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1.
ABSTRACT We demonstrated that only 11 isolates were associated with DNAbeta among 39 Tobacco curly shoot virus (TbCSV)-infected, field-collected samples. An infectious clone of TbCSV-[Y35], an isolate associated with DNAbeta, induced severe upward leaf curling in Nicotiana benthamiana. In the presence of its cognate DNAbeta (TbCSV-[Y35] DNAbeta), the symptom changed to a downward leaf curl. Furthermore, TbCSV-[Y35] alone was able to induce severe symptoms in tobacco and tomato plants, although co-infection with DNAbeta intensified symptom severity in tobacco plants. In contrast to other begomovirus-DNAbeta complexes, the satellite had no effect on the accumulation of TbCSV-[Y35] DNA in systemically infected host plants. The betaC1 mutant caused symptoms comparable to those induced by TbCSV-[Y35] in the absence of DNAbeta. TbCSV-[Y35] can be transmitted between plants by a whitefly vector, regardless of the presence or absence of DNAbeta. For a TbCSV isolate not associated with DNAbeta (TbCSV-[Y1]), systemic infection of N. benthamiana induced symptoms resembling those of TbCSV-[Y35]. Co-infection of TbCSV-[Y1] with TbCSV-[Y35] DNAbeta induced symptoms similar to those following infection by TbCSV-[Y35] and its DNAbeta. This indicates that TbCSV DNAbeta is not necessary for infection but intensifies symptoms in a host-dependent manner. Thus, TbCSV may represent an evolutionary intermediate between the DNAbeta requiring begomoviruses and the truly monopartite begomoviruses. The relevance of these results to our present understanding of the evolution of begomovirus-satellite disease complexes is discussed. 相似文献
2.
ABSTRACT Ageratum conyzoides plants exhibiting yellow vein symptoms, collected near Haikou, Hainan Province, China, contained begomoviral DNA-A-like molecules. The complete sequences of the molecules from two samples, Hn2 and Hn2-19, were shown to consist of 2,768 and 2,748 nucelotides (nt), respectively. These sequences have more than 97% nucleotide sequence identity, but less than 86% identity with other reported begomovirus sequences. In line with the taxonomic convention for begomoviruses, Hn2 and Hn2-19 are therefore considered to represent isolates of a distinct begomovirus species, for which the name Ageratum yellow vein China virus (AYVCNV) is proposed. Sequence alignment shows AYVCNV has arisen by recombination among viruses related to Ageratum yellow vein virus, Papaya leaf curl China virus, and an unidentified begomovirus. Southern blot analyses revealed that all plants sampled contained molecules resembling DNAbeta. DNAbeta molecules from three samples were 1,323 or 1,324 nt long and had >98% sequence identity but <81% identity with previously reported DNAbeta sequences. Infectious clones of Hn2 and its associated DNAbeta were constructed and agroinoculated to plants. Hn2 alone caused sporadic asymptomatic systemic infection of Nicotiana benthamiana, N. glutinosa, Lycopersicon esculentum, Petunia hybrida, and A. conyzoides but its accumulation was much enhanced in plants co-inoculated with DNAbeta. The co-inoculated N. benthamiana, N. glutinosa, P. hybrida, and L. esculentum plants developed leaf curling or leaf crinkling symptom; those in A. conyzoides were typical of ageratum yellow vein disease. When the DNAbeta molecules associated with four other Chinese begomoviruses were coinoculated with Hn2 to N. benthamiana and N. glutinosa, the DNAbeta molecules were replicated, and the plants developed systemic symptoms of types that were specific for each DNAbeta. This illustrates that there is less specific interaction between monopartite begomovirus and DNAbeta than between the DNA-A and DNA-B of begomoviruses with bipartite genomes. 相似文献
3.
