scholarly journals Association of a Monopartite Begomovirus Producing Subgenomic DNA and a Distinct DNA Beta on Croton bonplandianus Showing Yellow Vein Symptoms in Pakistan

Plant Disease ◽  
2002 ◽  
Vol 86 (4) ◽  
pp. 444-444 ◽  
Author(s):  
I. Amin ◽  
S. Mansoor ◽  
S. Iram ◽  
M. A. Khan ◽  
M. Hussain ◽  
...  

The recent discovery that monopartite begomoviruses on ageratum and cotton essentially require a DNA satellite called DNA β (2,4) is leading to identification of several other hosts that have similar disease complexes. A weed species (Croton bonplandianus) belonging to the family Euphorbiaceae is one such example. C. bonplandianus is widely distributed on wastelands throughout the Punjab Province in Pakistan. It very often shows yellow vein symptoms indicating infection by a begomovirus. To detect a begomovirus, both symptomatic and asymptomatic plants were collected from several widely separated locations in the Punjab Province. Total DNA was isolated from these samples by the cetyltrimethylammoniumbromide (CTAB) method, resolved in an agarose gel, and blotted on a nylon membrane (2). A full-length clone of DNA A of Cotton leaf curl virus (CLCuV) labeled with 32PdCTP was used as a probe in Southern hybridization (2). The probe detected hybridizing bands only in symptomatic plants, confirming the presence of a begomovirus. In addition to hybridizing bands of the expected sizes, smaller bands were also detected, suggesting the presence of subgenomic molecules derived from DNA A. Universal polymerase chain reaction (PCR) primers for dicot-infecting geminiviruses (1) were used in PCR for amplification of DNA A of the begomovirus associated with the disease. The use of these primers in PCR was expected to result in amplification of full-length DNA A. In addition to a product of the expected size (2.7 to 2.8 kb), another product of approximately 1.4 kb was amplified. The presence of subgenomic DNAs that are derived from DNA A is an indicator of the monopartite nature of begomoviruses, because in bipartite begomoviruses subgenomic DNAs are derived solely from DNA B. The presence of a DNA β, a DNA satellite associated with certain monopartite begomoviruses, was suspected because of symptoms and the possible monopartite nature of the virus. Universal primers for amplification of DNA β (3) were used in PCR for amplification of a putative DNA β. The PCR reaction yielded a product of expected size (≈1.4 kb). A probe from the amplified product was made by the oligolabeling method. The probe detected hybridizing bands in all symptomatic samples collected from three locations, confirming the association of a DNA β with the disease. A duplicate blot when hybridized with a DNA β associated with ageratum yellow vein disease did not hybridize to these samples. These results confirm that yellow vein disease on this weed is associated with a monopartite begomovirus and a distinct DNA β. References: (1) R. W. Briddon et al. Mol. Biotechnol. 1:202, 1994. (2) R. W. Briddon et al. Virology 285:234, 2001. (3) R. W. Briddon et al. Mol. Biotechnol. In press. (4) K. Saunders et al. Proc. Natl. Acad. Sci. U S A 97:6890, 2000.

Plant Disease ◽  
2000 ◽  
Vol 84 (7) ◽  
pp. 809-809 ◽  
Author(s):  
S. Mansoor ◽  
S. Mukhtar ◽  
M. Hussain ◽  
I. Amin ◽  
Y. Zafar ◽  
...  

