Biological and molecular characterization of a begomovirus associated with yellow mosaic vein mosaic disease of pumpkin from Northern India

The biological and molecular properties of Squash leaf curl China virus from Varanasi, India (SLCCNV-IN[IN:Var:Pum]) were characterized. SLCCNV-IN[IN:Var:Pum] could be transmitted by grafting and through whitefly transmission. The complete DNA-A and DNA-B components were amplified through PCR using specific DNA-A and DNA-B primers. The DNA-A of the isolate was comprised of 2,738 nucleotides, encoding typical six open reading frames, and DNA-B of 2,704 nucleotides, encoding two ORFs. Genome organization of the isolate was typical of an old world bipartite begomovirus. Comparisons showed that DNA-A and its intergenic region have the highest sequence identity (97.6 and 97.4%, respectively) with the SLCCNV-IN[IN:Luc:Pum]; (DQ026296). This data suggested that the isolate is a same begomovirus species for which the name Squash leaf curl China virus-India[India:Varanasi:Pumpkin] is proposed. DNA-B showed maximum sequence identity (89.2%) with SLCCNV-IN[IN:Coi:Pum] (AY184488). Phylogenetic analysis of the present isolate showed close relationship to other cucurbit-infecting geminiviruses. This is the first evidence of occurrence of the bipartite Squash leaf curl China virus associated with severe yellow mosaic disease of pumpkin in northern India.     

Genetic diversity and distribution of tomato-infecting begomoviruses in Iran

The incidence and severity of tomato leaf curl disease (TLCD) is increasing worldwide. Here we assess the diversity and distribution within tomato producing areas of Iran of begomoviruses that cause this disease. Tomato with typical TLCD symptoms and asymptomatic weeds were collected in 2005 and 2006 and tested for the presence of begomovirus DNA using polymerase chain reaction (PCR). Analysis of cloned and sequenced PCR products revealed that both mono- and bipartite begomoviruses are associated with TLCD in Iran. Furthermore, our results confirmed the symptomless infection with mono- and bipartite begomoviruses of two weed species, Chrozophora hierosolymitana Spreng (Euphobiaceae) and Herniaria sp. (Caryophyllaceae). Eighteen Iranian begomovirus isolates were classified into two major groups and two or three subgroups according to the 5′-proximal 200 nucleotides of the coat protein (CP) gene or the N-terminal 600 nucleotides of the Rep gene. Whereas most of the monopartite isolates showed closest similarity to tomato yellow leaf curl virus-Gezira (TYLCV-Ge), the three bipartite isolates were most similar to Tomato leaf curl New Delhi virus (ToLCNDV). Mixed mono- and a bipartite begomovirus infections were detected in both tomato and C. hierosolymitana. Our results indicate that the tomato producing areas in central, southern, and southeastern Iran are threatened by begomoviruses originating from both the Mediterranean basin and the Indian subcontinent.     

Characterization and distribution of tomato yellow margin leaf curl virus, a begomovirus from Venezuela

A begomovirus causing mottling and leaf deformation in tomato from the State of Mérida was cloned and sequenced. The virus has a bipartite genome comprised of a DNA-A (2,572 nucleotides) and a DNA-B (2,543 nucleotides) with a genome organization typical of New World begomoviruses. Both components share a common region of 115 nucleotides with 98 % sequence identity. Phylogenetic analysis indicated that while no virus sequences were closely related, the A component was distantly related to those of two other tomato-infecting viruses, tomato leaf deformation virus and Merremia mosaic virus; and the DNA-B, to those of pepper huasteco yellow vein virus and Rhynchosia golden mosaic Yucatan virus. The DNA-A and DNA-B sequences were submitted to GenBank (accession no. AY508993 and AY508994, respectively) and later accepted by the International Committee on Taxonomy of Viruses as the genome of a member of a unique virus species with the name Tomato yellow margin leaf curl virus (TYMLCV). Tomato (Solanum lycopersicum L. ‘Fl. Lanai’) plants inoculated with cloned TYMLCV DNA-A and DNA-B became systemically infected and showed chlorotic margins and leaf curling. The distribution of TYMLCV in tomato-producing states in Venezuela was determined by nucleic acid spot hybridization analysis of 334 tomato leaf samples collected from ten states using a TYMLCV-specific probe and confirmed by PCR and sequencing of the PCR fragment. TYMLCV was detected in samples from the states of Aragua, Guárico, and Mérida, suggesting that TYMLCV is widely distributed in Venezuela.     

