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1.
A stock culture of cotton leaf curl virus from Pakistan (CLCuV-PK), was transmitted by whiteflies (Bemisia tabaci) to seven plant species, including French bean, okra, tobacco and tomato, and caused vein thickening and leaf curl symptoms. It was readily detected in triple antibody sandwich ELISA (TAS-ELIS A) by 11 out of 31 monoclonal antibodies raised against the particles of three other geminiviruses: African cassava mosaic, Indian cassava mosaic and okra leaf curl viruses. Reaction strength was enhanced when the tissue extraction fluid contained sodium sulphite. Minor variations in epitope profile were found among virus isolates from cotton (Gossypium hirsutum) collected from different districts in Pakistan over a 5-year period. These epitope profiles were distinguishable from that of cotton leaf curl virus from G. barbadense in southern India but indistinguishable from the profiles of viruses causing yellow vein disease of okra in India or Pakistan, or leaf curl of okra {Abelmoschus esculentus), Hibiscus tiliaceus, radish or sunflower in Pakistan, suggesting that these plants are putative natural hosts of CLCuV-PK. The viruses in cotton, and in okra with leaf curl or yellow vein symptoms, were also detected by PCR with three pairs of CLCuV-PK-specific primers. Five additional whitefly-transmitted geminiviruses were found among isolates from 11 other naturally-infected species in Pakistan, and were distinguished by their epitope profiles. These viruses were associated, respectively, with tobacco leaf curl, squash yellow blotch, tomato yellow leaf curl, watermelon leaf crinkle and soybean yellow mosaic diseases. The first four of these viruses were detected readily by PCR with geminivirus general primers but only weakly, if at all, with two pairs of CLCuV-PK-specific primers. Pakistani crops are infected with a range of distinguishable but relatively closely related whitefly-transmitted geminiviruses, some of which resemble those found in India.  相似文献   

2.
Eggplant (Solanum melongena L.) plants with severe leaf mosaic and mottling were found in a kitchen garden near cotton fields in Pakistan. Rolling Circle Amplification products from six of the naturally infected eggplant plants, subjected to PCR, successfully amplified expected products of 2.8 and 1.4 kb using begomovirus and betasatellite‐specific primers, respectively. Based on 99% nucleotide sequence identity, the virus was identified as a variant of Cotton leaf curl Burewala virus (CLCuBuV) (GenBank Accession No. HG428709). Likewise, the sequenced betasatellite with a maximum of 97% nucleotide sequence identity was recognized as a new variant of Cotton leaf curl Multan betasatellite (CLCuMuBMul) (GenBank Accession No. HG428708). The symptomatic induction of Cotton leaf curl disease in CLCuBuV susceptible cotton genotype CIM‐496 by back‐indexing further confirmed the presence of CLCuBuV in eggplant. This is the first report of CLCuBuV and its associate betasatellite in naturally infected plants of eggplant.  相似文献   

3.
A leaf curl disease with symptoms typical of begomoviruses was observed in bean (Phaseolus vulgaris) at the Main Research Farm of the Indian Institute of Pulses Research, Kanpur, India. Infected plants had severe distortion of leaves and the plants were unproductive. PCR indicated the involvement of French bean leaf curl virus (JQ866297), a recently described Begomovirus, and Tomato leaf curl Gujarat virus (ToLCGV). The full‐length genome of ToLCGV associated with leaf curl disease of bean was 2757 nucleotides long and had maximum identity (97–98%) with seven isolates of ToLCGV (AY234383, AF449999, EU573714, GQ994098, AY190290, FR819708, AF413671) and is designated as Tomato leaf curl Gujarat virus‐(IN:Knp:Bean:2013) (KF440686). To the best of our knowledge, this is the first record of ToLCGV infecting a leguminous host, P. vulgaris.  相似文献   