The current epidemic of cotton leaf curl disease (CLCuD) in Pakistan started in 1988 with the natural host range limited to a few plant species in the family Malvaceae. However, we have observed expansion in the host range of the virus, and several non-Malvaceous plants were found to be infected with the virus. Characteristic symptoms of CLCuD such as leaf curl and enations have been observed on radish plants, primarily in kitchen gardens. However, in 1999, levels of infection of 10 to 90% were observed both in commercial fields and kitchen gardens in the Punjab province of Pakistan. Both symptomatic and nonsymptomatic samples were collected from five different locations. Total DNA was isolated, dot-blotted on nylon membrane, and a full-length clone corresponding to DNA A of cotton leaf curl virus was labeled with 32P dCTP and used as a probe for the detection of a begomovirus. Strong signals were observed in symptomatic plants while no signals were observed in nonsymptomatic plants. Infection with a begomovirus was further confirmed by polymerase chain reaction (PCR) using degenerate primers for DNA A (1). Primers specific for the two distinct begomoviruses associated with CLCuD were also used in PCR reactions (2), and products of the expected size were obtained from all symptomatic samples, confirming infection with begomoviruses similar to those associated with CLCuD. A full-length probe of a nanovirus-like molecule associated with cotton leaf disease (3), called DNA 1 was labeled with 32P dCTP and detected the virus only in symptomatic plants. Similarly, primers specific for DNA 1 (3) amplified a product of expected size when used in PCR. On the basis of symptomatology and the detection of specific viral components associated with the disease, we confirmed that radish plants are infected with Cotton leaf curl virus (CLCuV). Since radish is a short duration crop, infection of CLCuV in radish may not serve as a direct source of infection for the next cotton crop. However, it is a potential threat to tomato crops which overlap with radish in the Punjab province. The detection of CLCuD in radish is another example of the mobilization of begomoviruses to previously unknown hosts. References: (1) M. R. Rojas et al. Plant Dis. 77:340, 1993. (2) S. Mansoor et al. Pak. J. Bot. 31:115, 1999. (3) Mansoor et al. Virology 259:190, 1999.


Plant Disease ◽  
2000 ◽  
Vol 84 (1) ◽  
pp. 101-101 ◽  
Author(s):  
S. Mansoor ◽  
S. H. Khan ◽  
M. Hussain ◽  
Y. Zafar ◽  
M. S. Pinner ◽  
...  

Whitefly-transmitted geminiviruses (begomoviruses) cause heavy losses to many food and fiber crops in Pakistan. Many weeds also show symptoms typical of begomoviruses. Ageratum (Ageratum conyzoides) is a common perennial weed in Pakistan, growing along irrigation canals, that often shows symptoms, such as yellow vein and mosaic, suggesting infection by a begomovirus. To confirm this, symptomatic and asymptomatic ageratum plants were collected from three locations in the Punjab Province of Pakistan, and total DNA was isolated, subjected to agarose gel electrophoresis, transferred to a nylon membrane, and Southern blotted. Total DNA isolated from cotton infected with Cotton leaf curl virus (CLCuV), tomato infected with Tomato leaf curl virus from Pakistan (TLCV-Pak), tobacco infected with African cassava mosaic virus (ACMV) from Nigeria, and healthy tobacco were included as controls. A full-length clone of CLCuV DNA A was labeled with [32P]dCTP by oligo-labeling and hybridized at medium stringency. The probe detected characteristic geminivirus DNA forms in symptomatic ageratum and plants infected with CLCuV, TLCV-Pak, and ACMV, while no signal was detected in asymptomatic ageratum from the field or healthy tobacco. To confirm infection by a begomovirus, degenerate primers WTGF (5′-GATTGTACGCGTCCDCCTTTAATTT GAAYBGG-3′), designed in the rep gene of begomoviruses, and WTGR (5′-TANACGCGTGGC TTCKRTACATGGCCTDT-3′), designed in the coat protein gene of DNA A of begomoviruses, were used in polymerase chain reaction (PCR). Degenerate primers (PBLv2040 and PCRc1) also were used in PCR (2). A product of expected size (≈1.4 kb) was obtained with DNA A primers from symptomatic ageratum, while no product was obtained with DNA B primers in the same sample. Previously we were unable to detect a DNA component equivalent to begomovirus DNA B in cotton showing symptoms of cotton leaf curl disease (1). We recently reported a novel circular DNA molecule that was approximately half as long as the full-length DNA A (CLCuV DNA-1) associated with CLCuV that share homology to plant nanoviruses (1). The supercoiled replicative form of viral DNA isolated from infected ageratum plants indicated the presence of smaller molecules, as was found in cotton leaf curl disease, suggesting that a nanovirus-like molecule might be associated with ageratum yellow vein disease. A duplicate blot of samples used in Southern hybridization with the DNA A probe was prepared, and a probe of the full-length clone of the nanovirus-like molecule (CLCuV DNA-1) was prepared as described for DNA A. The probe detected characteristic nanovirus DNA forms in ageratum with yellow vein symptoms and cotton infected with CLCuV, while no signal was detected in plants infected with TLCV-Pak or ACMV, healthy tobacco, or asymptomatic ageratum. Abutting primers PB2-F and PB2R (1), designed based on the CLCuV DNA-1 sequence, were unable to amplify a PCR product from ageratum with yellow vein symptoms, suggesting the nanovirus-like molecule associated with ageratum yellow vein disease is distinct from CLCuV DNA-1. Our results show that yellow vein disease of ageratum in Pakistan is associated with a begomovirus infection and single-stranded circular DNA molecule with similarity to CLCuV DNA-1. References: (1) S. Mansoor et al. Virology 259:190, 1999. (2) M. R. Rojas et al., Plant Dis. 77:340, 1993.


