Begomoviruses and whiteflies have interacted for geological times.An assumed long-lasting virus-vector intimate relationship of this magnitude implies that the partners have developed co-evolutionary mechanisms that i...Begomoviruses and whiteflies have interacted for geological times.An assumed long-lasting virus-vector intimate relationship of this magnitude implies that the partners have developed co-evolutionary mechanisms that insure on one hand the survival and the efficient transmission of the virus,and on the other hand the safeguard of the insect host from possible deleterious effects of the virus.Several studies have indicated that viruses belonging to the Tomato yellow leaf curl virus（TYLCVs）family from China,Israel and Italy are reminiscent of insect pathogens.TYLCVs like all begomoviruses are transmitted in a circulative manner by the whitefly Bemisia tabaci.The survival of the virus in the haemolymph of B.tabaci is ensured by a GroEL homologue produced by a whitefly secondary endosymbiont.Following acquisition and transfer to non-host plants,the virus may remain associated with the insect for its entire 4-5 wk-long adult life.During this period,the ability of the insects to inoculate plants steadily decreased,but did not disappear.The long-term presence of TYLCVs in B.tabaci was associated with a decrease in the insect longevity and fertility.Viral DNA was transmitted to progeny,but seldom infectivity.TYLCV transcripts were found associated with the insects,raising the possibility of replication and expression in the vector.TYLCVs may spread amidst whiteflies during copulation.Functional genomics tools such as microarrays,deep sequencing,quantitative PCR and gene silencing allow revisiting the proposition that TYLCVs have retained,or acquired,some characteristics of an insect pathogen.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.展开更多
Okra is one of the most widespread vegetable crops in the world, particularly in West Africa. However, several factors influence okra crops as biotic and abiotic factors. Among the diseases affecting its culture, okra...Okra is one of the most widespread vegetable crops in the world, particularly in West Africa. However, several factors influence okra crops as biotic and abiotic factors. Among the diseases affecting its culture, okra leaf curl disease is a major threat. This study aims to assess begomoviruses from okra plants with symptoms like leaves curl by molecular approach. A total of thirteen serologically positive samples were tested by PCR assay, and one sample was sequenced among them. The begomovirus was found in six isolates, Bhendi yellow vein mosaic virus (BYVMV) in three isolates, and Okra enation leaf curl virus (OELCuV) in three isolates, respectively. The begomovirus isolate sequences shared 90% identity with the Cotton leaf curl Gezira virus. Mixed infections between these viruses were found. Thus, these results highlight the need to monitor the spread of these disease-causing viruses for okra crops in Mali. In addition, they can also lead to a considerable loss in okra fields in Koulikoro, which is an agricultural region by excellence.展开更多
Cassava mosaic disease (CMD) caused by Cassava Mosaic Begomoviruses (CMBs) is one of the most devastating crop diseases and a major constraint for cassava production. In order to ensure surveillance for epidemic preve...Cassava mosaic disease (CMD) caused by Cassava Mosaic Begomoviruses (CMBs) is one of the most devastating crop diseases and a major constraint for cassava production. In order to ensure surveillance for epidemic prevention, low-cost diagnostic tools are appropriate for large-scale testing of cassava viruses. Multiplex PCR diagnosis is one approach that can reduce diagnostic costs and delays. A multiplex PCR approach was developed for simultaneous detection of African cassava mosaic virus (ACMV), East African Cassava Mosaic Virus and East African cassava mosaic Cameroon virus (EACMV/CM) in Togo CMD-infected cassava leaves. Three primers pairs were used to target their respective viruses in a single tube PCR. Multiplex PCR detected ACMV, EACMV and EACMV/CM in plant DNA extracts prepared from cassava leaves infected with CMB. The primers amplified 783 bp specific to ACMV, 650 bp specific to EACMV and 560 bp specific to EACMCV/CM in both uniplex and multiplex formats. Multiplex PCR is an excellent tool for the effective control of cassava diseases. .展开更多