A novel recombinant tomato-infecting begomovirus capable of transcomplementing heterologous DNA-B components

The genome of a tomato-infecting begomovirus from Ranchi, India, was cloned, sequenced and analysed. The viral genome shared 88.3% sequence identity with an isolate belonging to the species Tobacco curly shoot virus (TbCSV), and this virus should therefore be considered a member of a new species, tentatively named Tomato leaf curl Ranchi virus (ToLCRnV). The DNA-?? molecule, which had 74.5% sequence identity with tomato leaf curl Bangladesh betasatellite (ToLCBDB), is named tomato leaf curl Ranchi betasatellite (ToLCRnB). Phylogenetic analysis revealed that ToLCRnV is related to tomato leaf curl Bangladesh virus (ToLCBDV), tobacco curly shoot virus (TbCSV) and tomato leaf curl Gujarat virus (ToLCGV). An infectivity study with ToLCRnV established the monopartite nature of the viral genome, whereas inoculation with ToLCRnB resulted in increased symptom severity. ToLCRnV could transreplicate DNA-B of tomato leaf curl Gujarat virus (ToLCGV) and tomato leaf curl New Delhi virus (ToLCNDV), both in N. benthamiana and tomato, although DNA-B accumulation of was less than with the wild-type combinations. ToLCRnB could be efficiently replicated by DNA-A of both ToLCNDV and ToLCGV. A leaf disk assay suggests that DNA-A could transreplicate the homologous DNA-B and DNA-?? more efficiently than the heterologous one.     

Complete sequences of tomato leaf curl Palampur virus isolates infecting cucurbits in Iran

Tomato leaf curl disease (TLCD) and and tomato yellow leaf curl (TYLCD) is caused by a number of begomovirus species that collectively threaten tomato production worldwide. We report here that an ongoing TLCD and TYLCD epidemic in Iran is caused by variants of tomato leaf curl Palampur virus (ToLCPMV), a newly proposed begomovirus species previously only detected in India. Besides infecting tomatoes, we identified ToLCPMV as the causal agent of a cucurbit disease that has devastated greenhouse cucumber and melon farms in Jiroft, southeastern Iran. We found no convincing evidence that the ToLCPMV DNA-B sequences have been derived through inter-species recombination, however, all of the currently sampled ToLCPMV DNA-A sequences are descendents of a sequence that probably arose through recombination between a ToLCNDV isolate and a currently unsampled geminivirus species that falls outside the ToLCNDV-ToLCPMV cluster. The increasing incidence of ToLCPMV in different cultivated species throughout Iran may signal the emergence of a serious new threat to agricultural production throughout the Middle East. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Sequence characterization of Tomato leaf curl Sinaloa virus and <Emphasis Type="Italic">Tomato severe leaf curl virus</Emphasis>: Phylogeny of New World begomoviruses and detection of recombination

Summary. Diseases caused by begomoviruses (family Geminiviridae, genus Begomovirus) constitute a serious constraint to tomato production in Nicaragua. In this study, the complete nucleotide (nt) sequences of the DNA-A and DNA-B components were determined for the first time for Tomato leaf curl Sinaloa virus (ToLCSinV). In addition, the complete nt sequence was determined for the DNA-A component of two isolates of Tomato severe leaf curl virus (ToSLCV). The genome organization of ToLCSinV and ToSLCV was identical to the bipartite genomes of other begomoviruses described from the Americas. A phylogenetic analysis of DNA-A including 45 begomovirus species showed that the indigenous begomoviruses of the New World can be divided into three major clades and an intermediate group: AbMV clade, SLCV clade, “Brazil clade”, and BGYMV group. Phylogenetic analyses of the DNA-A and DNA-B components and their open reading frames indicated that ToLCSinV and ToSLCV belong to different clades: ToLCSinV to the AbMV clade, and ToSLCV to the SLCV clade. The two Nicaraguan isolates of ToSLCV showed a close relationship with ToSLCV from Guatemala (ToSLCV-[GT96-1]) and Tomato chino La Paz virus (ToChLPV), but differed significantly in the AV1 and AC1 regions, respectively. Computer-based predictions indicated that recombination with another begomovirus had taken place within AV1 of ToSLCV dividing this species into two strains. A high probability was also found that ToChLPV is involved in the evolution of ToSLCV.     