2021 ◽  
Author(s):  
Yafei Tang ◽  
Zhenggang Li ◽  
Xiaoman She ◽  
Lin Yu ◽  
Guobing Lan ◽  
...  

Abstract A previously undescribed monopartite begomovirus was identified from Malvastrum coromandelianum plants exhibiting yellow vein symptoms characteristic of begomoviruses, in Kampot province, Cambodia. The apparently full-length viral component was cloned and sequenced following enrichment of circular DNA by rolling circle amplification and restriction enzyme digestion. The genome of the virus was 2,737 nucleotides in length (KP188831), and exhibited an organization like that of other monopartite begomoviruses, sharing the highest nt identities of 87.7% with Ageratum yellow vein virus (AM940137). A satellite molecule was amplified from total DNA by PCR amplification with the betasatellite-specific primer pair β01/β02. The satellite molecule (1,346 nt, KP188832) had a structure characteristic like other betasatellites associated with begomoviruses, and shared the highest nt identity of 84.8% with Malvastrum yellow vein betasatellite (MN205547). According to the criteria established for species demarcation for classification of begomoviruses ( Geminiviridae ) and betasatellites ( Tolecusatellitidae ), respectively, the virus isolate from M. coromandelianum in Cambodia is a previously undescribed novel monopartite begomovirus species,for which the name Malvastrum yellow vein Cambodia virus (MaYVCV) is proposed, whereas, the betasatellite is identified as an previously undescribed novel betasatellite species, for which the name Malvastrum yellow vein Cambodia batesatellite (MaYVKHB) is proposed.


2008 ◽  
Vol 89 (12) ◽  
pp. 3165-3172 ◽  
Author(s):  
Keith Saunders ◽  
Rob W. Briddon ◽  
John Stanley

Pseudorecombination studies in Nicotiana benthamiana demonstrate that Ageratum yellow vein virus (AYVV) and Eupatorium yellow vein virus (EpYVV) can functionally interact with DNA-β satellites associated with AYVV, EpYVV, cotton leaf curl Multan virus (CLCuMV) and honeysuckle yellow vein virus (HYVV). In contrast, CLCuMV shows some specificity in its ability to interact with distinct satellites and HYVV is able to interact only with its own satellite. Using an N. benthamiana leaf disk assay, we have demonstrated that HYVV is unable to trans-replicate other satellites. To investigate the basis of trans-replication compatibility, deletion mutagenesis of AYVV DNA-β has been used to localize the origin of replication to approximately 360 nt, encompassing the ubiquitous nonanucleotide/stem–loop structure, satellite conserved region (SCR) and part of the intergenic region immediately upstream of the SCR. Additional deletions within this intergenic region have identified a region that is essential for replication. The capacity for DNA-β satellites to functionally interact with distinct geminivirus species and its implications for disease diversification are discussed.


