Papaya leaf curl China virus (PaLCuCNV) was previously reported as a distinct begomovirus infecting papaya in southern China. Based on molecular diagnostic survey, 13 PaLCuCNV isolates were obtained from tomato plants...Papaya leaf curl China virus (PaLCuCNV) was previously reported as a distinct begomovirus infecting papaya in southern China. Based on molecular diagnostic survey, 13 PaLCuCNV isolates were obtained from tomato plants showing leaf curl symptoms in Henan and Guangxi Provinces of China. Complete nucleotide sequences of 5 representative isolates (AJ558116, AJ558117, AJ704604, FN256260, and FN297834) were determined to be 2738–2751 nucleotides, which share 91.7%–97.9% sequence identities with PaLCuCNV isolate G2 (AJ558123). DNA-β was not found to be associated with PaLCuCNV isolates. To investigate the infectivity of PaLCuCNV, an in-fectious clone of PaLCuCNV-[CN:HeNZM1] was constructed and agro-inoculated into Nicotiana benthamiana, N. tabacum Samsun, N. glutinosa, Solanum lycopersicum and Petunia hybrida plants, which induced severe leaf curling and crinkling symptoms in these plants. Southern blot analysis and polymerase chain reaction (PCR) indicated a systemic infection of test plants by the agro-infectious clone.展开更多
Chinese tomato yellow leaf curl virus (TYLCV CHI) and other geminiviruses were analysed with 20 monoclonal antibodies. It was shown that TYLCV CHI is serologically close to Chinese tabacco leaf curl virus (TbLCV CHI)....Chinese tomato yellow leaf curl virus (TYLCV CHI) and other geminiviruses were analysed with 20 monoclonal antibodies. It was shown that TYLCV CHI is serologically close to Chinese tabacco leaf curl virus (TbLCV CHI). The fragment of TYLCV CHI DNA including the common region (CR), N terminal of coat protein gene and AV1 gene was amplified by PCR and cloned, and its DNA sequence was determined. These results showed that TYLCV CHI is different from other known geminiviruses in the world, and is a new whitefly transmitted geminivirus.展开更多
A circular DNA molecule, designated as DNAp, was identified in tobacco plants infected with Tobacco leaf curl virus (TLCV) isolates Y5 and Y8 by PCR using primers based on the conserved region of the two reported DNAp...A circular DNA molecule, designated as DNAp, was identified in tobacco plants infected with Tobacco leaf curl virus (TLCV) isolates Y5 and Y8 by PCR using primers based on the conserved region of the two reported DNAp sequences of whitefly-transmitted geminiviruses (WTGs). The complete nucleotide sequences of DNAβ of Y5 and Y8 (TLCV DNAβ) were determined. Y5 DNAβ comprises 1333 nucleotides encoding 8 predicted ORFs with 4 ORFs in virion-sense DNA and 4 ORFs in complementary-sense DNA; Y8 DNAP consists of 1338 nucleotides encoding 7 predicted ORFs with 4 ORFs in virion-sense DNA and 3 ORFs in complementary-sense DNA. TLCV DNAβhas little sequence homology to DNA-A of TLCV, except that it shares conserved TAATATTAC loop sequence with TLCV DNA-A. Sequence comparison showed that Y5 DNAβ shared 85% sequence homology with Y8 DNAβ, and both Y5 DNAβ and Y8 DNAβ had relatively low sequence identity (51%-65%) with the reported DNAβ molecules associated with Agera-tum yellow vein virus and Cotton leaf展开更多
Coat protein (CP) gene of the Chinese squash !eaf curl virus (SqLCV-C) was amplified through PC’R, cloned and completely sequenced. Based on the comparisons at the levels of both CP gene nucleotide and CP -deduced am...Coat protein (CP) gene of the Chinese squash !eaf curl virus (SqLCV-C) was amplified through PC’R, cloned and completely sequenced. Based on the comparisons at the levels of both CP gene nucleotide and CP -deduced amino acid sequences with other geminiviruses, SqLCV-C is confirmed to be distinct from the American squash leaf curl virus (SqLCV-E). It is a new geminivirus transmitted by whitefly Bemisia tabaci, which infects dicotyledonous plants and is more closely related to the Indian cassava mosaic virus (ICMV).展开更多