Molecular characterization and experimental host range of an isolate of <Emphasis Type="Italic">Wissadula golden mosaic St. Thomas virus</Emphasis>

Partial genome segments of a begomovirus were previously amplified from Wissadula amplissima exhibiting yellow-mosaic and leaf-curl symptoms in the parish of St. Thomas, Jamaica and this isolate assigned to a tentative begomovirus species, Wissadula golden mosaic St. Thomas virus. To clone the complete genome of this isolate of Wissadula golden mosaic St. Thomas virus, abutting primers were designed to PCR amplify its full-length DNA-A and DNA-B components. Sequence analysis of the complete begomovirus genome obtained, confirmed that it belongs to a distinct begomovirus species and this isolate was named Wissadula golden mosaic St. Thomas virus-[Jamaica:Albion:2005] (WGMSTV-[JM:Alb:05]). The genome of WGMSTV-[JM:Alb:05] is organized similar to that of other bipartite Western Hemisphere begomoviruses. Phylogenetic analyses placed the genome components of WGMSTV-[JM:Alb:05] in the Abutilon mosaic virus clade and showed that the DNA-A component is most closely related to four begomovirus species from Cuba, Tobacco leaf curl Cuba virus, Tobacco leaf rugose virus, Tobacco mottle leaf curl virus, and Tomato yellow distortion leaf virus. The putative Rep-binding-site motif in the common region of WGMSTV-[JM:Alb:05] was observed to be identical to that of Chino del tomate virus-Tomato [Mexico:Sinaloa:1983], Sida yellow mosaic Yucatan virus-[Mexico:Yucatan:2005], and Tomato leaf curl Sinaloa virus-[Nicaragua:Santa Lucia], suggesting that WGMSTV-[JM:Alb:05] is capable of forming viable pseudo-recombinants with these begomoviruses, but not with other members of the Abutilon mosaic virus clade. Biolistic inoculation of test plant species with partial dimers of the WGMSTV-[JM:Alb:05] DNA-A and DNA-B components showed that the virus was infectious to Nicotiana benthamiana and W. amplissima and the cultivated species Phaseolus vulgaris (kidney bean) and Lycopersicon esculentum (tomato). Infected W. amplissima plants developed symptoms similar to symptoms observed under field conditions, confirming that this virus is a causal agent of Wissadula yellow mosaic disease in W. amplissima.     

Transreplication of a Tomato yellow leaf curl Thailand virus DNA-B and replication of a DNAbeta component by Tomato leaf curl Vietnam virus and Tomato yellow leaf curl Vietnam virus

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 DNA-A component and associated with a DNAbeta molecule as well as an additional begomovirus tentatively named Tomato yellow leaf curl Vietnam virus (TYLCVV) consisting also of a DNA-A component were identified. To verify if monopartite viruses occurring in Vietnam and Thailand are able to transreplicate the DNA-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 DNA-B component of TYLCTHV-[AIT] was transreplicated by different DNA-A components of viruses from Vietnam and Thailand in Nicotiana benthamiana and Solanum lycopersicum. Moreover, the TYLCTHV-[AIT] DNA-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 DNAs ranging from 735 to 1457 nucleotides were generated in N. benthamiana from those combinations containing TYLCTHV-[AIT] DNA-B component.     

Tomato yellow leaf curl China virus: monopartite genome organization and agroinfection of plants.