ABSTRACT The molecular diversity of Tomato leaf curl viruses (ToLCVs), from the two main tomato growing areas of Jessore and Joydebpur, Bangladesh, was investigated. The viral DNA was amplified from tomato plants exhibiting mild and severe symptoms by polymerase chain reaction, and the complete genomes of the ToLCVs were sequenced. An isolate of the bipartite Tomato leaf curl New Delhi virus-Severe (ToLCNDV-Svr) was associated with the severe symptom phenotype from Jessore (ToLCNDV-Svr[Jes]). A previously undescribed monopartite virus, designated Tomato leaf curl Joydebpur virus-Mild (ToLCJV-Mld), was sequenced from plants showing mild symptoms. ToLCNDV-Svr[Jes] was most closely related to ToLCNDV-[Lucknow] at 95.7% nucleotide (nt) identity and Tomato leaf curl Gujarat virus-[Varanasi] at 90.6% nt identity, based on DNA-A and -B component sequences. ToLCJV-Mld was similar to Pepper leaf curl Bangladesh virus at 87.1% DNA-A nt identity. Identification of ToLCNDV-Svr[Jes] and ToLCJV-Mld was in addition to the previously described Tomato leaf curl Bangladesh virus, with which they shared 73.2 and 86.0% DNA-A nt identities, thus demonstrating the existence of at least three distinct viruses infecting tomato in Bangladesh. Nucleotide identities and placement in phylogenetic trees suggested that the three ToLCVs may have had different evolutionary pathways. The whitefly, Bemisia tabaci, transmitted the viruses of this study equally efficiently. Four tomato cultivars (TLB111, TLB130, TLB133, and TLB182) resistant/ tolerant to South Indian ToLCV were screened against the Bangladesh ToLCVs in 2003-04. Although challenged by diverse viruses and potentially mixed infections, disease incidence remained low (6 to 45%) in the resistant cultivars compared with local cultivars (68 to 100%). 相似文献
4.
ABSTRACT The biological and molecular properties of Tomato leaf curl Gujarat virus from Varanasi, India (ToLCGV-[Var]) were characterized. ToLCGV-[Var] could be transmitted by grafting and through whitefly transmission in a persistent manner. The full-length genome of DNA-A and DNA-B of ToLCGV-[Var] was cloned in pUC18. Sequence analysis revealed that DNA-A (AY190290) is 2,757 bp and DNA-B (AY190291) is 2,688 bp in length. ToLCGV-[Var] could infect and cause symptoms in tomato, pepper, Nicotiana benthamiana, and N. tabacum when partial tandem dimeric constructs of DNA-A and DNA-B were co-inoculated by particle bombardment. DNA-A alone also is infectious, but symptoms were milder and took longer to develop. ToLCGV-Var virus can be transmitted through sap inoculation from infected tomato plants to the above-mentioned hosts causing the same symptoms. Open reading frames (ORFs) in both DNA-A and DNA-B are organized similarly to those in other begomoviruses. DNA-A and DNA-B share a common region of 155 bp with only 60% sequence identity. DNA-B of ToLCGV-[Var] shares overall 80% identity with DNA-B of Tomato leaf curl New Delhi virus-Severe (ToLCNDV-Svr) and 75% with ToLCNDV-[Lucknow] (ToLCNDV-[Luc]). Comparison of DNA-A sequence with different begomoviruses indicates that ToLCGV-[Var] shares 84% identity with Tomato leaf curl Karnataka virus (ToLCKV) and 66% with ToLCNDV-Svr. ToLCGV-[Var] shares a maximum of 98% identity with another isolate of the same region (ToLCGV-[Mir]; AF449999) and 97% identity with one isolate from Gujarat (ToLCGV-[Vad]; AF413671). All three viruses belong to the same species that is distinct from all the other geminivirus species described so far in the genus Begomovirus of the family Geminiviridae. The name Tomato leaf curl Gujarat virus is proposed because the first sequence was taken from an isolate of Gujarat, India. 相似文献
5.