It has been reported that squash leaf curl China virus(SLCCNV)infects some Cucurbitaceae crops except for melon(Cucumis melo L.).A new disease of melon exhibiting severe leaf curl and dwarfing was observed in Hainan P...It has been reported that squash leaf curl China virus(SLCCNV)infects some Cucurbitaceae crops except for melon(Cucumis melo L.).A new disease of melon exhibiting severe leaf curl and dwarfing was observed in Hainan Province of China.In this study,the pathogen was identified as SLCCNV through biological and molecular characterization.The isolate(SLCCNV-HN)possess a bipartite genome,DNA-A(HM566112.1)with the highest nucleotide identity(99%)to SLCCNV-Hn(MF062251.1)pumpkin and SLCCNV-Hn61(AM260205.1)squash isolates from China,whereas DNA-B(HM566113.1)with the highest nucleotide identity(99%)to SLCCNV-Hn(MF062252.1).Phylogenetic analyses based on the full-length SLCCNV-HN DNA-A and-B sequences indicated that SLCCNV-HN melon isolate is clustered with SLCCNV-Hn pumpkin,SLCCNV-Hn61 and SLCCNV-SY squash isolates from southern China,forming an independent cluster.Infectious clone of SLCCNV-HN was constructed and the melon plants were inoculated and the infection rate is 100%,the systemic symptoms in melon showed identical to those of melon plants infected in fields.Additionally,melon plants transmission of this virus by Bemisia tabaci with a transmission rate of 95%(19/20)showed leaf curl and dwarf symptoms 15 days post transmission,thereby fulfilling Koch’s postulates.Analysis of genomic organization and phylogenetic trees indicated that SLCCNV-HN melon isolate belongs to the Begomovirus genus.To the best of our knowledge,this is the first characterization of meloninfecting SLCCNV through its genome,infectious clone and transmission.展开更多
Analysis of climatological observation temperature data reveals that during the southwesterly monsoon, there exists a low tempera- ture zone east of Vietnam. It cools down from June to August and warms up in September...Analysis of climatological observation temperature data reveals that during the southwesterly monsoon, there exists a low tempera- ture zone east of Vietnam. It cools down from June to August and warms up in September. Meanwhile, during this period, the cold water mass spreads eastward to the deep basin. Numerical experiments validate the results of data analysis and further verify that there are two basic factors that induce the Vietnam cold water. The major one is the strong local positive wind stress curl, which leads to the divergence of sea surface water and the upward supplement of lower layer water in the deep basin. Another minor one is the alongshore component of southwesterly monsoon, which drives the offshore Ekman transport and coastal upwelling in the shallow region along the Vietnam coast. In addition, the negative wind stress curl in the southern South China Sea inputs negative vorticity to the ocean and drives a strong anticyclonic gyre, which affects the spatial distribution of the cold water evidently.展开更多
Tomato yellow leaf curl virus（TYLCV）is a species of the family Geminiviridae,causing serious yield losses in tomato production.The coat protein（CP）gene of TYLCV isolate SH2 was expressed in Escherichia coli BL21（...Tomato yellow leaf curl virus（TYLCV）is a species of the family Geminiviridae,causing serious yield losses in tomato production.The coat protein（CP）gene of TYLCV isolate SH2 was expressed in Escherichia coli BL21（DE3）using pET-32a as the expression vector.The recombinant protein was purified through Ni＋-NTA affinity column and used to immunize BALB/c mice.Three hybridoma cell lines（2B2,2E3 and 3E10）secreting monoclonal antibodies（MAbs）against TYLCV CP were obtained by fusing mouse myeloma cells（Sp 2/0）with spleen cells from the immunized BALB/c mouse.The titers of ascitic fluids of three MAbs ranged from 10-6 to 10-7 in indirect-ELISA.Isotypes and subclasses of all the MAbs belonged to IgG1,κ light chain.Triple antibody sandwich enzyme-linked immunosorbent assay（TAS-ELISA）showed that the MAb 3E10 could react with five begomoviruses infecting tomato,while the other two（2B2 and 2E3）mainly reacted with TYLCV.TAS-ELISA was set up using the MAb 3E10,and the established method could successfully detect virus in plant sap at 1：2 560（w/v,g mL-1）.Detection of field samples showed that begomoviruses were common in tomato crops in Zhejiang Province,China.展开更多