Cassava mosaic disease caused by the whitefly-transmitted begomoviruses (family Geminiviridae) is a major threat to cassava (Manihot esculenta Crantz) production, which can be intercropped with other plants such as pe...Cassava mosaic disease caused by the whitefly-transmitted begomoviruses (family Geminiviridae) is a major threat to cassava (Manihot esculenta Crantz) production, which can be intercropped with other plants such as pepper (Capsicum annuum L.). The aim of this study is to identify cassava begomoviruses on other crops in cassava intercropping systems. Thus, foliar samples showing typical symptoms of virus diseases in cassava intercropping systems were collected from pepper and submitted to PCR analysis and direct sequencing. Three begomovirus species ACMV, EACMV and ALCCMV were identified and characterized in samples. Isolates of these species shared respectively 90% - 93%, 74% and 80% nucleotide identities with begomoviruses. These findings show that cassava begomoviruses can infect other crops and will help in understanding the epidemiology related to whitefly-transmitted begomoviruses in cassava intercropping systems.展开更多
Geminiviruses, in particular the members of the genus Begomovirus , are considered to be a major phytosanitary problem for tomato crops production in the world. They are responsible for yield losses of up to 20% to 10...Geminiviruses, in particular the members of the genus Begomovirus , are considered to be a major phytosanitary problem for tomato crops production in the world. They are responsible for yield losses of up to 20% to 100%. Regrettably, Togo is not spared from this situation. This work aims to show the genetic diversity of the begomoviruses affecting tomato crops production in Togo and their relationship with other begomoviruses. To achieve these objectives, 307 samples of tomato leaves and wild plant species with typical virus symptoms were collected in the Maritime, Plateaus, Central, Kara and Savannah regions and submitted to PCR analysis. The results revealed the presence of begomovirus in 25.40% of the analyzed samples. The PCR products obtained were submitted to direct sequencing. Phylogenetic analysis of sequences of DNA-A different regions of begomovirus identified in this work with that of other begomoviruses showed a nucleotide identity of 96% respectively for Tomato leaf curl Togo virus-Fontem, Tomato Leaf Curl Togo Virus , Ageratum leaf curl Cameroon Alphasatellite;98% respectively to Tomato leaf curl Nigeria virus , Ageratum leaf curl Cameroon virus , Tomato leaf curl Cameroon virus-Fontem, Ageratum leaf curl Cameroon virus and 99% respectively to Tomato leaf curl Kumasi virus , Pepper yellow vein Mali virus Bazegahot and Pepper yellow vein Mali virus-Ouaga. These results suggest a high degree of genetic diversity of tomato begomoviruses identified in Togo.展开更多
A novel monopartite begomovirus was found in naturally infected Conyza canadensis plants exhibiting typical begomovirus-induced yellow vein symptoms in Yunnan Province of China.Analysis of two obtained full-length vir...A novel monopartite begomovirus was found in naturally infected Conyza canadensis plants exhibiting typical begomovirus-induced yellow vein symptoms in Yunnan Province of China.Analysis of two obtained full-length viral genome sequences showed that they shared 99.8%nucleotide(nt)sequence similarity,and both consisted of 2733 nts(GenBank accession no.OK120264 and OK120266,respectively).Further analysis showed that these two sequences shared the highest nt sequence similarity(78.9%)with tomato yellow leaf curl Vietnam virus(TYLCVV)(EU189150).In the assayed C.canadensis plants,a betasatellite of 1,341 nts(Accession no.OK120265 and OK120267,respectively)was also found,and it shared 98.1%sequence similarity with malvastrum yellow vein betasatellite(MaYVB)(JX679254).Based on the current classification criteria for begomoviruses,we consider that the two obtained viral isolates are a novel begomovirus,and named it as conyza yellow vein virus(CoYVV).Our further analysis result showed that CoYVV is likely originated from a recombination event between tomato yellow leaf curl Yunnan virus(TYLCYnV)and tomato yellow leaf curl China virus(TYLCCNV).To investigate the effect of CoYVV infection in plant,we constructed two infectious clones(i.e.,pCoYVV and pMaYVB),and inoculated them individually or together to Nicotiana benthamiana plants through agro-infiltration.The result showed that the plants co-inoculated with CoYVV and MaYVB developed yellow vein and downward leaf-curling symptoms,whereas the plants inoculated with CoYVV alone showed no clear virus-like symptoms.Virus infection in the inoculated N.benthamiana plants was confirmed through polymerase chain reaction(PCR).The result of quantitative PCR(qPCR)showed that in the presence of MaYVB,the accumulation level of CoYVV DNA was significantly increased compared to that in the plants infected with CoYVV alone.展开更多