The complete DNA sequence (2734 nucleotides) of the monopartite genome of tomato yellow leaf curl China virus (TYLCCNV), a begomovirus transmitted by the whitefly Bemisia tabaci, was determined. The circular genomic DNA contains six open reading frames (ORFs) encoding proteins of molecular weights >10 kDa, of which two (V1 and V2) are located on the virion-sense strand and four (C1, C2, C3 and C4) on the complementary-sense strand. The ORFs are comparable to those of other whitefly-transmitted begomoviruses with a monopartite genome and to those encoded by DNA-A of bipartite begomoviruses. Sequence comparisons with other geminiviruses showed that TYLCCNV belongs to Begomovirus from the Old World. No putative DNA-B genome was found. Nicotiana species and tomato plants agroinoculated with the TYLCCNV monopartite genome developed typical yellowing and leaf-curling symptoms. The cloned molecule carried all the information needed for virus replication and systemic infection of plants.     

Complete nucleotide sequences of a distinct bipartite begomovirus, bitter gourd yellow vein virus, infecting Momordica charantia

Momordica charantia (Cucurbitaceae), a vegetable crop commonly cultivated throughout Pakistan, and begomoviruses, a serious threat to crop plants, are natives of tropical and subtropical regions of the world. Leaf samples of M. charantia with yellow vein symptoms typical of begomovirus infections and samples from apparently healthy plants were collected from areas around Lahore in 2004. Full-length clones of a bipartite begomovirus were isolated from symptomatic samples. The complete nucleotide sequences of the components of one isolate were determined, and these showed the arrangement of genes typical of Old World begomoviruses. The complete nucleotides sequence of DNA A showed the highest nucleotide sequence identity (86.9%) to an isolate of Tomato leaf curl New Delhi virus (ToLCNDV), confirming it to belong to a distinct species of begomovirus, for which the name Bitter gourd yellow vein virus (BGYVV) is proposed. Sequence comparisons showed that BGYVV likely emerged as a result of inter-specific recombination between ToLCNDV and tomato leaf curl Bangladesh virus (ToLCBDV). The complete nucleotide sequence of DNA B showed 97.2% nucleotide sequence identity to that of an Indian strain of Squash leaf curl China virus.     

Strains of a new bipartite begomovirus, pepper yellow leaf curl Indonesia virus, in leaf-curl-diseased tomato and yellow-vein-diseased ageratum in Indonesia

The complete nucleotide sequences of begomoviruses from pepper with leaf curl and yellowing symptoms, tomato with leaf curl symptoms, and ageratum with yellow vein in Indonesia were determined. On the basis of genome organization and sequence homology, they were proposed to belong to a new species, Pepper yellow leaf curl Indonesia virus (PepYLCIV), which includes the new strains PepYLCIV-Tomato and PepYLCIV-Ageratum. These viruses had bipartite genomes. Pepper virus DNAs from Indonesia (PepYLCIV, PepYLCIV-Tomato and PepYLCIV-Ageratum DNA-As) were noticeably distinct, forming a separate branch from the viruses infecting pepper. Considerable divergence was observed in the common region (CR) of the genomic components of PepYLCIV (77%), PepYLCIV-Tomato (82%) and PeYLCIV-Ageratum (75%). A stem-loop-forming region and a Rep-binding motif were identical in the CR of the three viruses. The CRs of PepYLCIV-Ageratum DNA-A was approximately 10 nucleotides longer than that of PepYLCIV DNA-A and PepYLCIV-Tomato DNA-A. A similar insertion was also found in the CR of PepYLCIV-Ageratum DNA-B. PepYLCIV DNA-A alone was infectious in pepper and Nicotiana benthamiana plants, and association with DNA-B increased symptom severity.     

Molecular characterization of distinct bipartite begomovirus infecting bhendi (Abelmoschus esculentus L.) in India