4.
Whitefly transmitted begomoviruses (family Geminiviridae) are the major reason for significant yield losses of dicotyledonous crops in tropics and subtropics. Okra (Abelmoschus esculentus) is one of the important vegetable crops, and leaf curl disease caused by geminiviruses is the most important limiting factor for its production in Pakistan. Here, we report a new species of okra‐infecting begomovirus in south‐eastern region of Pakistan and the name Okra enation leaf curl virus (OELCuV) complex is proposed. This okra enation leaf curl disease complex (OELCuD) in Pakistan is found to be associated with Ageratum conyzoides symptomless alphasatellite (AConSLA). All efforts to clone the betasatellite were unsuccessful. Comprehensive sequence analyses suggest that intermalvaceous recombination between okra and cotton‐infecting begomoviruses resulted in the evolution of the new species. Surprisingly, Bhendi yellow vein mosaic virus (BYVMV) which has not been reported previously from Pakistan is the major parent while Cotton leaf curl Multan virus (CLCuMV) acts as a distant parent of the virus. Comparative recombination analysis also reveals that okra‐infecting begomoviruses from south and north‐western India is causing OELCuD in the Pakistan by recombining with CLCuMV at the Rep (1964–1513 nts). Recombination is common among geminiviruses and recombining of BYVMV and CLCuMV resulted in a new species: OELCuV. To the best of our knowledge, this evolution of a new species of okra‐infecting begomovirus is the first report of intermalvaceous recombination where Rep acts as the target region.  相似文献   

5.
A whitefly-transmitted infectious agent, associated with geminate particles, induced distinct symptoms on several Ipomoea species, but not on I. batatas cv. Georgia Jet. The virus was transmitted by Bemisia argentifolii in a persistent manner and by grafting, but not mechanically. No transmission to species outside Ipomoea was obtained. Extracts from infected Ipomoea plants hybridised with a bean yellow mosaic virus riboprobe and a tomato yellow leaf curl virus riboprobe, although not so strongly as hybridisation of these riboprobes with extracts from plants infected with the homologous viruses. Based on host range, we consider this virus to be distinct from sweet potato leaf curl virus reported from the Far East, and propose it be named “Ipomoea crinkle leaf curl virus” (ICLCV).  相似文献   

6.
Kidney bean (Phaseolus vulgaris) plants exhibiting foliar yellow mosaic symptoms and some leaf crumpling were identified in the Al Batinah region of Oman. Rolling circle amplification and polymerase chain reaction identified a bipartite begomovirus (family Geminiviridae) and a betasatellite in association with the symptomatic plants. Analysis of full‐length sequences showed the virus to be Mungbean yellow mosaic Indian virus (MYMIV) and the betasatellite Tomato leaf curl betasatellite (ToLCB). This is the first identification of a legume‐adapted begomovirus in Oman and the first identification of MYMIV in association with the betasatellite ToLCB. The isolate of MYMIV from Oman shows the greatest levels of sequence identity to isolates occurring in South Asia and South‐East Asia, suggesting that the virus has only recently been introduced. The significance of these findings is discussed.  相似文献   

7.
Hibiscus leaf curl disease (HLCuD) occurs widely in India. Infected hibiscus plants show vein thickening, upward curling of leaves and enations on the abaxial leaf surface, reduction in leaf size and stunting. The commonly‐occurring weeds (Ageratum conyzoides, Croton bonplandianum and Euphorbia geniculata), Nicotiana benthamiana, Nicotiana glutinosa and Nicotiana tabacum (var. Samsun, Xanthi), cotton and tomato were shown to be susceptible to HLCuD. One of the four species of hibiscus (Hibiscus rosa‐sinensis) and 75 of the 101 commercial hybrids/varieties grown in the Bangalore area of southern India were also susceptible. Two virus isolates associated with HLCuD from Bangalore, South India (Ban), and Bhubaneswar, North India (Bhu), were detected serologically and by PCR‐mediated amplification of virus genomes. The isolates were characterised by sequencing a fragment of DNA‐A component (1288 nucleotides) and an associated satellite DNA molecule of 682 nucleotides. Phylogenetic analyses of these DNA‐A sequences clustered them with Old World cotton‐infecting begomoviruses and closest to Cotton leaf curl Multan virus (CLCuMV) at 95–97% DNA‐A nucleotide identities. The 682‐nucleotide satellite DNA molecules associated with the HLCuD samples Ban and Bhu shared 96.9% sequence identity with each other and maximum identity (93.1–93.9% over positions 158–682) with ~1350‐nucleotide DNA‐β satellite molecules associated with cotton leaf curl disease in Pakistan and India (accession nos AJ298903, AJ316038). HLCuD in India, therefore, appears to be associated with strains of CLCuMV, a cotton‐infecting begomovirus from Pakistan, which is transmitted in a persistent manner by Bemisia tabaci.  相似文献   