2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Muhammad Shafiq Shahid ◽  
Muhammad Shafiq ◽  
Amir Raza ◽  
Abdullah M. Al-Sadi ◽  
Rob W. Briddon

Abstract Background In Oman tobacco (Nicotiana tabacum; family Solanaceae) is a minor crop, which is produced only for local consumption. In 2015, tobacco plants exhibiting severe downward leaf curling, leaf thickening, vein swelling, yellowing and stunting were identified in fields of tobacco in Suhar Al-Batina region, Oman. These symptoms are suggestive of begomovirus (genus Begomovirus, family Geminiviridae) infection. Methods Circular DNA molecules were amplified from total DNA extracted from tobacco plants by rolling circle amplification (RCA). Viral genomes were cloned from RCA products by restriction digestion and betasatellites were cloned by PCR amplification from RCA product, using universal primers. The sequences of full-length clones were obtained by Sanger sequencing and primer walking. Constructs for the infectivity of virus and betasatellite were produced and introduced into plants by Agrobacterium-mediated inoculation. Results The full-length sequences of 3 begomovirus and 3 betasatellite clones, isolated from 3 plants, were obtained. Analysis of the full-length sequences determined showed the virus to be a variant of Chilli leaf curl virus (ChiLCV) and the betasatellite to be a variant of Tomato leaf curl betasatellite (ToLCB). Both the virus and the betasatellite isolated from tobacco show the greatest levels of sequence identity to isolates of ChiLCV and ToLCB identified in other hosts in Oman. Additionally clones of ChiLCV and ToLCB were shown, by Agrobacterium-mediated inoculation, to be infectious to 3 Nicotiana species, including N. tabacum. In N. benthamiana the betasatellite was shown to change the upward leaf rolling symptoms to a severe downward leaf curl, as is typical for many monopartite begomoviruses with betasatellites. Conclusions The leaf curl disease of tobacco in Oman was shown to be caused by ChiLCV and ToLCB. This is the first identification of ChiLCV with ToLCB infecting tobacco. The study shows that, despite the low diversity of begomoviruses and betasatellites in Oman, the extant viruses/betasatellites are able to fill the niches that present themselves.


Plant Disease ◽  
2007 ◽  
Vol 91 (9) ◽  
pp. 1198-1198 ◽  
Author(s):  
Y. Shibuya ◽  
J. Sakata ◽  
N. Sukamto ◽  
T. Kon ◽  
P. Sharma ◽  
...  

Ageratum conyzoides L. plants affected with yellow vein disease were collected from Magelang, Bandung, and Purwokerto locations in Indonesia during 2001. A. conyzoides is a naturally occurring weed that is found in and around fields of cultivated pepper (Capsicum annuum L.) and tomato (Lycopersicon esculentum L.). It is frequently found with symptoms of yellow vein disease and the abundance of whiteflies on the affected plants suggested the possible involvement of a geminivirus. Total nucleic acids were extracted from nine samples collected from these locations of A. conyzoides-affected plants exhibiting yellow vein disease and amplified using PCR with geminivirus DNA-A-specific designed primers (virion-sense primer 5′-GAGCTCTTAGCCGCCTGAATGTTC-3′; complementary-sense primer 5′-GAGCTCGTCAGATGTTAAGACCTAC-3′) (1). A PCR-amplified product of approximately 2.7 kbp was obtained from each sample. Five independent sequences were cloned and sequenced from each sample. Sequence analysis showed that five of nine samples were Ageratum yellow vein virus (one each from Bandung and Purwokerto and three from Magelang) and the remaining four samples (two samples each from Bandung and Purwokerto) were a strain of Pepper yellow leaf curl Indonesia virus (PepYLCIDV). Full-length DNA-A of PepYLCIDV from systemic A. coniziodes was amplified using PCR with additional primers designed at only one restriction site (BamHI) (5′-GGATCCGCTTGTTCATCCTTTTCCAG-3′/5′-GGATCCCACATCTTTGGTTAGTGGAGGGTG-3′) and cloned. Three independent clones obtained were sequenced and analyzed. The sequence of a full-length DNA-A component was determined (2,760 bases, GenBank Accession No. AB267838). PCR using degenerate primers (DNABLC1: 5′-GTVAATGGRGTDCACTTCTG-3′; DNABLC2: 5′-RGTDCACTTCTGYARGATGC-3′, DNABLV2: 5′-GAGTAGTAGTGBAKGTTGCA-3′) of begomovirus DNA-B component (2), five independent clones were obtained and sequenced. Primers designed to amplify a full-length B component were constructed around a unique restriction site (BamHI) (5′-GGATCCCCTCATTCCTTTTGCGGAG-3′/5′-GGATCCACAGAGGAAAACTCGCAAGGC-3′). A PCR product was obtained from A. conyzoides samples and three independent clones were sequenced and analyzed. A full-length sequence of a begomovirus B component was determined (2,746 bases, GenBank Accession No. AB267839). Five open reading frames (ORF) were found in DNA-A and two in DNA-B. The DNA-A and DNA-B had a common region (CR) (74% nucleotide sequence identity) that comprised approximately 160 nucleotides. The DNA-A and DNA-B had an identical 31-base stem loop region in the CR. In addition, DNA-A and DNA-B had the highest nucleotide sequence identity (93%) with those of PepYLCIDV (GenBank Accession Nos. AB267834 and AB267835), suggesting it is a strain of PepYLCIDV, which is widely prevalent in Indonesia. To our knowledge, this is the first report of PepYLCIDV isolated from A. conyzoides plants affected with yellow vein disease. References: (1) R. W. Briddon and P. G. Markham. Mol. Biotechnol. 1:202, 1994. (2) S. K. Green et al. Plant Dis. 85:1286, 2001.


