The Experts below are selected from a list of 471258 Experts worldwide ranked by ideXlab platform
V G Malathi - One of the best experts on this subject based on the ideXlab platform.
-
infection of tomato leaf curl new delhi virus tolcndv a Bipartite Begomovirus with Betasatellites results in enhanced level of helper virus components and antagonistic interaction Between <B>DNAB> B and Betasatellites
Applied Microbiology and Biotechnology, 2013Co-Authors: P Jyothsna, Rob W Briddon, Q M I Haq, Priyanka Singh, K V Sumiya, Shelly Praveen, Ramaveer Rawat, V G MalathiAbstract:Tomato leaf curl New Delhi virus (ToLCNDV) (Geminiviridae) is an important pathogen that severely affects tomato production. An extensive survey was carried out during 2003–2010 to study the diversity of Begomoviruses found in tomato, potato, and cucurBits that showed symptoms of leaf puckering, distortion, curling, vein clearing, and yellow mosaic in various fields in different regions of India. Ten Begomovirus isolates were cloned from infected samples and identified as Belonging to the species ToLCNDV. A total of 44 % of the samples showed association of Betasatellites, with CLCuMuB and LuLDB Being the most frequent. The ToLCNDV cloned component <B>DNAB> A and <B>DNAB> B were agroinoculated on Nicotiana Benthamiana and tomato (Solanum lycopersicum) plants with or without Betasatellites, CLCuMuB or LuLDB. The viral genome levels were then monitored By real-time polymerase chain reaction at different time points of disease development. Plants co-inoculated with Betasatellites showed enhanced symptom severity in Both N. Benthamiana and tomato, as well as increases in helper viral <B>DNAB> A and <B>DNAB> B levels. The <B>DNAB> B and Betasatellites acted antagonistically to each other, so that the level of <B>DNAB> B was 16-fold greater in the presence of Betasatellites, while accumulation of Betasatellites, CLCuMuB and LuLDB, were reduced By 60 % in the presence of <B>DNAB> B. <B>DNAB> B-mediated symptoms predominated in CLCuMuB-inoculated plants, whereas Betasatellite-mediated leaf aBnormalities were prominent in LuLDB-co-inoculated plants. Inoculation with the cloned components will Be a good Biotechnological tool in resistance Breeding program.
-
Predominance of tomato leaf curl Gujarat virus as a monopartite Begomovirus: association with tomato yellow leaf curl Thailand Betasatellite.
Archives of virology, 2012Co-Authors: P Jyothsna, Ramaveer Rawat, V G MalathiAbstract:Tomato leaf curl is a serious malady in the state of Maharashtra, India, causing nearly 100 % yield loss. An extensive survey was done in the affected fields of tomato in the year 2008, and memBers of three species of Begomoviruses were identified as causing the disease. More than 60 % of the samples from diseased plants were infected with tomato leaf curl Gujarat virus (ToLCGuV). Isolates collected from these fields differed from the Varanasi isolate of ToLCGuV in not having a <B>DNAB> B component. Instead, they were like typical Old World monopartite Begomoviruses in that they were associated with only one Betasatellite, tomato yellow leaf curl Thailand Betasatellite (TYLCTHB). ToLCGuV alone is readily infectious, expressing systemic symptoms in Nicotiana Benthamiana and tomato. Co-inoculation of ToLCGuV with TYLCTHB, increased symptom severity and reduced the incuBation time required for symptom expression. ToLCGuV successfully interacted with heterologous <B>DNAB> B component of ToLCNDV [IN:Pun:JID:08], and co-inoculation of these two resulted in yellow mottling symptoms that were typical of <B>DNAB> B.