8.
An epidemic of chilli leaf curl disease was recorded in 2004 in Jodhpur, a major chilli‐growing area in Rajasthan, India. Several isolates were efficiently transmitted by the whitefly (Bemisia tabaci), all of which induced severe leaf curl symptoms in chilli. A single whitefly was capable of transmitting the virus, and eight or more whiteflies per plant resulted in 100% transmission. The minimum acquisition access period (AAP) and inoculation access period (IAP) were 180 and 60 min, respectively. The virus persisted in whiteflies for up to 5 days postacquisition. Of 25 species tested, the virus infected only five (Capsicum annuum, Carica papaya, Solanum lycopersicum, Nicotiana tabacum and N. benthamiana). The virus was identified as Chilli leaf curl virus (ChiLCV), which shared the closest sequence identity (96.1%) with an isolate of ChiLCV from potato in Pakistan and showed sequence diversity up to 12.3% among the ChiLCV isolates reported from India and Pakistan. A betasatellite was identified, which resembled most closely (97.3%) that of Tomato leaf curl Bangladesh betasatellite previously reported from chilli and tomato leaf curl in India. The betasatellite was very different from that reported from chilli leaf curl in Pakistan, indicating that different betasatellites are associated with chilli leaf curl in India and Pakistan. We describe here for the first time the virus–vector relationships and host range of ChiLCV.  相似文献   

9.
Tomato (Solanum lycopersicum) plants exhibiting yellowing, curling and stunting symptoms were identified in fields of the Tawoos Agricultural Systems, in Al‐Batinah in Oman. Cloning and sequencing of restriction endonuclease digested rolling circle amplified viral DNA identified a cotton begomovirus (family Geminiviridae) associated with the symptomatic tomato plants. Detailed analysis of complete sequences showed the virus to be a previously unknown strain of Cotton leaf curl Gezira virus (CLCuGeV) in association with the betasatellite Tomato leaf curl betasatellite (ToLCB). The new CLCuGeV strain, for which the name “Al Batinah” strain is suggested, has the greatest levels of sequence identity (91.9%) to an isolate of CLCuGeV recently reported from the neighbouring United Arab Emirates. Additionally, CLCuGeV‐Al Batinah was shown to have a recombinant origin with sequences donated by an African cassava mosaic virus‐like parent. This is the first identification of this Malvaceae‐adapted begomovirus in tomato. Although ToLCB is common in Oman, being one of only two betasatellites identified there so far, this is the first identification of this betasatellite with CLCuGeV. The significance of these findings is discussed.  相似文献   

10.
The leaf curl disease of tomato was observed in the Haldwani region of Uttarakhand, India during 2004–2007 with an average disease incidence of 49.8 and 73.7% during the month of October and February, respectively. The virus isolate from the infected tomato plants was transmissible to healthy tomato plants by whiteflies (Bemisia tabaci), and the inoculated plants showed typical leaf curl symptoms with a latent period of 16–18 days. The total DNA was extracted from the infected plants and subjected to polymerase chain reaction to amplify the genomic components. The coat protein (CP) gene of ~750 nt was amplified using a set of CP gene specific primer and sequenced (EU847240). Sequence analysis of 701 nt from the N′ terminal region revealed that it had a sequence identity of more than 90% with other isolates/strains of Tomato leaf curl New Delhi virus. A satellite molecule, DNA β of ~1.4 kb was also amplified using universal DNA β-specific primers, cloned and sequenced (EU847239). The isolated DNA β was 1370 nt in length and had a nucleotide sequence identity of 91–93% with DNA β associated with cowpea severe leaf curl and tomato leaf curl disease (TomLCD) reported from India and Pakistan, respectively, and followed by 79% with DNA β associated with TomLCDs reported from Rajasthan. This result showed that the satellite DNA β was associated with TomLCD in Haldwani.  相似文献   