Malvastrum coromandelianum is a common weed plant frequently found around agricultural fields.Three virus isolates(Y249,Y278 and Y281)were obtained from M.coromandelianum with yellow vein symptoms in Honghe and Baosha...Malvastrum coromandelianum is a common weed plant frequently found around agricultural fields.Three virus isolates(Y249,Y278 and Y281)were obtained from M.coromandelianum with yellow vein symptoms in Honghe and Baoshan,Yunnan Province,China.Specific 500 bp products were amplified from total DNA extracts using universal primers for members of the genus Begomovirus.The complete viral genome sequences of both Y278 and Y281 were determined to be 2743 nucleotides,and that of Y249 was determined to be 2740 nucleotides.Sequence alignments and phylogenetic analyses support the proposal of creating new species in the genus Begomovirus,for which the name malvastrum yellow vein Baoshan virus(MaYVBsV)is proposed for Y278 and Y281,and malvastrum yellow vein Honghe virus(MaYVHhV)is proposed for Y249.展开更多
Virus isolate Y1 was obtained from tobacco showing curly shoot symptoms in Baoshan, Yunnan Province. Whitefly transmission test and virion morphology observa-tion showed that it is a begomovirus. In reactions with 14 ...Virus isolate Y1 was obtained from tobacco showing curly shoot symptoms in Baoshan, Yunnan Province. Whitefly transmission test and virion morphology observa-tion showed that it is a begomovirus. In reactions with 14 monoclonal antibodies raised against begomoviruses, Y1 was readily differentiated from begomoviruses reported in China, Pakistan and India. The complete nucleotide sequence of DNA-A was determined, it contains 2746 nucleotides, with two ORFs in virion-sense DNA and four ORFs in comple-mentary-sense DNA. Comparisons with total DNA-A, inter-genie region and deduced amino acid sequences of individual ORFs showed that Y1 is a distinct Begomovirus species, for which the name Tobacco curly shoot virus (TCSV) is pro-posed. The total DNA-A of TCSV is most closely related to that of Tomato leaf curl virus from India (85% sequence identity). In contrast, the deduced coat protein of TCSV is most like that of Cotton leaf curl virus 72b isolate from Paki-stan (98% amino acid sequence identity).展开更多
Begomoviruses are important crop viral disease agents, and they are transmitted by whiteflies of the Bemisia tabaci complex.Although the transmission of begomoviruses by whiteflies has been studied for many years, the...Begomoviruses are important crop viral disease agents, and they are transmitted by whiteflies of the Bemisia tabaci complex.Although the transmission of begomoviruses by whiteflies has been studied for many years, the mechanisms governing differential transmission of begomoviruses by different species of the Bemisia tabaci complex remain largely unknown. Here we firstly compared the transmission efficiency of tobacco curly shoot virus(TbCSV) by four species of the B. tabaci complex and found that Asia II 1 transmitted this virus with the highest efficiency, whereas MEAM1 transmitted it with the lowest. Next, by performing quantitative analysis of virus and immune-fluorescence detection, we found that the efficiency of TbCSV to cross the midgut wall was higher in Asia II 1 than in MEAM1. Finally, we set the quantities of virions in the haemolymph to the same level in Asia II 1 and MEAM1 via injection and then compared their capacity in TbCSV transmission, and found that the difference in TbCSV transmission between them became smaller. Taken together, our findings suggest that the efficiency of a begomovirus to cross the midgut wall of a whitefly to reach the vector's haemolymph plays a significant role in determining transmission of the virus.展开更多
The bipartite begomoviruses (Geminiviridae family), which are DNA viruses that replicate in the nucleus of infected cells, encode the nuclear shuttle protein (NSP) to facilitate the translocation of viral DNA from the...The bipartite begomoviruses (Geminiviridae family), which are DNA viruses that replicate in the nucleus of infected cells, encode the nuclear shuttle protein (NSP) to facilitate the translocation of viral DNA from the nucleus to the cytoplasm via nuclear pores. This intracellular trafficking of NSP-DNA complexes is accessorized by the NSP-interacting guanosine triphosphatase (NIG) at the cytosolic side. Here, we report the nuclear redistribution of NIG by AtWWPI, a WW domain-containing protein that forms immune nuclear bodies (NBs) against begomoviruses. We demonstrated that AtWWPI relocates NIG from the cytoplasm to the nucleus where it is confined to AtWWP1-NBs, suggesting that the NIG-AtWWP1 interaction may interfere with the NIG pro-viral function associated with its cytosolic localization. Consistent with this assumpti on joss AtWWPI functi on cuased plants more susceptible to begomovirus infection, whereas overexpression of AWWP1 enhaneed plant resistance to begomovirus. Furthermore, we found that a mutant versi on of AtWWPI defective for NB formatio n was noIonger capable of interacti ng with and relocating NIG to the nucleus and lost its immune function against begomovirus. The antiviral function of AtWWP1-NBs, however, could be antagonized by viral infection that induced either the disruption or a decrease in the number of AtWWP1-NBs. Collectively, these results led us to propose that AtWWPI organizes nuclear structures into nuclear foci, which provide intrinsic immunity against begomovirus infection.展开更多