-
Cowpea golden mosaic disease in Gujarat is caused By a MungBean yellow mosaic India virus isolate with a <B>DNAB> B variant
Archives of virology, 2008Co-Authors: Pp John, Rob W Briddon, Q M I Haq, P. N. Sivalingam, N. Kumar, A. Mishra, V G MalathiAbstract:It has long Been assumed that cowpea golden mosaic disease (CGMD) in southern Asia is caused By a Begomovirus distinct from those causing disease in other legumes. The components of a Begomovirus causing CGMD in western India were isolated, cloned and sequenced. Analysis of the sequences shows the virus to Be an isolate of MungBean yellow mosaic India virus, But with a distinct <B>DNAB> B component with greater similarity to components of a second legume-infecting Begomovirus occurring in the region, MungBean yellow mosaic virus. The clones of the virus were readily infectious to cowpea, mungBean, Blackgram and French Bean By agroinoculation. However, the wild-type isolate was shown to Be easily transmissiBle By whiteflies Between cowpea plants But not to Blackgram and mugBean, suggesting that the insect vector plays a major role in determining the natural host range of these viruses.
-
characterisation of sri lankan cassava mosaic virus and indian cassava mosaic virus evidence for acquisition of a <B>DNAB> B component By a monopartite Begomovirus
Virology, 2002Co-Authors: Keith Saunders, N Salim, Vasant R Mali, V G Malathi, Rob W Briddon, P G Markham, John StanleyAbstract:ABstract Two Bipartite Begomoviruses, Indian cassava mosaic virus (ICMV) and Sri Lankan cassava mosaic virus (SLCMV), have Been isolated from mosaic-diseased cassava originating from central India and Sri Lanka, respectively. ICMV was transmitted with low efficiency from cassava to Nicotiana Benthamiana By sap inoculation to give leaf curl symptoms. SLCMV was much more virulent in this host, producing severe stunting, leaf curl, and chlorosis. These symptoms were reproduced when their cloned genomic components (<B>DNAB>s A and B) were introduced into N. Benthamiana By either mechanical or AgroBacterium -mediated inoculation (agroinoculation). SLCMV is more closely related to ICMV (<B>DNAB> A, 84%; <B>DNAB> B, 94% nucleotide identity) than African cassava mosaic virus (ACMV) (<B>DNAB> A, 74%; <B>DNAB> B, 47% nucleotide identity). Sequence comparisons suggest that SLCMV <B>DNAB> B originated from ICMV <B>DNAB> B By a recomBination event involving the SLCMV <B>DNAB> A intergenic region. PseudorecomBinants produced By reassortment of the cloned components of ICMV and ACMV were not infectious in N. Benthamiana, emphasising their status as distinct virus species. In contrast, a pseudorecomBinant Between ACMV <B>DNAB> A and SLCMV <B>DNAB> B was infectious. Consistent with these oBservations, iteron motifs located within the intergenic region that may Be involved in the initiation of viral <B>DNAB> replication are conserved Between SLCMV and ACMV But not ICMV. When introduced into N. Benthamiana By agroinoculation, SLCMV <B>DNAB> A alone produced a severe upward leaf roll symptom, reminiscent of the phenotype associated with some monopartite Begomoviruses. Furthermore, coinoculation of SLCMV <B>DNAB> A and the satellite <B>DNAB> β associated with ageratum yellow vein virus (AYVV) produced severe downward leaf curl in N. glutinosa and yellow vein symptoms in Ageratum conyzoides, resemBling the phenotypes associated with AYVV <B>DNAB> A and <B>DNAB> β infection in these hosts. Thus, SLCMV <B>DNAB> A has Biological characteristics of a monopartite Begomovirus, and the virus proBaBly evolved By acquisition of a <B>DNAB> B component from ICMV.