Using Morlet wavelet transform we investi-gated the intraseasonal variability of the subsurface tem-perature in the SCS by analyzing ATLAS mooring data ob-tained during the South China Sea Monsoon Experiment (SCSMEX)....Using Morlet wavelet transform we investi-gated the intraseasonal variability of the subsurface tem-perature in the SCS by analyzing ATLAS mooring data ob-tained during the South China Sea Monsoon Experiment (SCSMEX). It is found for the first time that subsurface temperature in the SCS exists intraseasonal variability, par-ticularly in winter. The strongest intraseasonal variability ranges from 50 to 100 m with its maximum amplitude about 1.0-2.0℃. The subsurface temperature intraseasonal vari-ability in the SCS is primarily induced by local wind stress curl via adjusting the vertical displacement of thermocline. It reveals the important characteristic of intraseasonal varia-tions in the SCS upper ocean vertically.展开更多
Begomoviruses are exclusively transmitted by whitefly （Bemisia tabaci） in a circulative, non-propagative manner. The influences of begomoviruses on whitefly vector are complex with both direct and indirect effects. ...Begomoviruses are exclusively transmitted by whitefly （Bemisia tabaci） in a circulative, non-propagative manner. The influences of begomoviruses on whitefly vector are complex with both direct and indirect effects. However, the molecular mechanisms underlying these effects are poorly understood and the transcriptional profiles of whitefly on healthy and virus-infected plants have not yet been studied. Using suppression subtractive hybridization, we investigated the differentially expressed genes in whitefly Middle East - Asia Minor 1 feeding on healthy and Tomato yellow leaf curl China virus （TYLCCNV） infected tobacco. From the forward cDNA library, 124 differentially expressed expression sequence tags （ESTs） were obtained which represent up-regulated genes in the whiteflies feeding on the infected tobacco. From the reverse library, 112 ESTs were isolated which represent down-regulated genes. Among the up-regulated genes, we identified several genes that are probably involved in direct interaction between whitefly and TYLCCN~, including a 26/29-kDa proteinase that appears to participate in the elimination of foreign proteins, heparan sulfate proteoglycan which mediates the entry of several viruses into host cells and two genes of Rickettsia-a secondary endosymbiotic bacterium of whitefly. In addition, we identified a number of genes involved in metabolism, transcription and translation which might be the result of indirect effects of TYLCCNV on the whitefly via host plants. Collectively, our results suggest that TYLCCNV-infected tobacco changes the gene expression profiles of whitefly via both direct and indirect interactions. This study revealed a number of genes involved in whitefly-TYLCCNV-tobacco interactions and provided useful information for future study on this complex system.展开更多
Virus-induced gene silencing （VIGS） is a useful technique for rapid plant gene function analysis. We recently reported a new VIGS vector modified from Tomato yellow leaf curl China virus （TYLCCNV） DNAβ （DNAm β...Virus-induced gene silencing （VIGS） is a useful technique for rapid plant gene function analysis. We recently reported a new VIGS vector modified from Tomato yellow leaf curl China virus （TYLCCNV） DNAβ （DNAm β）. In this study we compared in detail DNAmβ-induced gene silencing in four Nicotiana species including N. benthamiana, N. glutinosa, N. tabacum and N. paniculata. We found that DNAmβ-induced gene silencing in the four species was distinct in developing dynamics, tissue specificity, efficiency, and constancy in the plant life span. It was most efficient in N. benthamiana, where development of VIGS was most rapid, without tissue specificity and nearly 100% efficient. DNAmβ-induced gene silencing in N. glutinosa was also efficient despite being slightly less than in N. benthamiana. It initially occurred in veins, later was scattered to mesophyll, finally led to complete silencing in whole leaves. In both species, VIGS constantly expressed until the plants died. However, DNAmβ-mediated