Author(s):  
E.O. Shmelkova ◽  
M.A. Slugina ◽  
A.A. Meleshin ◽  
E.V. Romanova

Работа посвящена разработке и тестированию универсальных праймеров для ПЦР-амплификации полноразмерных генов-ортологов β-фруктофуранозидазы (кислой вакуолярной инвертазы) у видов и сортов картофеля (Solanum tuberosum). Крахмал – основной источник энергии и резервный углевод, накапливающийся в амилопластах клубней. Образовавшаяся в результате фотосинтеза молекула глюкозы при реакции с фруктозой образует сахарозу – основную транспортную форму углеводов в растении. В клубни сахароза доставляется по флоэме (апопластный путь), где в межклеточном пространстве расщепляется до глюкозы и фруктозы, которые затем проникают в клетки паренхимы. Глюкоза служит в дальнейшем субстратом для синтеза крахмала в амилопластах. Однако при воздействии пониженных температур крахмал в клубнях картофеля разрушается до редуцирующих сахаров. Параллельно этому процессу идет ресинтез сахарозы до глюкозы и фруктозы за счет фермента кислой вакуолярной инвертазы (β-фруктофуранозидазы), кодируемой геном Pain-1. В совокупности эти процессы приводят к избыточному накоплению моносахаров в клубнях картофеля, так называемому холодовому осахариванию (cold-induced sweetening). При этом создаются условия для интенсивного образования меланоидинов, вызывающих потемнение мякоти картофеля, что значительно ухудшает товарное качество продукта. Таким образом, изучение гена Pain-1, кодирующего вакуолярную инвертазу, а именно, его идентификация и анализ структуры – важная задача, необходимая для поиска доноров, устойчивых к холодовому осахариванию. Первоочередная задача для этого – разработка и тестирование праймерных комбинаций, позволяющих амплифицировать полноразмерный ген у диких видов картофеля, а также сортов и линий культивируемого картофеля (S. tuberosum). В данной работе приведены результаты разработки и тестирования универсальных праймеров, с помощью которых можно амплифицировать как полноразмерные гены-ортологи, так и фрагменты гена Pain-1, а также подобраны оптимальные условия для проведения ПЦР реакции. Было разработано 6 праймерных комбинаций (PainF – PainR, PainF – Pain1exR, Pain1exF – Pain3exR, Pain2inF – Pain2inR, Pain3exF – Pain5exR, Pain5exF – PainR), среди которых комбинация PainF – PainR позволяла амплифицировать полноразмерный ген, остальные – внутренние и будут использованы в дальнейшем при секвенировании фрагментов исследуемого гена. Эти праймеры были успешно протестированы на 15 образцах, включающих представителей пяти дикорастущих видов картофеля (S. gourlay, S. chacoense, S. pinnatissectum, S. stoloniferum, S. vernei) и десяти сортов российской и зарубежной селекции (Гала, Ласунок, Ред Скарлетт, Рассет Бербанк, Мирас, Башкирский, Жуковский ранний, Матушка, Елизавета, Сударыня).The purpose of research is design and testing of universal primers for PCR amplification of full-length-fructofuranozidase orthologs genes (acid vacuolar invertase) in wild species and potato (Solanum tuberosum) varieties. Starch is the main source of energy and a reserve carbohydrate, that accumulates in tubers amyloplasts. Glucose molecule, produced by photosynthesis, reacts with fructose and forms sucrose, which is the main transport type of carbohydrates in the plant. In the tuber, sucrose is delivered via phloem (apoplast), where it splits into glucose and fructose, which then go to the parenchyma cells. Glucose is a further substrate for the starch synthesis in amyloplasts. However, low temperatures influence on potato tubers leads to starch break down to reducing sugars. In parallel to this process there is