-
Putative Location of Common Region and Coat Protein Gene of Blackgram Isolate of MungBean Yellow Mosaic Geminivirus
Journal of Plant Biochemistry and Biotechnology, 1998Co-Authors: Anupam Varma, Bikash Mandal, V G MalathiAbstract:Reciprocal cross hyBridization Between <B>DNAB>-A and ONA-B molecules showed that MYMV genome contains certain regions common to each other. “Common region” of MYMV Belongs to the 0.55 kB Kpnl-Clal fragment of <B>DNAB>-A and 0.25 kB XBal-Hind III fragment of <B>DNAB>-B. HyBridization of <B>DNAB>-A restriction fragments with the full length coat protein region proBe to Indian cassava mosaic virus (ICMV) showed the location of MYMV coat protein coding region in <B>DNAB>-A. The greater extent of homology of ICMV coat protein region falls within the 400 Base pair region of Clal-Clal fragment in <B>DNAB>-A of MYMV-Bg. The homology Between ICMV and MYMV-Bg coat protein gene appeared to Be less than 50%. Cross hyBridization Between <B>DNAB>-A and <B>DNAB>-B molecules helped to trim out the homologous region and the <B>DNAB>-A and <B>DNAB>-B specific proBes could Be tailored.
E Maiss - One of the best experts on this subject based on the ideXlab platform.
-
Transreplication of a Tomato yellow leaf curl Thailand virus <B>DNAB>-B and replication of a <B>DNAB>Beta component By Tomato leaf curl Vietnam virus and Tomato yellow leaf curl Vietnam virus.
Virus research, 2008Co-Authors: R Blawid, D T Van, E MaissAbstract:The genomes of two tomato-infecting Begomoviruses from Vietnam were cloned and sequenced. A new variant of Tomato leaf curl Vietnam virus (ToLCVV) consisting of a <B>DNAB>-A component and associated with a <B>DNAB>Beta molecule as well as an additional Begomovirus tentatively named Tomato yellow leaf curl Vietnam virus (TYLCVV) consisting also of a <B>DNAB>-A component were identified. To verify if monopartite viruses occurring in Vietnam and Thailand are aBle to transreplicate the <B>DNAB>-B component of Tomato yellow leaf curl Thailand virus-[Asian Institute of Technology] (TYLCTHV-[AIT]) infectivity assays were performed via agroinoculation and mechanically. As result, the <B>DNAB>-B component of TYLCTHV-[AIT] was transreplicated By different <B>DNAB>-A components of viruses from Vietnam and Thailand in Nicotiana Benthamiana and Solanum lycopersicum. Moreover, the TYLCTHV-[AIT] <B>DNAB>-B component facilitated the mechanical transmission of monopartite viruses By ruB-inoculation as well as By particle BomBardment in N. Benthamiana and tomato plants. Finally, defective <B>DNAB>s ranging from 735 to 1457 nucleotides were generated in N. Benthamiana from those comBinations containing TYLCTHV-[AIT] <B>DNAB>-B component.
-
Transreplication of a Tomato yellow leaf curl Thailand virus <B>DNAB>-B and replication of a <B>DNAB>ß component By Tomato leaf curl Vietnam virus and Tomato yellow leaf curl Vietnam virus
Virus Research, 2008Co-Authors: R Blawid, D T Van, E MaissAbstract:ABstract The genomes of two tomato-infecting Begomoviruses from Vietnam were cloned and sequenced. A new variant of Tomato leaf curl Vietnam virus (ToLCVV) consisting of a <B>DNAB>-A component and associated with a <B>DNAB>s molecule as well as an additional Begomovirus tentatively named Tomato yellow leaf curl Vietnam virus (TYLCVV) consisting also of a <B>DNAB>-A component were identified. To verify if monopartite viruses occurring in Vietnam and Thailand are aBle to transreplicate the <B>DNAB>-B component of Tomato yellow leaf curl Thailand virus —[Asian Institute of Technology] (TYLCTHV-[AIT]) infectivity assays were performed via agroinoculation and mechanically. As result, the <B>DNAB>-B component of TYLCTHV-[AIT] was transreplicated By different <B>DNAB>-A components of viruses from Vietnam and Thailand in Nicotiana Benthamiana and Solanum lycopersicum . Moreover, the TYLCTHV-[AIT] <B>DNAB>-B component facilitated the mechanical transmission of monopartite viruses By ruB-inoculation as well as By particle BomBardment in N. Benthamiana and tomato plants. Finally, defective <B>DNAB>s ranging from 735 to 1457 nucleotides were generated in N. Benthamiana from those comBinations containing TYLCTHV-[AIT] <B>DNAB>-B component.