Youping Xu Xinzhong Cai Xueping Zhou 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(3):287-294
Three begomovirus isolates were obtained from tomato plants showing leaf curl symptoms in Guangxi province of China. Typical
begomovirus DNA components representing the three isolates (GX-1, GX-2 and GX-3) were cloned and their full-length sequences
were determined to be 2752 nucleotides. Nucleotide identities among the three viral sequences were 98.9–99.7%, but all shared
<86.7% nucleotide sequence identity with other reported begomoviruses. The sequence data indicated that GX-1, GX-2 and GX-3
are isolates of a distinct begomovirus species for which the name Tomato leaf curl Guangxi virus (ToLCGXV) is proposed. Further
analysis indicated that ToLCGXV probably originated through recombination among viruses related to Ageratum yellow vein virus,
Tomato leaf curl China virus and Euphorbia leaf curl virus. PCR and Southern blot analyses demonstrated that isolates GX-1
and GX-2 were associated with DNAβ components, but not isolate GX-3. Sequence comparisons revealed that GX-1 and GX-2 DNAβ
components shared the highest sequence identity (86.2%) with that of Tomato yellow leaf curl China virus (TYLCCNV). An infectious
construct of ToLCGXV isolate GX-1 (ToLCGXV-GX) was produced and determined to be highly infectious in Nicotiana benthamiana, N. glutinosa, tobacco cvs. Samsun and Xanthi, tomato and Petunia hybrida plants inducing leaf curl and stunting symptoms. Co-inoculation of tomato plants with ToLCGXV-GX and TYLCCNV DNAβ resulted
in disease symptoms similar to that caused by ToLCGXV-GX alone or that observed in infected field tomato plants. 相似文献
6.
R. W. Briddon 《EPPO Bulletin》2002,32(1):1-5
The diversity of whitefly‐transmitted begomoviruses in Europe is low, most being exotic, introduced species. The only agriculturally important viruses are two species causing tomato yellow leaf curl. These viruses are believed to have originated in the Middle East but have since spread right across the Mediterranean region. Two ornamentals (Abutilon and Lonicera japonica) were introduced into Europe from the New World and the Far East, respectively, for the striking symptoms induced by the viruses which infect them. The virus infecting honeysuckle (Honeysuckle yellow vein mosaic virus) has been shown to be part of newly identified cluster of begomoviruses which require an additional component, a satellite molecule termed DNA β, to induce symptoms in their host plants. A further begomovirus, Ipomoea yellow vein virus, which infects the weed Ipomoea indica, is present in the Mediterranean region. The precise origin and relationship of this virus to other begomoviruses is unclear. 相似文献
7.
A. Ouattara F. Tiendrébéogo P. Lefeuvre M. Hoareau S. Claverie A. Allibert F. Chiroleu E.V. Traoré N. Barro O. Traoré J.-M. Lett 《Plant pathology》2020,69(2):379-392
In West and Central Africa, as in many regions of the world, vegetables are severely affected by geminivirus diseases. In Burkina Faso, observation of various virus-like symptoms, especially on tomato, suggests the involvement of several geminiviruses and underlines the pressing need for additional information on their diversity, distribution, prevalence and host plant reservoirs. Large-scale surveys conducted in Burkina Faso confirmed the presence of tomato (yellow) leaf curl diseases (ToLCD-TYLCD) and geminiviruses in all localities with mean prevalences of 25% and 45%, respectively. Five geminiviruses including four begomoviruses (pepper yellow vein Mali virus (PepYVMLV), tomato leaf curl Burkina Faso virus, tomato leaf curl Mali virus and tomato leaf curl Ghana virus) and a dicot-infecting mastrevirus (chickpea chlorotic dwarf virus) were characterized on tomato. In addition, PepYVMLV and cotton leaf curl Gezira virus (CLCuGeV) were characterized on pepper and okra, respectively, in combination or not with alphasatellites and betasatellites for CLCuGeV. The most severe, prevalent and widely distributed virus on vegetables was PepYVMLV, which was characterized for the first time in combination with a genetically divergent DNA-B component that may constitute a key factor of PepYVMLV pathogenicity. Of the eight weeds identified as potential reservoir hosts of begomoviruses, four host PepYVMLV. The results confirm the importance of geminivirus diseases on vegetable crops in Burkina Faso and highlight the complex association of geminiviruses and satellites. The detection of begomoviruses in weeds growing close to crops points to the increasing necessity to consider reservoir plants and virus communities in the control of virus diseases. 相似文献
8.