11.
Tomato yellow leaf curl disease (TYLCD) is one of the most devastating viral diseases affecting tomato crops in tropical, subtropical and temperate regions of the world. Here, we focus on the interactions through recombination between the different begomovirus species causing TYLCD, provide an overview of the interactions with the cellular genes involved in viral replication, and highlight recent progress on the relationships between these viruses and their vector, the whitefly Bemisia tabaci. Taxonomy: The tomato yellow leaf curl virus‐like viruses (TYLCVs) are a complex of begomoviruses (family Geminiviridae, genus Begomovirus) including 10 accepted species: Tomato yellow leaf curl Axarquia virus (TYLCAxV), Tomato yellow leaf curl China virus (TYLCCNV), Tomato yellow leaf curl Guangdong virus (TYLCGuV), Tomato yellow leaf curl Indonesia virus (TYLCIDV), Tomato yellow leaf curl Kanchanaburi virus (TYLVKaV), Tomato yellow leaf curl Malaga virus (TYLCMalV), Tomato yellow leaf curl Mali virus (TYLCMLV), Tomato yellow leaf curl Sardinia virus (TYLCSV), Tomato yellow leaf curl Thailand virus (TYLCTHV), Tomato yellow leaf curl Vietnam virus (TYLCVNV) and Tomato yellow leaf curl virus(TYLCV). We follow the species demarcation criteria of the International Committee on Taxonomy of Viruses (ICTV), the most important of which is an 89% nucleotide identity threshold between full‐length DNA‐A component nucleotide sequences for begomovirus species. Strains of a species are defined by a 93% nucleotide identity threshold. Host range: The primary host of TYLCVs is tomato (Solanum lycopersicum), but they can also naturally infect other crops [common bean (Phaseolus vulgaris), sweet pepper (Capsicum annuum), chilli pepper (C. chinense) and tobacco (Nicotiana tabacum)], a number of ornamentals [petunia (Petunia×hybrida) and lisianthus (Eustoma grandiflora)], as well as common weeds (Solanum nigrum and Datura stramonium). TYLCVs also infect the experimental host Nicotiana benthamiana. Disease symptoms: Infected tomato plants are stunted or dwarfed, with leaflets rolled upwards and inwards; young leaves are slightly chlorotic; in recently infected plants, fruits might not be produced or, if produced, are small and unmarketable. In common bean, some TYLCVs produce the bean leaf crumple disease, with thickening, epinasty, crumpling, blade reduction and upward curling of leaves, as well as abnormal shoot proliferation and internode reduction; the very small leaves result in a bushy appearance.  相似文献   

12.
Pedilanthus tithymaloides (Redbird flower) is an ornamental shrub that occasionally exhibits leaf curl and enation symptoms in Pakistan. Symptoms were shown to be associated with a monopartite begomovirus and a betasatellite. The complete nucleotide sequence of the begomovirus was found to be 2764 nucleotides in length and have the highest nucleotide sequence identity to a begomovirus previously isolated from tomato (90.3% nucleotide sequence identity), followed by Radish leaf curl virus (86.3%). The complete betasatellite sequence was determined to be 1358 nucleotides in length and has the highest sequence identity (97%) with Tobacco leaf curl betasatellite . The analysis shows the begomovirus associated with leaf curl disease of Pedilanthus to be a distinct and previously unreported begomovirus for which the name Pedilanthus leaf curl virus (PedLCV) is proposed. This virus is one of an increasing number of monopartite begomoviruses shown to be associated with a betasatellite.  相似文献   