VIGS in the other two Nicotiana species, N. tabacum and N. paniculata, was significantly less efficient. It was strictly limited within the veins of the silenced leaves, and constantly occurred only over 3-4 weeks. The upper leaves that emerged later stopped showing the silencing phenotype. DNAmβ-induced gene silencing in N. benthamiana and N. glutinosa was not significantly influenced by the growth stage when the plants were agro-inoculated, and was not sensitive to high growth temperature up to 32℃. Our results indicate that this system has great potential as a versatile VIGS system for routine functional analysis of genes in some Nicotiana species.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 30530520)the Zhejiang Agricultural Science and Tech-nology Key Research Projects (No. 2007C12054)the Natural Science Foundation of Zhejiang Province, China (No. Y307397)
文摘Papaya leaf curl China virus (PaLCuCNV) was previously reported as a distinct begomovirus infecting papaya in southern China. Based on molecular diagnostic survey, 13 PaLCuCNV isolates were obtained from tomato plants showing leaf curl symptoms in Henan and Guangxi Provinces of China. Complete nucleotide sequences of 5 representative isolates (AJ558116, AJ558117, AJ704604, FN256260, and FN297834) were determined to be 2738–2751 nucleotides, which share 91.7%–97.9% sequence identities with PaLCuCNV isolate G2 (AJ558123). DNA-β was not found to be associated with PaLCuCNV isolates. To investigate the infectivity of PaLCuCNV, an in-fectious clone of PaLCuCNV-[CN:HeNZM1] was constructed and agro-inoculated into Nicotiana benthamiana, N. tabacum Samsun, N. glutinosa, Solanum lycopersicum and Petunia hybrida plants, which induced severe leaf curling and crinkling symptoms in these plants. Southern blot analysis and polymerase chain reaction (PCR) indicated a systemic infection of test plants by the agro-infectious clone.
文摘Chinese tomato yellow leaf curl virus (TYLCV CHI) and other geminiviruses were analysed with 20 monoclonal antibodies. It was shown that TYLCV CHI is serologically close to Chinese tabacco leaf curl virus (TbLCV CHI). The fragment of TYLCV CHI DNA including the common region (CR), N terminal of coat protein gene and AV1 gene was amplified by PCR and cloned, and its DNA sequence was determined. These results showed that TYLCV CHI is different from other known geminiviruses in the world, and is a new whitefly transmitted geminivirus.
基金This work was partially supported by the National Outstanding Youth Foundation (Grant No.30125032) the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of MOE also by the National Natural Science F
文摘A circular DNA molecule, designated as DNAp, was identified in tobacco plants infected with Tobacco leaf curl virus (TLCV) isolates Y5 and Y8 by PCR using primers based on the conserved region of the two reported DNAp sequences of whitefly-transmitted geminiviruses (WTGs). The complete nucleotide sequences of DNAβ of Y5 and Y8 (TLCV DNAβ) were determined. Y5 DNAβ comprises 1333 nucleotides encoding 8 predicted ORFs with 4 ORFs in virion-sense DNA and 4 ORFs in complementary-sense DNA; Y8 DNAP consists of 1338 nucleotides encoding 7 predicted ORFs with 4 ORFs in virion-sense DNA and 3 ORFs in complementary-sense DNA. TLCV DNAβhas little sequence homology to DNA-A of TLCV, except that it shares conserved TAATATTAC loop sequence with TLCV DNA-A. Sequence comparison showed that Y5 DNAβ shared 85% sequence homology with Y8 DNAβ, and both Y5 DNAβ and Y8 DNAβ had relatively low sequence identity (51%-65%) with the reported DNAβ molecules associated with Agera-tum yellow vein virus and Cotton leaf
文摘Coat protein (CP) gene of the Chinese squash !eaf curl virus (SqLCV-C) was amplified through PC’R, cloned and completely sequenced. Based on the comparisons at the levels of both CP gene nucleotide and CP -deduced amino acid sequences with other geminiviruses, SqLCV-C is confirmed to be distinct from the American squash leaf curl virus (SqLCV-E). It is a new geminivirus transmitted by whitefly Bemisia tabaci, which infects dicotyledonous plants and is more closely related to the Indian cassava mosaic virus (ICMV).