In this study, Tomato yellow leaf curl Sardinia virus (TYLCSV) and the strains Israel and Mild of Tomato yellow leaf curl virus (TYLCV-IL, TYLCV-Mld) were detected for the first time in four cucurbit crops in Jordan by nested polymerase chain reaction (nPCR). These viruses cause the tomato yellow leaf curl disease (TYLCD) in tomato. Cucumber, squash, melon and watermelon plants inoculated with TYLCV-IL[JO:Cuc], TYLCV-Mld, TYLCSV-IT[IT:Sar:88] and the Jordanian isolate of TYLCV (TYLCV-JV) did not show disease symptoms. However, virus-specific fragments were detected in uppermost leaves of symptomless plants by nPCR. A whitefly transmission test showed that Bemisia tabaci could transmit TYLCV-Mld from cucumber into tomato and jimsonweed plants. However, all infected tomato plants remained symptomless. In addition, results of semi-quantitative PCR (sqPCR) analysis showed that the relative amount of TYLCV-Mld DNA acquired by B. tabaci from cucumber plants was less than that acquired from tomato plants. 相似文献
9.
南疆温室番茄黄化曲叶病病毒种类的分子鉴定 总被引：1，自引：1，他引：0
为明确南疆温室番茄黄化曲叶病的病毒种类,利用双生病毒的兼并引物通过PCR扩增,对采集的20个番茄病株进行了分子检测.从20个病株中均扩增到约500 bp的目标片段,对其中4株进行克隆和测序,其相互间序列同源性为97.1％ ～99.3％,与番茄黄化曲叶病毒(Tomato yellow leaf curl virus,TYLCV)的同源性较高,为98.6％ ～ 99.5％.随机选取莎车分离物KS2-5进行全基因组的克隆和测序,KS2-5 DNA全长为2781 nt(序列号:JQ807735),具有典型的双生病毒基因组特征,与TYLCV其它分离物同源性达到98.9％～99.5％,而与其它粉虱传双生病毒的序列同源性较低,为68.3％ ～75.5％,表明危害南疆温室番茄的病毒种类为番茄黄化曲叶病毒TYLCV. 相似文献
10.
Genetic diversity and mixed infections of begomoviruses infecting tomato, pepper and cucurbit crops in Nicaragua 总被引：1，自引：0，他引：1
M. Ala-Poikela E. Svensson ‡ A. Rojas T. Horko L. Paulin J. P. T. Valkonen A. Kvarnheden † 《Plant pathology》2005,54(4):448-459
Begomoviruses were detected in Nicaraguan fields of tomato ( Lycopersicon esculentum ) and adjacently growing plants of pepper ( Capsicum annuum ), chilli pepper ( C . baccatum ), cushaw ( Cucurbita argyrosperma ) and Mexican fireplant ( Euphorbia heterophylla ) using polymerase chain reaction (PCR) and universal begomovirus primers. All tomato and Mexican fireplant plants showing symptoms were infected with begomoviruses, while only 30–46% of the pepper, chilli pepper and cushaw plants showing symptoms tested virus-positive. No begomoviruses were found in potato. The virus species were provisionally identified by sequencing 533 bp of the viral coat protein gene ( AV1 ). Tomato severe leaf curl virus (ToSLCV), Tomato leaf curl Sinaloa virus (ToLCSinV) and Pepper golden mosaic virus (PepGMV) were found to infect both tomato and pepper. A new provisional species designated Tomato leaf curl Las Playitas virus (ToLCLPV) was detected in a tomato plant. Squash yellow mottle virus (SYMoV) and PepGMV were found in cucurbits, the latter for the first time in this host. Euphorbia mosaic virus (EuMV) was detected in Mexican fireplant. Sequencing of a larger number of PCR-amplified clones from selected plants revealed intraspecific viral sequence variability, and also multiple begomovirus infections which could represent up to three species in a single tomato or cushaw plant. Phylogenetic grouping of virus sequences did not correlate with the host of origin. 相似文献
11.