基金Supported by grant IS-4062-07 from the United States-Israel Binational Agricultural Research and Development Fund(BARD)to Czosnek H and Ghanim Mresearchgrant 887/07from the Israel Science Foundation(ISF)to C.H.and G.M.research grant 42-204.2/2006from theGerman-Israel Foundation(GIF) to C.H.and G.M
文摘Begomoviruses and whiteflies have interacted for geological times.An assumed long-lasting virus-vector intimate relationship of this magnitude implies that the partners have developed co-evolutionary mechanisms that insure on one hand the survival and the efficient transmission of the virus,and on the other hand the safeguard of the insect host from possible deleterious effects of the virus.Several studies have indicated that viruses belonging to the Tomato yellow leaf curl virus（TYLCVs）family from China,Israel and Italy are reminiscent of insect pathogens.TYLCVs like all begomoviruses are transmitted in a circulative manner by the whitefly Bemisia tabaci.The survival of the virus in the haemolymph of B.tabaci is ensured by a GroEL homologue produced by a whitefly secondary endosymbiont.Following acquisition and transfer to non-host plants,the virus may remain associated with the insect for its entire 4-5 wk-long adult life.During this period,the ability of the insects to inoculate plants steadily decreased,but did not disappear.The long-term presence of TYLCVs in B.tabaci was associated with a decrease in the insect longevity and fertility.Viral DNA was transmitted to progeny,but seldom infectivity.TYLCV transcripts were found associated with the insects,raising the possibility of replication and expression in the vector.TYLCVs may spread amidst whiteflies during copulation.Functional genomics tools such as microarrays,deep sequencing,quantitative PCR and gene silencing allow revisiting the proposition that TYLCVs have retained,or acquired,some characteristics of an insect pathogen.
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.
文摘Okra is one of the most widespread vegetable crops in the world, particularly in West Africa. However, several factors influence okra crops as biotic and abiotic factors. Among the diseases affecting its culture, okra leaf curl disease is a major threat. This study aims to assess begomoviruses from okra plants with symptoms like leaves curl by molecular approach. A total of thirteen serologically positive samples were tested by PCR assay, and one sample was sequenced among them. The begomovirus was found in six isolates, Bhendi yellow vein mosaic virus (BYVMV) in three isolates, and Okra enation leaf curl virus (OELCuV) in three isolates, respectively. The begomovirus isolate sequences shared 90% identity with the Cotton leaf curl Gezira virus. Mixed infections between these viruses were found. Thus, these results highlight the need to monitor the spread of these disease-causing viruses for okra crops in Mali. In addition, they can also lead to a considerable loss in okra fields in Koulikoro, which is an agricultural region by excellence.
文摘Cassava mosaic disease (CMD) caused by Cassava Mosaic Begomoviruses (CMBs) is one of the most devastating crop diseases and a major constraint for cassava production. In order to ensure surveillance for epidemic prevention, low-cost diagnostic tools are appropriate for large-scale testing of cassava viruses. Multiplex PCR diagnosis is one approach that can reduce diagnostic costs and delays. A multiplex PCR approach was developed for simultaneous detection of African cassava mosaic virus (ACMV), East African Cassava Mosaic Virus and East African cassava mosaic Cameroon virus (EACMV/CM) in Togo CMD-infected cassava leaves. Three primers pairs were used to target their respective viruses in a single tube PCR. Multiplex PCR detected ACMV, EACMV and EACMV/CM in plant DNA extracts prepared from cassava leaves infected with CMB. The primers amplified 783 bp specific to ACMV, 650 bp specific to EACMV and 560 bp specific to EACMCV/CM in both uniplex and multiplex formats. Multiplex PCR is an excellent tool for the effective control of cassava diseases. .
基金This work was supported by International Foundation of Science(IFS)research grant C/5596-1 to K.A.Dansou-Kodjoand by West African Virus Epidemiology for Togo(WAVE-UL)project.