Rob W Briddon - One of the best experts on this subject based on the ideXlab platform.
-
infection of tomato leaf curl new delhi virus tolcndv a Bipartite Begomovirus with Betasatellites results in enhanced level of helper virus components and antagonistic interaction Between <B>DNAB> B and Betasatellites
Applied Microbiology and Biotechnology, 2013Co-Authors: P Jyothsna, Rob W Briddon, Q M I Haq, Priyanka Singh, K V Sumiya, Shelly Praveen, Ramaveer Rawat, V G MalathiAbstract:Tomato leaf curl New Delhi virus (ToLCNDV) (Geminiviridae) is an important pathogen that severely affects tomato production. An extensive survey was carried out during 2003–2010 to study the diversity of Begomoviruses found in tomato, potato, and cucurBits that showed symptoms of leaf puckering, distortion, curling, vein clearing, and yellow mosaic in various fields in different regions of India. Ten Begomovirus isolates were cloned from infected samples and identified as Belonging to the species ToLCNDV. A total of 44 % of the samples showed association of Betasatellites, with CLCuMuB and LuLDB Being the most frequent. The ToLCNDV cloned component <B>DNAB> A and <B>DNAB> B were agroinoculated on Nicotiana Benthamiana and tomato (Solanum lycopersicum) plants with or without Betasatellites, CLCuMuB or LuLDB. The viral genome levels were then monitored By real-time polymerase chain reaction at different time points of disease development. Plants co-inoculated with Betasatellites showed enhanced symptom severity in Both N. Benthamiana and tomato, as well as increases in helper viral <B>DNAB> A and <B>DNAB> B levels. The <B>DNAB> B and Betasatellites acted antagonistically to each other, so that the level of <B>DNAB> B was 16-fold greater in the presence of Betasatellites, while accumulation of Betasatellites, CLCuMuB and LuLDB, were reduced By 60 % in the presence of <B>DNAB> B. <B>DNAB> B-mediated symptoms predominated in CLCuMuB-inoculated plants, whereas Betasatellite-mediated leaf aBnormalities were prominent in LuLDB-co-inoculated plants. Inoculation with the cloned components will Be a good Biotechnological tool in resistance Breeding program.
-
Infectious clones of Tomato leaf curl Palampur virus with a defective <B>DNAB> B and their pseudo-recomBination with Tomato leaf curl New Delhi virus.
Virology journal, 2011Co-Authors: Aamir Humayun Malik, Rob W Briddon, Shahid MansoorAbstract:Background: Tomato leaf curl Palampur virus (ToLCPMV) is a Bipartite Begomovirus which has Been reported from India and Iran But infectious clones have not Been oBtained. We have previously shown the association of Zucchini yellow mosaic virus (ZYMV), a potyvirus, with severe leaf curl disease of muskmelon in Pakistan. However, the severity of symptoms in the field and yield losses led us to Believe that some other agent, such as a Begomovirus, could Be associated with the disease. Results: A Bipartite Begomovirus associated with a severe yellow leaf curl disease on muskmelon in Pakistan has Been characterized. Analysis of the complete nucleotide sequence of the <B>DNAB> A and <B>DNAB> B components of the Begomovirus showed that it has the highest <B>DNAB> sequence identity with ToLCPMV. However, the gene encoding the nuclear shuttle protein (NSP) was truncated in comparison to previously characterised isolates. AgroBacteriummediated inoculation of Nicotiana Benthamiana with the ToLCPMV clones oBtained here did not result in symptoms. However, inoculation of plants with the <B>DNAB> A component of ToLCPMV and the <B>DNAB> B component of Tomato leaf curl New Delhi virus (ToLCNDV) lead to systemic infection with leaf curl symptoms. This suggested that the lack of infectivity of the ToLCPMV clones was due to the defect in <B>DNAB> B. The <B>DNAB> B of ToLCPMV was aBle to move systemically when inoculated with <B>DNAB> A of the either virus. Agro-infiltration of muskmelon with the <B>DNAB> A and <B>DNAB> B components of ToLCPMV did not lead to symptomatic infection whereas inoculation with the <B>DNAB> A with the <B>DNAB> B of ToLCNDV resulted in a hypersensitive response (HR) along the veins. Additionally, agroinfiltration of muskmelon with a construct for the expression of the NSP gene of ToLCNDV under the control of the cauliflower mosaic virus 35S promoter induced a HR, suggesting that this is the gene causing the HR. Conclusions: Both ToLCPMV and ZYMV are associated with muskmelon leaf curl disease in Pakistan. However, the ToLCPMV variant identified in association with ZYMV has a defective NSP. The results suggest that a variant with a defective NSP may have Been selected for in muskmelon, as this protein is an avirulence determinant in this species, and possiBly that infection requires the synergistic interaction with ZYMV.