由粉虱传双生病毒引起的番茄曲叶病［1］在我国最初仅分布在海南、云南、广东和广西,自2006年上海市和浙江省先后在番茄上发现番茄黄化曲叶病毒（Tomato yellow leaf curl virus,TYLCV）以来,该病害蔓延迅速,在多个省份的番茄上暴发成灾［2］。引起番茄曲叶病害的病原较复杂,在我国其主要病原为TYLCV、中国番木瓜曲叶病毒（Papaya leaf curl China virus, PaLCuCNV）、中国番茄黄化曲叶病毒(Tomato yellow leaf curl China virus, TYLCCNV)、泰国番茄黄化曲叶病毒（Tomato yellow leaf curl Thailand virus, TYLCTHV）和台湾番茄曲叶病毒（Tomato leaf curl Taiwan virus, ToLCTWV）［2~5］,而浙江省的主要病原为TYLCV和ToLCTWV。选育抗病品种是防治番茄黄化曲叶病最有效的手段。了解番茄品种对不同双生病毒的抗性,对因地制宜布局抗病品种具有重要意义。浙杂502、浙粉701、浙粉702是浙江省大规模种植的番茄品种,为了解这些品种对上述5种病毒的抗性,本研究利用5种病毒的侵染性克隆,在人工接种条件下,综合评定分析这3个番茄品种的抗病指标。 相似文献
12.
Ho-Hsiung Chang Hsin-Mei Ku Wen-Shi Tsai Rui-Che Chien Fuh-Jyh Jan 《European journal of plant pathology / European Foundation for Plant Pathology》2010,127(2):219-228
Oriental melon plants, Cucumis melo var. makuwa cv. Silver Light, showing virus-induced symptoms of mosaic, leaf curl and puckering were observed in the fields of eastern
Taiwan in 2007. A virus culture, designated as SL-1, isolated from the diseased melon was established in systemic host plants,
Nicotiana benthamiana and oriental melon, by mechanical inoculation. SL-1 did not react to the antisera against common cucurbit-infecting RNA viruses.
Viral DNAs extracted from the diseased plant were amplified with the degenerate primers for begomoviruses. The full-length
genomic DNA-A and DNA-B of SL-1 were sequenced and found to be closest, with 97.7% and 90.6% nucleotide identity, respectively,
to Tomato leaf curl New Delhi begomovirus (ToLCNDV) cucumber isolate from a group of cucurbit-infecting begomoviruses. The virus SL-1 was designated as ToLCNDV oriental
melon isolate (ToLCNDV-OM). The pathogenicity of ToLCNDV-OM was confirmed by agroinfection. Progeny virus from the agroinfected
N. benthamiana plants was able to infect oriental melon by mechanical inoculation and caused symptoms similar to the original diseased melon
in the field. The ToLCNDV-OM also infected five other species of cucurbitaceous plants by mechanical inoculation. This is
the first report of a new ToLCNDV isolate causing severe disease on oriental melon in Taiwan. 相似文献
13.
Morilla G Janssen D García-Andrés S Moriones E Cuadrado IM Bejarano ER 《Phytopathology》2005,95(9):1089-1097
ABSTRACT Tomato yellow leaf curl (TYLC) is one of the most devastating pathogens affecting tomato (Lycopersicon esculentum) worldwide. The disease is caused by a complex of begomovirus species, two of which, Tomato yellow leaf curl Sardinia virus (TYLCSV) and Tomato yellow leaf curl virus (TYLCV), are responsible for epidemics in Southern Spain. TYLCV also has been reported to cause severe damage to common bean (Phaseolus vulgaris) crops. Pepper (Capsicum annuum) plants collected from commercial crops were found to be infected by isolates of two TYLCV strains: TYLCV-Mld[ES01/99], an isolate of the mild strain similar to other TYLCVs isolated from tomato crops in Spain, and TYLCV-[Alm], an isolate of the more virulent TYLCV type strain, not previously reported in the Iberian Peninsula. In this work, pepper, Nicotiana benthamiana, common bean, and tomato were tested for susceptibility to TYLCV-Mld[ES01/99]and TYLCV-[Alm] by Agrobacterium tumefaciens infiltration, biolistic bombardment, or Bemisia tabaci inoculation. Results indicate that both strains are able to infect plants of these species, including pepper. This is the first time that infection of pepper plants with TYLCV clones has been shown. Implications of pepper infection for the epidemiology of TYLCV are discussed. 相似文献
14.