happens resynthesis of sucrose to glucose and fructose by acid vacuolar invertase enzyme (β-fructofuranosidase) encoded by Pain-1 gene. Together, these processes lead to an excessive accumulation of monosaccharides in potato tubers. This process also called as cold-induced sweetening. It creates conditions for the intensive formation of melanoidins, which cause a potato tubers darkening, which considerably impairs the commercial quality of the product. Thus, the study Pain-1 gene that encodes the vacuolar invertase (its identification and structure analysis) is an important task required for the search of donors resistant to cold-induced sweetening. The primary task for this is the design and testing of primer combinations that allow to amplify the full-length gene in wild potato species, varieties and lines of cultivated potato. In this work, we develop and test universal primers, that can amplify both full-length orthologs and fragments of the Pain-1 gene, and also select the optimal conditions for carrying out the PCR reaction. Summary. The purpose of research is design and testing of universal primers for PCR amplification of full-length-fructofuranozidase orthologs genes (acid vacuolar invertase) in wild species and potato (Solanum tuberosum) varieties. Starch is the main source of energy and a reserve carbohydrate, that accumulates in tubers amyloplasts. Glucose molecule, produced by photosynthesis, reacts with fructose and forms sucrose, which is the main transport type of carbohydrates in the plant. In the tuber, sucrose is delivered via phloem (apoplast), where it splits into glucose and fructose, which then go to the parenchyma cells. Glucose is a further substrate for the starch synthesis in amyloplasts. However, low temperatures influence on potato tubers leads to starch break down to reducing sugars. In parallel to this process there is happens resynthesis of sucrose to glucose and fructose by acid vacuolar invertase enzyme (β-fructofuranosidase) encoded by Pain-1 gene. Together, these processes lead to an excessive accumulation of monosaccharides in potato tubers. This process also called as cold-induced sweetening. It creates conditions for the intensive formation of melanoidins, which cause a potato tubers darkening, which considerably impairs the commercial quality of the product. Thus, the study Pain-1 gene that encodes the vacuolar invertase (its identification and structure analysis) is an important task required for the search of donors resistant to cold-induced sweetening. The primary task for this is the design and testing of primer combinations that allow to amplify the full-length gene in wild potato species, varieties and lines of cultivated potato. In this work, we develop and test universal primers, that can amplify both full-length orthologs and fragments of the Pain-1 gene, and also select the optimal conditions for carrying out the PCR reaction. In total 6 primer combinations were designed (PainF - PainR, PainF - Pain1exR, Pain1exF - Pain3exR, Pain2inF - Pain2inR, Pain3exF - Pain5exR, Pain5exF - PainR), where PainF - PainR primer combination allowed to amplify a full-sized gene, the rest are internal and will be used in the further fragments sequencing of the β-fructofuranosidase gene. These primers were successfully tested on 15 samples, including five wild species of potato (S. gourlay, S. chacoense, S. pinnatissectum, S. stoloniferum, S. vernei) and ten varieties of Russian and foreign breeding (Gala, Lasunok, Red Scarlet , Rasset Burbank, Miras, Bashkirsky, Zhukovsky ranniy, Matushka, Elizaveta, Sudaryna).