-
pepper leaf curl lahore virus requires the <B>DNAB> B component of tomato leaf curl new delhi virus to cause leaf curl symptoms
Virology Journal, 2010Co-Authors: Muhammad Shafiq, Rob W Briddon, Shaheen Asad, Yusuf Zafar, Shahid MansoorAbstract:Background Begomoviruses are whitefly-transmitted geminiviruses with genomes that consist of either two components (known as <B>DNAB> A and <B>DNAB> B) or a single component (homologous to the <B>DNAB> A component of Bipartite Begomoviruses). Monopartite Begomoviruses are often associated with a symptom-modulating <B>DNAB> satellite (collectively known as Betasatellites). Both Bipartite and monopartite Begomoviruses with associated satellites have previously Been identified in chillies showing leaf curl symptoms in Pakistan.
-
Distinct evolutionary histories of the <B>DNAB>-A and <B>DNAB>-B components of Bipartite Begomoviruses.
BMC evolutionary biology, 2010Co-Authors: Rob W Briddon, Basavaprabhu L. Patil, Basavaraj Bagewadi, Muhammad Shah Nawaz-ul-rehman, Claude M. FauquetAbstract:Viruses of the genus Begomovirus (family Geminiviridae) have genomes consisting of either one or two genomic components. The component of Bipartite Begomoviruses known as <B>DNAB>-A is homologous to the genomes of all geminiviruses and encodes proteins required for replication, control of gene expression, overcoming host defenses, encapsidation and insect transmission. The second component, referred to as <B>DNAB>-B, encodes two proteins with functions in intra- and intercellular movement in host plants. The origin of the <B>DNAB>-B component remains unclear. The study descriBed here was initiated to investigate the relationship Between the <B>DNAB>-A and <B>DNAB>-B components of Bipartite Begomoviruses with a view to unraveling their evolutionary histories and providing information on the possiBle origin of the <B>DNAB>-B component. Comparative phylogenetic and exhaustive pairwise sequence comparison of all <B>DNAB>-A and <B>DNAB>-B components of Begomoviruses demonstrates that the two molecules have very distinct molecular evolutionary histories and likely are under very different evolutionary pressures. The analysis highlights that component exchange has played a far greater role in diversification of Begomoviruses than previously suspected, although there are distinct differences in the apparent aBility of different groups of viruses to utilize this "sexual" mechanism of genetic exchange. Additionally we explore the hypothesis that <B>DNAB>-B originated as a satellite that was captured By the monopartite progenitor of all extant Bipartite Begomoviruses and suBsequently evolved to Become the integral (essential) genome component that we recognize today. The situation with present-day satellites associated with Begomoviruses provides some clues to the processes and selection pressures that may have led to the "domestication" of a wild progenitor of the <B>DNAB>-B component. The analysis has highlighted the greater genetic variation of <B>DNAB>-B components, in comparison to the <B>DNAB>-A components, and that component exchange is more widespread than previously demonstrated and confined to viruses from the Old World. Although the vast majority of New World and some Old World Begomoviruses show near perfect co-evolution of the <B>DNAB>-A and <B>DNAB>-B components, this is not the case for the majority of Old World viruses. Genetic differences Between Old and New World Begomoviruses and the cultivation of exotic crops in the Old World are likely factors that have led to this dichotomy.