Yellow vein mosaic disease of okra is a whitefly transmitted begomovirus causing heavy economic loss in different parts of India. The okra isolate (OY131) of this virus from a bhendi plant [(Abelmoschus esculentus L.) Moench] showing yellow vein mosaic, vein twisting, reduced leaves, and a bushy appearance in the Palem region, New Delhi, India, was characterized in the present study. The complete DNA-A and DNA-B sequences have been determined and are comprised of 2,746 and 2,703 nucleotides, respectively. The betasatellite (DNA-β) component was absent in the sample. The genome organization was typically of biparite begomoviruses, which were characterized earlier. Comparison of DNA-A component with other known begomoviruses suggest that this virus, being only distantly related (<85.9% similarity with its nearest relative, BYVMV) to other known begomoviruses, is a new species. We have tentatively assigned the genome to a novel geminivirus species Bhendi yellow vein mosaic Delhi virus [BYVDV-IN (India: Delhi: okra)]. DNA-B showed highest sequence identity (87.8% identical) to that of a ToLCNDV (AY158080). The phylogenetic analysis of the present isolate is distinct from all other viruses; however clusters with ToLCNDV group infect different crops. The recombination analysis revealed that this isolate has sequences originated from ToLCNDV. This is the first known bhendi yellow vein mosaic disease associated bipartite begomovirus from India.     

Characterization of a new begomovirus and a beta satellite associated with the leaf curl disease of French bean in northern India

Begomoviruses are emerging as serious threat to many crops throughout the world particularly in tropical and sub-tropical regions. A leaf curl disease with symptoms typical of infection by many begomoviruses was observed in French bean (Phaseolus vulgaris) at Kanpur, India, during 2010–2012. The disease caused downward leaf curling and made the plants unproductive. The disease was transmitted from infected to healthy plants through whitefly (Bemisia tabaci). The products of five samples digested with EcoRI yielded DNA fragments of about 2.7 kb. The complete sequence of the Fb1 sample comprised 2,741 nucleotides with genome organization typical of begomoviruses having two ORFs in virion-sense and five ORFs in complementary-sense separated by an intergenic region with begomovirus conserved nonanucleotide sequence, TAATATTAC. The complete DNA-A sequence homology was most closely related to Cotton leaf curl Bangalore virus with 80 % nucleotide sequence identity. Based on the demarcation criteria for identifying a begomovirus species, Fb1 is considered as a distinct begomovirus species, named French bean leaf curl virus and designated as FbLCV-[IN:Knp:12]. The complete sequence of associated satellite DNA-β comprises 1,379 nucleotides with single ORF and has 80 % identity with Papaya leaf curl beta satellite. There was no evidence of recombination in DNA-A of FbLCV and associated beta satellite DNA molecule.     

Molecular identification of a new begomovirus associated with yellow mosaic disease of Jatropha gossypifolia in India

Yellow mosaic disease was observed on Jatropha gossypifolia plants growing in Kathaupahadi, Madhya Pradesh, India, and whiteflies (Bemisia tabaci) were found in the vicinity. Association of a new begomovirus with yellow mosaic disease of J. gossypifolia has been detected by PCR using begomovirus DNA-A-specific primers. The complete DNA-A genome (~2.7 kb) of this virus isolate was amplified by rolling-circle amplification (RCA) followed by digestion with Bam HI. The ~2.7-kb amplicons was cloned and sequenced, and the data obtained were submitted to GenBank under accession numbers FJ177030. The genome of the virus isolate consisted of six open reading frames (ORFs): V2 (pre-coat protein) and V1 (coat protein) in the virion sense and C3 (REn protein), C2 (TrAP protein), C1 (replication-associated protein) and C4 (C4 protein) in the complementary sense. BLASTn analysis of the nucleotide sequence (2757 nt) of the viral genome (FJ177030) showed 84–85% identity and a distinct phylogenetic relationship with DNA-A of tomato leaf curl virus-Bangalore II (U38239) and tomato leaf curl Karnataka virus (AY754812). Based on its 85% sequence identity to all other begomoviruses known to date and ICTV species demarcating criteria (< 88% identity), the name Jatropha yellow mosaic India virus (JYMIV) is proposed. JYMIV is considered to be monopartite, as neither DNA-B nor DNA-β components associated with begomoviruses were detected.     