ABSTRACT The genome of Tomato leaf curl virus (ToLCV) from Bangalore, India, a whitefly-transmitted geminivirus, was cloned (pIND9) and sequenced. The circular DNA of 2,759 nucleotides (U38239) is organized similarly to that of other begomoviruses with monopartite genomes. Comparison of the nucleotide sequence of pIND9 with other tomato-associated begomoviruses from India (Tomato leaf curl Bangalore virus [ToLCBV, Z48182]) and Tomato leaf curl New Delhi virus-Severe (ToLCNdV-Svr, U15015) showed moderate DNA sequence identities (82 to 87%) between capsid protein (CP) genes but low identities (66 to 67%) for the intergenic regions and the replication-associated protein (Rep) genes (75 to 81% identity). Phylogenetic trees generated with nucleotide sequences of the Rep and CP genes of 26 begomoviruses indicated that this ToLCV is distinct from other begomoviruses and that it may be a recombinant virus derived from at least three different viral lineages. Tomatoes (Lycopersicon esculentum) inoculated with the cloned DNA monomer of ToLCV (pIND9) via particle bombardment developed leaf curling and yellowing symptoms. The virus was transmitted by Bemisia tabaci biotype B from tomatoes infected via particle bombardment to healthy tomatoes and by sap inoculation from infected tomatoes to tomato, Nicotiana benthamiana and N. tabacum. This ToLCV is a distinct member of the genus Begomovirus from India that differs from the previously characterized Tomato leaf curl Sadasivanagar virus isolate Bangalore 1 (L12739), ToLCBV (Z48182), ToLCBV isolate Bangalore 4 (AF165098), and the bipartite ToLCNdV (U15015, U15016). Thus, this ToLCV is named Tomato leaf curl Karnataka virus (ToLCKV). 相似文献
15.
A. A. M. Al‐Shihi A. J. Khan S. Akhtar A. T. M. Lima F. M. Zerbini R. W. Briddon 《Plant pathology》2014,63(5):1177-1184
Whitefly‐transmitted begomoviruses are the most important limiting factor for tomato cultivation in Oman, particularly in the Al‐Batinah region, the major agricultural area of the country. Commercial farms in the Al‐Batinah region were surveyed during January–March 2013. Samples of tomato showing leaf curl disease symptoms typical of begomoviruses were collected and analysed. Full‐length sequences of five clones were shown to have relatively low percentage identity values to known begomoviruses, with the highest (88·6%) to isolates of Tomato leaf curl Oman virus (ToLCOMV), a begomovirus previously reported in Oman, indicating that these represent a newly identified species, for which the name Tomato leaf curl Barka virus (ToLCBrV) is proposed. Four isolates of ToLCBrV were found associated with Tomato leaf curl betasatellite (ToLCB). The five isolates of ToLCBrV characterized in this study were shown to be recombinants, with ToLCOMV as the major parent, and a fragment of Croton yellow vein virus (CrYVV) spanning the 3′ half of the replication‐associated protein. The significance of these findings is discussed. 相似文献
16.