-
Cowpea golden mosaic disease in Gujarat is caused By a MungBean yellow mosaic India virus isolate with a <B>DNAB> B variant
Archives of virology, 2008Co-Authors: Pp John, Rob W Briddon, Q M I Haq, P. N. Sivalingam, N. Kumar, A. Mishra, V G MalathiAbstract:It has long Been assumed that cowpea golden mosaic disease (CGMD) in southern Asia is caused By a Begomovirus distinct from those causing disease in other legumes. The components of a Begomovirus causing CGMD in western India were isolated, cloned and sequenced. Analysis of the sequences shows the virus to Be an isolate of MungBean yellow mosaic India virus, But with a distinct <B>DNAB> B component with greater similarity to components of a second legume-infecting Begomovirus occurring in the region, MungBean yellow mosaic virus. The clones of the virus were readily infectious to cowpea, mungBean, Blackgram and French Bean By agroinoculation. However, the wild-type isolate was shown to Be easily transmissiBle By whiteflies Between cowpea plants But not to Blackgram and mugBean, suggesting that the insect vector plays a major role in determining the natural host range of these viruses.
R Blawid - One of the best experts on this subject based on the ideXlab platform.
-
Transreplication of a Tomato yellow leaf curl Thailand virus <B>DNAB>-B and replication of a <B>DNAB>Beta component By Tomato leaf curl Vietnam virus and Tomato yellow leaf curl Vietnam virus.
Virus research, 2008Co-Authors: R Blawid, D T Van, E MaissAbstract:The genomes of two tomato-infecting Begomoviruses from Vietnam were cloned and sequenced. A new variant of Tomato leaf curl Vietnam virus (ToLCVV) consisting of a <B>DNAB>-A component and associated with a <B>DNAB>Beta molecule as well as an additional Begomovirus tentatively named Tomato yellow leaf curl Vietnam virus (TYLCVV) consisting also of a <B>DNAB>-A component were identified. To verify if monopartite viruses occurring in Vietnam and Thailand are aBle to transreplicate the <B>DNAB>-B component of Tomato yellow leaf curl Thailand virus-[Asian Institute of Technology] (TYLCTHV-[AIT]) infectivity assays were performed via agroinoculation and mechanically. As result, the <B>DNAB>-B component of TYLCTHV-[AIT] was transreplicated By different <B>DNAB>-A components of viruses from Vietnam and Thailand in Nicotiana Benthamiana and Solanum lycopersicum. Moreover, the TYLCTHV-[AIT] <B>DNAB>-B component facilitated the mechanical transmission of monopartite viruses By ruB-inoculation as well as By particle BomBardment in N. Benthamiana and tomato plants. Finally, defective <B>DNAB>s ranging from 735 to 1457 nucleotides were generated in N. Benthamiana from those comBinations containing TYLCTHV-[AIT] <B>DNAB>-B component.