文摘Cassava mosaic disease caused by the whitefly-transmitted begomoviruses (family Geminiviridae) is a major threat to cassava (Manihot esculenta Crantz) production, which can be intercropped with other plants such as pepper (Capsicum annuum L.). The aim of this study is to identify cassava begomoviruses on other crops in cassava intercropping systems. Thus, foliar samples showing typical symptoms of virus diseases in cassava intercropping systems were collected from pepper and submitted to PCR analysis and direct sequencing. Three begomovirus species ACMV, EACMV and ALCCMV were identified and characterized in samples. Isolates of these species shared respectively 90% - 93%, 74% and 80% nucleotide identities with begomoviruses. These findings show that cassava begomoviruses can infect other crops and will help in understanding the epidemiology related to whitefly-transmitted begomoviruses in cassava intercropping systems.
基金the West African Agricultural Productivity Program(WAAPP/TOGO)and Bill and Melinda Gates Foundation(BMGF)for supporting this project.
文摘Geminiviruses, in particular the members of the genus Begomovirus , are considered to be a major phytosanitary problem for tomato crops production in the world. They are responsible for yield losses of up to 20% to 100%. Regrettably, Togo is not spared from this situation. This work aims to show the genetic diversity of the begomoviruses affecting tomato crops production in Togo and their relationship with other begomoviruses. To achieve these objectives, 307 samples of tomato leaves and wild plant species with typical virus symptoms were collected in the Maritime, Plateaus, Central, Kara and Savannah regions and submitted to PCR analysis. The results revealed the presence of begomovirus in 25.40% of the analyzed samples. The PCR products obtained were submitted to direct sequencing. Phylogenetic analysis of sequences of DNA-A different regions of begomovirus identified in this work with that of other begomoviruses showed a nucleotide identity of 96% respectively for Tomato leaf curl Togo virus-Fontem, Tomato Leaf Curl Togo Virus , Ageratum leaf curl Cameroon Alphasatellite;98% respectively to Tomato leaf curl Nigeria virus , Ageratum leaf curl Cameroon virus , Tomato leaf curl Cameroon virus-Fontem, Ageratum leaf curl Cameroon virus and 99% respectively to Tomato leaf curl Kumasi virus , Pepper yellow vein Mali virus Bazegahot and Pepper yellow vein Mali virus-Ouaga. These results suggest a high degree of genetic diversity of tomato begomoviruses identified in Togo.
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.XDJK2017A006).
文摘A novel monopartite begomovirus was found in naturally infected Conyza canadensis plants exhibiting typical begomovirus-induced yellow vein symptoms in Yunnan Province of China.Analysis of two obtained full-length viral genome sequences showed that they shared 99.8%nucleotide(nt)sequence similarity,and both consisted of 2733 nts(GenBank accession no.OK120264 and OK120266,respectively).Further analysis showed that these two sequences shared the highest nt sequence similarity(78.9%)with tomato yellow leaf curl Vietnam virus(TYLCVV)(EU189150).In the assayed C.canadensis plants,a betasatellite of 1,341 nts(Accession no.OK120265 and OK120267,respectively)was also found,and it shared 98.1%sequence similarity with malvastrum yellow vein betasatellite(MaYVB)(JX679254).Based on the current classification criteria for begomoviruses,we consider that the two obtained viral isolates are a novel begomovirus,and named it as conyza yellow vein virus(CoYVV).Our further analysis result showed that CoYVV is likely originated from a recombination event between tomato yellow leaf curl Yunnan virus(TYLCYnV)and tomato yellow leaf curl China virus(TYLCCNV).To investigate the effect of CoYVV infection in plant,we constructed two infectious clones(i.e.,pCoYVV and pMaYVB),and inoculated them individually or together to Nicotiana benthamiana plants through agro-infiltration.The result showed that the plants co-inoculated with CoYVV and MaYVB developed yellow vein and downward leaf-curling symptoms,whereas the plants inoculated with CoYVV alone showed no clear virus-like symptoms.Virus infection in the inoculated N.benthamiana plants was confirmed through polymerase chain reaction(PCR).The result of quantitative PCR(qPCR)showed that in the presence of MaYVB,the accumulation level of CoYVV DNA was significantly increased compared to that in the plants infected with CoYVV alone.
基金supported by a grant from the National Natural Science Foundation of China to Yaqin Wang(31972235).