13.
Begomoviruses were detected in leaf samples of Sauropus androgynus (L.) Merr. plants showing leaf curling with or without yellowing symptoms in Kamphaeng Saen, Nakhon Pathom, Thailand in 2009 and 2010. From eight plants with symptoms, 17 complete begomoviral DNA‐As were amplified by polymerase chain reaction and sequenced. No DNA‐B was detected in any of the plants. All the DNA‐As had the characteristic begomovirus genome organization of six open reading frames, two in the virion‐sense orientation and four in the complementary orientation. Sequence comparison of these virus isolates indicated that one isolate belongs to Tomato leaf curl New Delhi virus, 12 isolates belong to Ageratum yellow vein virus and four isolates belong to a novel species with the tentative name Sauropus leaf curl virus. Five of the eight samples were found to be co‐infected by isolates of two different begomovirus species. Recombination analysis indicated that all but one of the isolates were probably the product of one or more recombination events. The results indicated that S. androgynus plants act as natural hosts as well as potential nurseries for genetic recombination between begomovirus species and strains.  相似文献   

14.
The talc-based formulation of two Pseudomonas fluorescens strains (Pf1 and VPT10) and its mixture (with and without chitin) were tested against tomato leaf curl virus in tomato under greenhouse and field conditions. The mean percentage of tomato leaf curl virus infected plants were significantly lower (25%) with less symptom severity and delayed symptom expression up to nine additional days in Pseudomonas with chitin (VPT10 + chitin) treated tomato plants compared to non-bacterised control plants upon challenge inoculation with tomato leaf curl virus. Tomato leaf curl virus was partially purified and antiserum was developed. Using the antiserum the tomato leaf curl virus was detected in symptomatic leaves and in whitefly vector through direct antigen coating enzyme linked immunosorbent assay which revealed the low virus titre in Pseudomonas treated plants (VPT10 + chitin) and insect vector compared to untreated tomato plants. The results indicate the potentiality of plant growth promoting rhizobacteria strains and talc-powder formulations in the effective management of this tomato leaf curl virus in tomato under field conditions.  相似文献   

15.
The complete nucleotide sequence of a satellite molecule associated with Malvastrum leaf curl Guangdong virus (MLCuGdV) infecting M. coromandelianum plants exhibiting leaf curl symptoms in a suburb of Guangzhou, Guangdong Province of China, is described and analysed. The molecule has typical features of betasatellites, containing a single ORF in the complementary‐sense strand, an A‐rich region, the satellite‐conserved region and a stem–loop structure. Compared with the geminivirus betasatellites in GenBank database, this molecule shows the highest nucleotide sequence identity of 71.9% with Tomato leaf curl Philippine betasatellite isolate Laguna1 (ToLCPB, AB307732). Phylogenetic analysis indicates that it is more related to isolate Laguna 1 and Laguna 2 of ToLCPB. According to the proposed species demarcation threshold of betasatellites (78% nucleotide identity), it is a novel betasatellite species, for which we propose the name Malvastrum leaf curl Guangdong betasatellite (MLCuGdB).  相似文献   

16.
Particles of mung bean yellow mosaic virus (MYMV) were purified by a method that yields up to 3 mg per kg of systemically infected Phaseolus vulgaris“Top Crop” and used to prepare antiserum. MYMV antiserum prepared gave a single precipitin line and had a titre of 1/512 with homologous virus in gel double-diffusion tests. MYMV was shown to be serologically related to other whitefly-transmitted viruses, bean golden mosaic virus, tobacco leaf curl virus and cassava latent virus.  相似文献   

17.
Begomoviruses are one of the major pathogens in tomato crops worldwide. In Venezuela, six begomovirus species have been described infecting tomato: Potato yellow mosaic virus (PYMV), Euphorbia mosaic Venezuela virus (EuMVV), Merremia mosaic virus (MeMV), Tomato chlorotic leaf distortion virus (ToCLDV), Tomato yellow margin leaf curl virus (TYMLCV) and Tomato yellow leaf curl virus (TYLCV). In this study, the occurrence of these viruses was analysed by PCR in 338 tomato plants exhibiting virus‐like symptoms. Sixty‐three per cent of the plants were positive at least to one of the begomoviruses tested. PYMV and TYLCV were the most frequent viruses showing 39.6 and 23.7% occurrence, respectively. Phylogenetic analyses revealed two groups of PYMV isolates from several Caribbean Basin countries. The first group clustered isolates from several countries, including Venezuela, and the second group clustered only Colombian isolates. Due to the high prevalence of PYMV and TYLCV in Venezuela, it is suggested that the surveillance and control strategies currently applied in the country should be focused on these two begomoviruses.  相似文献   