-
Transreplication of a Tomato yellow leaf curl Thailand virus <B>DNAB>-B and replication of a <B>DNAB>ß component By Tomato leaf curl Vietnam virus and Tomato yellow leaf curl Vietnam virus
Virus Research, 2008Co-Authors: R Blawid, D T Van, E MaissAbstract:ABstract The genomes of two tomato-infecting Begomoviruses from Vietnam were cloned and sequenced. A new variant of Tomato leaf curl Vietnam virus (ToLCVV) consisting of a <B>DNAB>-A component and associated with a <B>DNAB>s molecule as well as an additional Begomovirus tentatively named Tomato yellow leaf curl Vietnam virus (TYLCVV) consisting also of a <B>DNAB>-A component were identified. To verify if monopartite viruses occurring in Vietnam and Thailand are aBle to transreplicate the <B>DNAB>-B component of Tomato yellow leaf curl Thailand virus —[Asian Institute of Technology] (TYLCTHV-[AIT]) infectivity assays were performed via agroinoculation and mechanically. As result, the <B>DNAB>-B component of TYLCTHV-[AIT] was transreplicated By different <B>DNAB>-A components of viruses from Vietnam and Thailand in Nicotiana Benthamiana and Solanum lycopersicum . Moreover, the TYLCTHV-[AIT] <B>DNAB>-B component facilitated the mechanical transmission of monopartite viruses By ruB-inoculation as well as By particle BomBardment in N. Benthamiana and tomato plants. Finally, defective <B>DNAB>s ranging from 735 to 1457 nucleotides were generated in N. Benthamiana from those comBinations containing TYLCTHV-[AIT] <B>DNAB>-B component.
John Stanley - One of the best experts on this subject based on the ideXlab platform.
-
Deletion and recomBination events Between the <B>DNAB>-A and <B>DNAB>-B components of Indian cassava-infecting geminiviruses generate defective molecules in Nicotiana Benthamiana.
Virus research, 2006Co-Authors: Basavaprabhu L. Patil, Rob W Briddon, John Stanley, Nitin Dutt, S. E. Bull, Dirk Rothenstein, Basanta K. Borah, Indranil Dasgupta, Holger JeskeAbstract:Cloned <B>DNAB>-B components, Belonging to the Bipartite Begomoviruses Indian cassava mosaic virus (ICMV) and Sri Lankan cassava mosaic virus (SLCMV), family Geminiviridae, when co-inoculated along with previously cloned <B>DNAB>-A components of the respective viruses onto the experimental host Nicotiana Benthamiana, generated defective <B>DNAB>s (def-<B>DNAB>) ranging in size from 549 to 1555 nucleotides. All the cloned def-<B>DNAB>s contained the common region (CR) as well as portions of either <B>DNAB>-A or <B>DNAB>-B and, in a few cases, Both <B>DNAB>-A and <B>DNAB>-B, representing recomBinant products, the junction points of which correspond to repeats of 2-11 Bases found in the parental molecules. The <B>DNAB>-B-derived def-<B>DNAB>s were, in some cases, associated with a decrease in levels of <B>DNAB>-B, with a concomitant change in the symptoms from downward leaf curling in the older leaves to upward leaf-rolling in newly emerging leaves, more typical of monopartite Begomoviruses.
-
characterisation of sri lankan cassava mosaic virus and indian cassava mosaic virus evidence for acquisition of a <B>DNAB> B component By a monopartite Begomovirus
Virology, 2002Co-Authors: Keith Saunders, N Salim, Vasant R Mali, V G Malathi, Rob W Briddon, P G Markham, John StanleyAbstract:ABstract Two Bipartite Begomoviruses, Indian cassava mosaic virus (ICMV) and Sri Lankan cassava mosaic virus (SLCMV), have Been isolated from mosaic-diseased cassava originating from central India and Sri Lanka, respectively. ICMV was transmitted with low efficiency from cassava to Nicotiana Benthamiana By sap inoculation to give leaf curl symptoms. SLCMV was much more virulent in this host, producing severe stunting, leaf curl, and chlorosis. These symptoms were reproduced when their cloned genomic components (<B>DNAB>s A and B) were introduced into N. Benthamiana By either mechanical or AgroBacterium -mediated inoculation (agroinoculation). SLCMV is more closely related to ICMV (<B>DNAB> A, 84%; <B>DNAB> B, 94% nucleotide identity) than African cassava mosaic virus (ACMV) (<B>DNAB> A, 74%; <B>DNAB> B, 47% nucleotide identity). Sequence comparisons