基金supported by the National Natural Science Foundation of China (31701941 and 31401810)the grants from the earmarked fund for China Agriculture Research System (CARS-26-13)the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences (ASTIP) (CAAS-ASTIP-2018-ZFRI-08)
文摘It has been reported that squash leaf curl China virus(SLCCNV)infects some Cucurbitaceae crops except for melon(Cucumis melo L.).A new disease of melon exhibiting severe leaf curl and dwarfing was observed in Hainan Province of China.In this study,the pathogen was identified as SLCCNV through biological and molecular characterization.The isolate(SLCCNV-HN)possess a bipartite genome,DNA-A(HM566112.1)with the highest nucleotide identity(99%)to SLCCNV-Hn(MF062251.1)pumpkin and SLCCNV-Hn61(AM260205.1)squash isolates from China,whereas DNA-B(HM566113.1)with the highest nucleotide identity(99%)to SLCCNV-Hn(MF062252.1).Phylogenetic analyses based on the full-length SLCCNV-HN DNA-A and-B sequences indicated that SLCCNV-HN melon isolate is clustered with SLCCNV-Hn pumpkin,SLCCNV-Hn61 and SLCCNV-SY squash isolates from southern China,forming an independent cluster.Infectious clone of SLCCNV-HN was constructed and the melon plants were inoculated and the infection rate is 100%,the systemic symptoms in melon showed identical to those of melon plants infected in fields.Additionally,melon plants transmission of this virus by Bemisia tabaci with a transmission rate of 95%(19/20)showed leaf curl and dwarf symptoms 15 days post transmission,thereby fulfilling Koch’s postulates.Analysis of genomic organization and phylogenetic trees indicated that SLCCNV-HN melon isolate belongs to the Begomovirus genus.To the best of our knowledge,this is the first characterization of meloninfecting SLCCNV through its genome,infectious clone and transmission.
基金supported by the Chinese Academy of Sciences under contract No.kzcx3-sw-227the National Natural Science Foundation of China under contract No.40406006.
文摘Analysis of climatological observation temperature data reveals that during the southwesterly monsoon, there exists a low tempera- ture zone east of Vietnam. It cools down from June to August and warms up in September. Meanwhile, during this period, the cold water mass spreads eastward to the deep basin. Numerical experiments validate the results of data analysis and further verify that there are two basic factors that induce the Vietnam cold water. The major one is the strong local positive wind stress curl, which leads to the divergence of sea surface water and the upward supplement of lower layer water in the deep basin. Another minor one is the alongshore component of southwesterly monsoon, which drives the offshore Ekman transport and coastal upwelling in the shallow region along the Vietnam coast. In addition, the negative wind stress curl in the southern South China Sea inputs negative vorticity to the ocean and drives a strong anticyclonic gyre, which affects the spatial distribution of the cold water evidently.
基金supported by the Special Fund for Agro-Scientific Research in the Public Interest from the Ministry of Agriculture,China(201003065)
文摘Tomato yellow leaf curl virus（TYLCV）is a species of the family Geminiviridae,causing serious yield losses in tomato production.The coat protein（CP）gene of TYLCV isolate SH2 was expressed in Escherichia coli BL21（DE3）using pET-32a as the expression vector.The recombinant protein was purified through Ni＋-NTA affinity column and used to immunize BALB/c mice.Three hybridoma cell lines（2B2,2E3 and 3E10）secreting monoclonal antibodies（MAbs）against TYLCV CP were obtained by fusing mouse myeloma cells（Sp 2/0）with spleen cells from the immunized BALB/c mouse.The titers of ascitic fluids of three MAbs ranged from 10-6 to 10-7 in indirect-ELISA.Isotypes and subclasses of all the MAbs belonged to IgG1,κ light chain.Triple antibody sandwich enzyme-linked immunosorbent assay（TAS-ELISA）showed that the MAb 3E10 could react with five begomoviruses infecting tomato,while the other two（2B2 and 2E3）mainly reacted with TYLCV.TAS-ELISA was set up using the MAb 3E10,and the established method could successfully detect virus in plant sap at 1：2 560（w/v,g mL-1）.Detection of field samples showed that begomoviruses were common in tomato crops in Zhejiang Province,China.
基金This work was supported by RFDP (Grant No. 1999042308) by SCSIO Open Laboratory for Tropical Marine Environmental Dynamics. Institute of Oceanology, Taiwan University provided the three ATLAS mooring buoy observation data.
