MED)are the two most damaging members.Previous research showed that cabbage is frequently infested with MEAM1 but seldomly with MED,and this difference in performance is associated with glucosi-nolate(GS)content.Some insects can modify GS using glucosinolate sulfatase(SULF),the activity of which is regulated by sulfatase modifying factor 1(SUMF1);therefore,to increase our understanding of different performances of MEAM1 and MED on cabbage plants,we identified and compared nine putative SULFs and one SUMF in MEAM1 and MED.We found that the lengths of two genes,BtSulf2 and BtSulf4,differed between MEAM1 and MED.The messenger RNA levels of BtSulf4 increased more than 20-fold after MEAMl and MED adults were exposed to GS,but BtSulJ2 expression was only induced by GS in MEAM1.Knockdown of BtSulf2 and BtSulf4 in MEAM1 resulted in a substantial increase in the mortality of GS-treated adults but not in MED.These results indicate that differences in BtSulJ2 and BtSulf4 sequences and/or expression may explain why MEAM1 performs better than MED on cabbage.Our results provide a basis for future functional research on SULF and SUMF in B.tabaci.
基金the National Key R&D Program of China(2017YFD0200400)National Natural Science Foundation of China(31371941,31572012,31772171,31601637)+1 种基金the Beijing Key Laboratory for Pest Control and Sustainable Cultivation of Vegetables,the Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences(CAAS-ASTIP-IVFCAAS)the Natural Science Fund of Tianjin(17JCZDJC33700).
文摘MEAMI(Middle East-Asia Minor 1."B"biotype)anpl MED(Mediterranean,"Q"biotype)are the two most destructive ery pie species of the Bemisia tabaci complex on the planet.Our previous studies have shown that MEAMI outcompets MED on cabbage;the underlying mechanism is unknown.In the Brassicaceae family,the glucosinolate-myrosinase defense system plays a crucial role im deterring feeding,inhibiting growth,and eausing acute toxicity against a wide range of generalist herbivores.In the present study.we first compared the surv ival of MEAMI and MED exposed to sinigin(a glucosinolate)and myosinase(an enzyme that degrades glucosinolates);we found that survival of both species was high in response 10 sinigrin alone bul was near zer0 in response to sinigrin+myrosinase.We then used electropenetrography(lectrical penetration graphs,EPG)to assess the feeding bchaviors of MEAMI and MED whiteflies on cabbage.The EPG results revealed that the me an dunution of each potential drop(pd,indicating an intreellular puncture)was subsantialy longer for MED than MEAMI on eabbage,indicating that the exposure to the toxic hydrolysates of glucosinolate and myrosinase is greater for MED than for MEAMI.We therefore conclude that dffreces in penetrating bchaviors may help explain the dfferent fiects of cabbuge on MEAMI and MED whitefly species.
文摘Diamondback moth, Plutella xylostella (L.) is one of the most serious insect pests for its remarkable ability to develop resistance to virtually every insecticide that has been used against it. In the present study, amplified fragment length poly- morphism (AFLP) is used to study the genetic differentiation as well as the effects of abamectin-selection on population genetic differentiation for P. xylostella. A dendrogram was constructed from the matrix of genetic distances using the STATISTICA software (Version 4.5) and unweighted pair-group method with arithmetic averages (UPGMA). The data demonstrated that compared to the susceptible strain (ABM-s), the heterozy- gosity in the abamectin-resistant strain (ABM-r) decreased with the increased selection pressure and resistant level. When the resistance ratio was below 4.3, there was no sig- nificant differentiation at the genome DNA level. When the resistance ratio reached 5.8, a fairly significant differentiation began to appear, and when the resistance ratio reached and exceeded 8.1, there appeared a significant genetic differentiation. The results suggest that abamectin selection is associated with increased genetic polymorphism in P. xylostella.