suggest that SLCMV <B>DNAB> B originated from ICMV <B>DNAB> B By a recomBination event involving the SLCMV <B>DNAB> A intergenic region. PseudorecomBinants produced By reassortment of the cloned components of ICMV and ACMV were not infectious in N. Benthamiana, emphasising their status as distinct virus species. In contrast, a pseudorecomBinant Between ACMV <B>DNAB> A and SLCMV <B>DNAB> B was infectious. Consistent with these oBservations, iteron motifs located within the intergenic region that may Be involved in the initiation of viral <B>DNAB> replication are conserved Between SLCMV and ACMV But not ICMV. When introduced into N. Benthamiana By agroinoculation, SLCMV <B>DNAB> A alone produced a severe upward leaf roll symptom, reminiscent of the phenotype associated with some monopartite Begomoviruses. Furthermore, coinoculation of SLCMV <B>DNAB> A and the satellite <B>DNAB> β associated with ageratum yellow vein virus (AYVV) produced severe downward leaf curl in N. glutinosa and yellow vein symptoms in Ageratum conyzoides, resemBling the phenotypes associated with AYVV <B>DNAB> A and <B>DNAB> β infection in these hosts. Thus, SLCMV <B>DNAB> A has Biological characteristics of a monopartite Begomovirus, and the virus proBaBly evolved By acquisition of a <B>DNAB> B component from ICMV.
-
Detection and possiBle functions of African cassava mosaic virus <B>DNAB> B gene products.
Virology, 1993Co-Authors: Albrecht G Von Arnim, Thomas Frischmuth, John StanleyAbstract:ABstract Polyclonal antisera raised against synthetic oligopeptides have Been used to detect the <B>DNAB> B gene products BV1 and BC1 of the geminivirus African cassava mosaic virus following SDS-PAGE fractionation of Nicotiana Benthamiana extracts. BV1 antiserum detected a soluBle protein of 29 kDa, consistent with the size predicted from sequence data. BC1 antiserum detected proteins of 37, 39, and 42 kDa in addition to variaBle, less aBundant species, all of which are larger than the predicted size of 34 kDa. BC1 antiserum detected a single protein of 35-36 kDa following in vitro translation in reticulocyte lysate, suggesting that BC1 is post-translationally modified in plants. The nature of the modification was not resolved, although neither glycosylation nor association with nucleic acids is involved. In common with putative spread proteins of several other plant viruses, BC1 cofractionated with the cell wall. The replication of Both genomic components in N. taBacum protoplasts was unaffected By the introduction of frameshift mutations into BV1 and BC1 coding regions. In inoculated N. Benthamiana leaves, however, the accumulation of a BV1 mutant was significantly reduced compared to the levels attained By co-inoculated, complementing BV1 and BC1 mutants. In contrast, the accumulation of a BC1 mutant was unaffected, although symptom induction in inoculated leaves and systemic infection occurred only in the presence of Both BV1 and BC1. The results are consistent with a role for BV1 in localized celt-to-cell spread and for BC1, possiBly together with BV1, in long-distance vascular spread of the virus.
-
determinants of tomato golden mosaic virus symptom development located on <B>DNAB> B
Virology, 1992Co-Authors: Albrecht G Von Arnim, John StanleyAbstract:Infectious clones have Been constructed from two strains of the Bipartite geminivirus tomato golden mosaic virus. The common strain and the yellow vein strain show marked phenotypic differences in Nicotiana Benthamiana which are reproduced following infection with the cloned viral genomes. PseudorecomBinants Between the two strains, produced By exchange of genome components (<B>DNAB>s A and B), estaBlished that the difference in symptoms in several species of the Solanaceae is determined By <B>DNAB> B. RecomBinants produced in vitro Between the <B>DNAB> B components showed that determinants of symptom development map to the common region and gene BL1. <B>DNAB> B is known to carry functions necessary for spread of viral <B>DNAB> through the host plant. Our results emphasize the link Between symptom type and virus spread.