文摘Using Morlet wavelet transform we investi-gated the intraseasonal variability of the subsurface tem-perature in the SCS by analyzing ATLAS mooring data ob-tained during the South China Sea Monsoon Experiment (SCSMEX). It is found for the first time that subsurface temperature in the SCS exists intraseasonal variability, par-ticularly in winter. The strongest intraseasonal variability ranges from 50 to 100 m with its maximum amplitude about 1.0-2.0℃. The subsurface temperature intraseasonal vari-ability in the SCS is primarily induced by local wind stress curl via adjusting the vertical displacement of thermocline. It reveals the important characteristic of intraseasonal varia-tions in the SCS upper ocean vertically.
基金This work was financially supported by the National Natural Science Foundation of China （30730061 ）, the National Basic Research Program of China （2009CB 119203）, andthe earmarked fund for Modem Agro-industry Technology Research System.
文摘Begomoviruses are exclusively transmitted by whitefly （Bemisia tabaci） in a circulative, non-propagative manner. The influences of begomoviruses on whitefly vector are complex with both direct and indirect effects. However, the molecular mechanisms underlying these effects are poorly understood and the transcriptional profiles of whitefly on healthy and virus-infected plants have not yet been studied. Using suppression subtractive hybridization, we investigated the differentially expressed genes in whitefly Middle East - Asia Minor 1 feeding on healthy and Tomato yellow leaf curl China virus （TYLCCNV） infected tobacco. From the forward cDNA library, 124 differentially expressed expression sequence tags （ESTs） were obtained which represent up-regulated genes in the whiteflies feeding on the infected tobacco. From the reverse library, 112 ESTs were isolated which represent down-regulated genes. Among the up-regulated genes, we identified several genes that are probably involved in direct interaction between whitefly and TYLCCN~, including a 26/29-kDa proteinase that appears to participate in the elimination of foreign proteins, heparan sulfate proteoglycan which mediates the entry of several viruses into host cells and two genes of Rickettsia-a secondary endosymbiotic bacterium of whitefly. In addition, we identified a number of genes involved in metabolism, transcription and translation which might be the result of indirect effects of TYLCCNV on the whitefly via host plants. Collectively, our results suggest that TYLCCNV-infected tobacco changes the gene expression profiles of whitefly via both direct and indirect interactions. This study revealed a number of genes involved in whitefly-TYLCCNV-tobacco interactions and provided useful information for future study on this complex system.
基金Supported by the State Key Basic Research and Development Plan of China (2006CB101903)the Fok Ying Tong Education Foundation(101032)+2 种基金the Cultivation Fund of the Key Scientific and Technical Innovation ProjectMinistry of Education of China(705025)the National Natural Science Foundation of China(30671352 and 30771406)
文摘Virus-induced gene silencing （VIGS） is a useful technique for rapid plant gene function analysis. We recently reported a new VIGS vector modified from Tomato yellow leaf curl China virus （TYLCCNV） DNAβ （DNAm β）. In this study we compared in detail DNAmβ-induced gene silencing in four Nicotiana species including N. benthamiana, N. glutinosa, N. tabacum and N. paniculata. We found that DNAmβ-induced gene silencing in the four species was distinct in developing dynamics, tissue specificity, efficiency, and constancy in the plant life span. It was most efficient in N. benthamiana, where development of VIGS was most rapid, without tissue specificity and nearly 100% efficient. DNAmβ-induced gene silencing in N. glutinosa was also efficient despite being slightly less than in N. benthamiana. It initially occurred in veins, later was scattered to mesophyll, finally led to complete silencing in whole leaves. In both species, VIGS constantly expressed until the plants died. However, DNAmβ-mediated VIGS in the other two Nicotiana species, N. tabacum and N. paniculata, was significantly less efficient. It was strictly limited within the veins of the silenced leaves, and constantly occurred only over 3-4 weeks. The upper leaves that emerged later stopped showing the silencing phenotype. DNAmβ-induced gene silencing in N. benthamiana and N. glutinosa was not significantly influenced by the growth stage when the plants were agro-inoculated, and was not sensitive to high growth temperature up to 32℃. Our results indicate that this system has great potential as a versatile VIGS system for routine functional analysis of genes in some Nicotiana species.