Plant Disease ◽  
2010 ◽  
Vol 94 (7) ◽  
pp. 924-924 ◽  
Author(s):  
C. Hernandez-Zepeda ◽  
T. Isakeit ◽  
A. Scott ◽  
J. K. Brown

During the okra growing season from August to November of 2009, symptoms reminiscent of geminivirus infection were observed on 75% of ‘Green Emerald’ Abelmoschus esculentus (L.) Moench, plants in a 0.2-km2 field in Hidalgo County, TX. Visible symptoms consisted of irregular yellow patches on leaves, distinctive yellow borders on leaf edges, and chlorosis of subsequently developing leaves. The whitefly vector of begomoviruses, Bemisia tabaci (Genn.), infested okra plants in the early growth stages during late July 2009. Total DNA was isolated from the leaves of three symptomatic okra plant samples (1) and used as the PCR template to amplify a 575-bp fragment of the coat protein gene (CP) using the universal begomovirus primers AV494 and AC1048 (2). PCR products of the expected size were cloned into the pGEM-T Easy (Promega, Madison, WI) and sequenced using the universal M13F and M13 R primers. ClustalV alignment indicated 99 to 100% shared nucleotide (nt) identity, and BLAST analysis revealed that the closest relative was Okra yellow mosaic Mexico virus - Tetekalitla (OkYMMV) (GenBank Accession No. EF591631) at 98%. To amplify the full-length DNA-A and a possible cognate DNA-B component, one plant that was positive by CP-PCR and DNA sequencing was selected for further analysis. Total DNA from this plant was used as template for a second detection method that consisted of rolling circle amplification (RCA) using the TempliPhi 100 Amplification System (GE Healthcare). RCA is a non-sequence-specific approach that permits amplification of circular DNA. The RCA products were linearized to release unit length ~2.6 kb DNA-A and DNA-B components using BamHI, and EcoRI, respectively. These products were cloned into pGEM3zf+ (Promega) and sequenced using M13F and M13 R primers and then by primer walking (>300 base overlap). Full-length DNA-A and DNA-B components were obtained, respectively, at 2,613 bp (GenBank Accession No. HM035059) and 2,594 bp (GenBank Accession No HM035060). Alignment of the DNA-A component using ClustalV (MegAlign, DNASTAR, Madison, WI) with begomoviral sequences available in GenBank indicated that it was 99% identical to OkYMMV DNA-A (GenBank Accession No. DQ022611). The closest relative to the DNA-B component (ClustalV) was Sida golden mosaic virus (SiGMV) (GenBank Accession No. AJ250731) at 73%. The nt identity of the 172-nt ‘common region’ present in the DNA-A and DNA-B components was 99%, and the iterons (predicted Rep binding motif) were identical for the two components, indicating that they are a cognate pair. The genome organization was typical of other New World bipartite begomoviruses. The economic losses due to infection by this virus could not be determined because an early freeze killed the plants. Hidalgo County is adjacent to Tamaulipas, Mexico, where ~50 km2 of okra are grown and the whitefly vector is also present. The identification of OkYMMV based on two independent detection methods, and the presence of begomovirus-like symptoms together with the whitefly vector, provide robust evidence for the association of OkYMMV-TX with diseased okra plants. To our knowledge, this is the first report of OkYMMV-TX infecting okra crops in Texas and in the continental United States. References: (1) J. J. Doyle and J. L. Doyle. Focus 12:13, 1990. (2) S. Wyatt and J. K. Brown. Phytopathology 86:1288, 1996.


Plant Disease ◽  
2013 ◽  
Vol 97 (10) ◽  
pp. 1352-1357 ◽  
Author(s):  
Bindu Poudel ◽  
William M. Wintermantel ◽  
Arturo A. Cortez ◽  
Thien Ho ◽  
Archana Khadgi ◽  
...  

Blackberry yellow vein disease is one of the most important diseases of blackberry in the United States. Several viruses are found associated with the symptomology but Blackberry yellow vein associated virus (BYVaV) appears to be the most prevalent of all, leading to the need for a better understanding of its epidemiology. Efficient detection protocols were developed using end-point and quantitative reverse-transcription polymerase chain reaction. A multi-state survey was performed on wild and cultivated blackberry to assess the geographical distribution of the virus. Two whitefly species, Trialeurodes abutilonea and T. vaporariorum, were identified as vectors and 25 plant species were tested as potential BYVaV hosts. The information obtained in this study can be used at multiple levels to better understand and control blackberry yellow vein disease.


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