García-Cano E Resende RO Boiteux LS Giordano LB Fernández-Muñoz R Moriones E 《Phytopathology》2008,98(5):618-627
Tomato-infecting begomoviruses comprise a complex of monopartite and bipartite virus species that cause severe yield and quality losses worldwide. Therefore, the availability of wide spectrum resistance for begomovirus control is desirable. However, limited sources of resistance are available. In this study, three tomato inbred lines with resistance to bipartite begomoviruses of Brazil were tested for resistance to monopartite begomoviruses associated with the tomato yellow leaf curl disease (TYLCD). Stable resistance to Tomato yellow leaf curl virus was observed either by inoculation with Bemisia tabaci or with Agrobacterium tumefaciens using an infectious clone. The resistance resulted in a complete absence of TYLCD symptoms and restricted virus accumulation. Further studies performed with the line '468-1-1-12' indicated that the resistance was also effective against three other virus species associated with TYLCD, indicating wide spectrum resistance of this source. Quantitative genetics analyses suggested that a major recessive locus with epistatic interactions is controlling the resistance to TYLCD in '468-1-1-12', which could facilitate introgression of this trait into elite tomato lines. The resistance was stable under field conditions with high TYLCD pressure. Mild symptoms could be observed in these conditions, and recovery from disease and from virus infection suggested an active host antiviral defense mechanism. The differential reaction of '468-1-1-12' against a number of TYLCD-associated viruses and artificial chimeras between them allowed to identify a region of the virus genome that presumably contains a virus determinant for breaking the resistance to infection observed in '468-1-1-12'. 相似文献
17.
18.
A simple procedure to evaluate relative resistance and tolerance of tomato cultivars to the begomoviruses causing tomato yellow leaf curl (TYLC) disease in Spain was developed. To estimate the resistance and tolerance levels of a cultivar, several formulae were developed based on the ratio of infected plants, virus titre (estimated by tissue–print hybridization) and symptom intensity. The formulae were applied to five commercial tomato cultivars (Amoretto, Birloque, Royesta, Tovigreen and Ulises) naturally infected by TYLC viruses. The analyses showed that Ulises, Birloque and Tovigreen exhibited a moderate resistance, and Ulises was also highly tolerant. There was a positive correlation between symptom intensity and virus titre in infected plants, suggesting that the hybridization technique could also be used as an early estimator of tolerance. Finally, molecular hybridization and nucleotide sequence analyses of the begomovirus intergenic region showed that the local TYLC virus population consisted of a single species, Tomato yellow leaf curl virus (TYLCV, formerly TYLCV-Israel), with low genetic variation (nucleotide identity between isolates higher than 97%). 相似文献
19.
Molecular and biological characterization of the begomovirus isolate BR:LNS2:Pas:01, obtained from yellow passionfruit plants in Livramento de Nossa Senhora, Bahia state, Brazil, was carried out. Sequence analysis demonstrated that the BR:LNS2:Pas:01 DNA‐A had highest nucleotide sequence identity with Tomato chlorotic mottle virus (77%) and had five ORFs corresponding to the genes cp, rep, trap, ren and ac4. The DNA‐B had highest nucleotide sequence identity with Tomato yellow spot virus (74%) and two ORFs corresponding to the genes mp and nsp. These identity values indicate that this isolate represents a new begomovirus species, for which the name Passionfruit severe leaf distortion virus (PSLDV), is proposed. Phylogenetic analysis clustered the PSLDV DNA‐A and ‐B in a monophyletic branch with Brazilian tomato‐infecting begomoviruses. The isolate’s host range was restricted to species from the Passifloraceae and Solanaceae. PSLDV‐[BR:LNS2:Pas:01] was capable of forming pseudorecombinants with tomato‐infecting begomoviruses, reinforcing its close relationship with these viruses and suggesting a possible common origin. However, the virus was not capable of infecting tomato. 相似文献
20.
双生病毒是一类在全世界范围内广泛发生的单链环状DNA病毒。本文对从湖南采集到的6例(洋姜、番茄、萝卜、赛葵、甘薯、牵牛花)疑似双生病毒侵染的植物叶片进行了分子鉴定。利用滚环扩增技术(RCA)对样品DNA进行扩增,分别对其RCA产物进行酶切,并将酶切得到的片段测序后进行BLAST比对,结果显示番茄样品中的病毒分离物与番茄黄化曲叶病毒相似性最高(99%),牵牛花样品中的病毒分离物与甘薯卷叶病毒相似性最高(99%),证明这两个分离物是单组分DNA-A双生病毒。这是在湖南省首次发现并报道双生病毒的全核酸序列。 相似文献