文摘Malvastrum coromandelianum is a common weed plant frequently found around agricultural fields.Three virus isolates(Y249,Y278 and Y281)were obtained from M.coromandelianum with yellow vein symptoms in Honghe and Baoshan,Yunnan Province,China.Specific 500 bp products were amplified from total DNA extracts using universal primers for members of the genus Begomovirus.The complete viral genome sequences of both Y278 and Y281 were determined to be 2743 nucleotides,and that of Y249 was determined to be 2740 nucleotides.Sequence alignments and phylogenetic analyses support the proposal of creating new species in the genus Begomovirus,for which the name malvastrum yellow vein Baoshan virus(MaYVBsV)is proposed for Y278 and Y281,and malvastrum yellow vein Honghe virus(MaYVHhV)is proposed for Y249.
基金This work was partially supported by the National Science Fund for Distinguished Young Scholars (Grant No. 30125032) the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of MOE The work was also sup
文摘Virus isolate Y1 was obtained from tobacco showing curly shoot symptoms in Baoshan, Yunnan Province. Whitefly transmission test and virion morphology observa-tion showed that it is a begomovirus. In reactions with 14 monoclonal antibodies raised against begomoviruses, Y1 was readily differentiated from begomoviruses reported in China, Pakistan and India. The complete nucleotide sequence of DNA-A was determined, it contains 2746 nucleotides, with two ORFs in virion-sense DNA and four ORFs in comple-mentary-sense DNA. Comparisons with total DNA-A, inter-genie region and deduced amino acid sequences of individual ORFs showed that Y1 is a distinct Begomovirus species, for which the name Tobacco curly shoot virus (TCSV) is pro-posed. The total DNA-A of TCSV is most closely related to that of Tomato leaf curl virus from India (85% sequence identity). In contrast, the deduced coat protein of TCSV is most like that of Cotton leaf curl virus 72b isolate from Paki-stan (98% amino acid sequence identity).
基金supported by the National Natural Science Foundation of China (31390421)
文摘Begomoviruses are important crop viral disease agents, and they are transmitted by whiteflies of the Bemisia tabaci complex.Although the transmission of begomoviruses by whiteflies has been studied for many years, the mechanisms governing differential transmission of begomoviruses by different species of the Bemisia tabaci complex remain largely unknown. Here we firstly compared the transmission efficiency of tobacco curly shoot virus(TbCSV) by four species of the B. tabaci complex and found that Asia II 1 transmitted this virus with the highest efficiency, whereas MEAM1 transmitted it with the lowest. Next, by performing quantitative analysis of virus and immune-fluorescence detection, we found that the efficiency of TbCSV to cross the midgut wall was higher in Asia II 1 than in MEAM1. Finally, we set the quantities of virions in the haemolymph to the same level in Asia II 1 and MEAM1 via injection and then compared their capacity in TbCSV transmission, and found that the difference in TbCSV transmission between them became smaller. Taken together, our findings suggest that the efficiency of a begomovirus to cross the midgut wall of a whitefly to reach the vector's haemolymph plays a significant role in determining transmission of the virus.
文摘The bipartite begomoviruses (Geminiviridae family), which are DNA viruses that replicate in the nucleus of infected cells, encode the nuclear shuttle protein (NSP) to facilitate the translocation of viral DNA from the nucleus to the cytoplasm via nuclear pores. This intracellular trafficking of NSP-DNA complexes is accessorized by the NSP-interacting guanosine triphosphatase (NIG) at the cytosolic side. Here, we report the nuclear redistribution of NIG by AtWWPI, a WW domain-containing protein that forms immune nuclear bodies (NBs) against begomoviruses. We demonstrated that AtWWPI relocates NIG from the cytoplasm to the nucleus where it is confined to AtWWP1-NBs, suggesting that the NIG-AtWWP1 interaction may interfere with the NIG pro-viral function associated with its cytosolic localization. Consistent with this assumpti on joss AtWWPI functi on cuased plants more susceptible to begomovirus infection, whereas overexpression of AWWP1 enhaneed plant resistance to begomovirus. Furthermore, we found that a mutant versi on of AtWWPI defective for NB formatio n was noIonger capable of interacti ng with and relocating NIG to the nucleus and lost its immune function against begomovirus. The antiviral function of AtWWP1-NBs, however, could be antagonized by viral infection that induced either the disruption or a decrease in the number of AtWWP1-NBs. Collectively, these results led us to propose that AtWWPI organizes nuclear structures into nuclear foci, which provide intrinsic immunity against begomovirus infection.