18.
Tobacco leaf curl Japan virus, Honeysuckle yellow vein mosaic virus and Tomato yellow leaf curl virus are three begomoviruses that infect tomato crops in Japan. Tomato infection by begomoviruses has increased in Japan after the development of a high level of resistance to certain insecticides in some populations of the vector B. tabaci biotypes ‘B and Q’. Ty‐1 and Ty‐2 homozygous tomato hybrids were evaluated for reaction to monopartite begomovirus species in Japan by Agrobacterium‐mediated inoculation. Test plants were evaluated by a disease assessment scale (DAS), varying from 1 = no symptoms to 4 = severe symptoms, and systemic infection was evaluated by polymerase chain reaction (PCR), using specific begomovirus primers for each virus. Ty‐1 hybrids showed tolerance to HYVMV and with a large number of plants being neither virus‐free nor symptom‐free. The response of Ty‐1 hybrids was also resistant to moderately resistant against TbLCJV. The response of Ty‐2 hybrids was resistant to highly resistant against the three monopartite begomoviruses, when compared with susceptible plants.  相似文献   

19.
A multiplex primer set was developed to detect four Begomoviruses in East Java, Indonesia, i.e. Tomato leaf curl New Delhi virus (ToLCNDV), Tomato yellow leaf curl Kanchanaburi virus (TYLCKaV), Pepper yellow leaf curl Indonesia virus (PepYLCIV) and Mungbean yellow mosaic India virus (MYMIV). Survey at different altitudes found that begomoviruses infecting pepper, tomato and long bean were more variable, while in eggplant and string bean were more uniform. As a single virus, TYLCKaV infected eggplant, and sometimes tomato and pepper; PepYLCIV infected pepper, tomato and long bean; ToLCNDV only infected long bean and tomato at low frequency; and MYMIV infected beans. Mixed infection occurred more frequently in the low altitude areas. Subsequent examination indicated that Cucumber mosaic virus (CMV) and potyviruses were also responsible for diseased fabaceous. Our data suggest a relationship between altitudes and virus species occurrence. However, which viral species infects a crop is mainly influenced by the crop rather than by altitude.  相似文献   

20.
Whitefly-transmitted geminiviruses were found to be associated with four diseases of crop plants in Burkina Faso: cassava mosaic, okra leaf curl, tobacco leaf curl and tomato yellow leaf curl. Tomato yellow leaf curl is an economically serious disease, reaching a high incidence in March, following a peak population of the vector whitefly, Bemisia tabaci, in December. Okra leaf curl is also a problem in the small area of okra grown in the dry season but is not important in the main period of okra production in the rainy season. The geminiviruses causing these four diseases, African cassava mosaic (ACMV), okra leaf curl (OLCV), tobacco leaf curl (TobLCV) and tomato yellow leaf curl (TYLCV) viruses, were each detected in field-collected samples by triple antibody sand-wich-ELISA with cross-reacting monoclonal antibodies (MAbs) to ACMV. Epitope profiles obtained by testing each virus isolate with panels of MAbs to ACMV, OLCV and Indian cassava mosaic virus enabled four viruses to be distinguished. ACMV and OLCV had similar but distinguishable profiles. The epitope profile of TobLCV was the same as that of one form of TYLCV (which may be the same virus) and was close to the profile of TYLCV from Sardinia. The other form of TYLCV reacted with several additional MAbs and had an epitope profile close to that of TYLCV from Senegal. Only minor variations within each of these four types of epitope profile were found among geminivirus isolates from Burkina Faso. Sida acuta is a wild host of OLCV.  相似文献   

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