Molecular characterization of a distinct begomovirus infecting tobacco in Yunnan, China

Summary.  Virus isolate Y3V, obtained from tobacco showing leaf curl symptoms in Yunnan, China, had particles with the size and morphology typical of geminiviruses. In reactions with a set of monoclonal antibodies raised against begomoviruses, Y3V was readily differentiated from two previously studied Chinese Begomovirus isolates. The complete nucleotide sequence of a DNA-A-like molecule of Y3V was determined; it comprises 2744 nucleotides and has a typical Begomovirus genome organization. When compared with the DNA-A sequences of other begomoviruses, the total DNA-A of Y3V was most closely related to that of Ageratum yellow vein virus (AYVV) (85% sequence identity), but the Y3V intergenic region differed greatly from those of the other sequences (maximum 70% identity). In contrast, the deduced coat protein of Y3V is most like that of Tomato yellow leaf curl Thailand virus-[1] (TYLCTHV-[1]) (92% amino acid sequence identity). The molecular data show that the Yunnan isolate of Tobacco leaf curl virus is a distinct Begomovirus species, for which the name Tobacco leaf curl Yunnan virus (TLCYnV) is proposed. Received February 27, 2001/Accepted May 29, 2001     

Molecular characterization of tomato-infecting begomoviruses in Thailand

Bipartite geminiviruses infecting tomatoes in Thailand were detected by polymerase chain reaction (PCR) using CPA5/CPA2 primers. Products derived from PCR-amplified full-length DNA-A and DNA-B of TYLCV collected from Chiang Mai, Nong Khai, and Sakon Nakhon were cloned and sequenced. DNA-A from Chiang Mai was 2747 nts long; Nong Khai, 2744 nts; and Sakon Nakhon, 2747 nts, and those of DNA-B from Chiang Mai were 2750 nts long; Nong Khai, 2749 nts; and Sakon Nakhon, 2749 nts. The genomes of these virus isolates were organized like those of other begomoviruses. The DNA-A had two ORFs in the virion sense and four ORFs in the complementary sense. The DNA-B had two ORFs in the virion sense and one ORF in the complementary sense. Nucleotide sequences of DNA-A of TYLCV from Chiang Mai, Nong Khai, and Sakon Nakhon were closely related to those of Tomato yellow leaf curl Thailand virus (TYLCTHV) and Tomato yellow leaf curl Thailand virus-[Myanmar] (TYLCTHV-[MM]) with nucleotide sequence identity ranging from 89% to 95%. Based on sequence comparisons and phylogenetic analyses, these three virus isolates studied were identified as new strains of TYLCTHV and named Tomato yellow leaf curl Thailand virus-Chiang Mai (TYLCTHV-[CM]The GenBank accession codes for DNA-A of TYLCTHV-[CM], -[NK], and -[SK] are , and , respectively. The GenBank accession codes for DNA-B of TYLCTHV-[CM], -[NK], and -[SK] are , , and , respectively.), Nong Khai (TYLCTHV-[NK] and Sakon Nakhon (TYLCTHV-[SK]).     

Molecular characterization of a new begomovirus infecting Sida cordifolia and its associated satellite DNA molecules

Two virus isolates Hn57 and Hn60 were obtained from Sida cordifolia showing mild upward leaf-curling symptoms in Hainan province of China. Comparison of partial sequences of DNA-A like molecule confirmed the existence of a single type of begomovirus. The complete nucleotide sequence of DNA-A of Hn57 was determined to be 2757 nucleotides, with a genomic organization typical of begomoviruses. Complete sequence comparison with other reported begomoviruses revealed that Hn57 DNA-A has the highest sequence identity (71.0%) with that of Tobacco leaf curl Yunnan virus. Consequently, Hn57 was considered to be a new begomovirus species, for which the name Sida leaf curl virus (SiLCV) is proposed. In addition to DNA-A molecule, two additional circular single-stranded satellite DNA molecules corresponding to DNAβ and DNA1 were found to be associated with SiLCV isolates. Both DNAβ and DNA1 were approximately half the size of their cognate genomic DNA. Sequence analysis shows that DNAβ of Hn57 and Hn60 share 93.8% nucleotide sequence identity, and they have the highest sequence identity (58.5%) with DNAβ associated with Ageratum leaf curl disease (AJ316027). The nucleotide sequence identity between DNA1 of Hn57 and that of Hn60 was 83.8%, they share 58.2–79.3% nucleotide sequence identities in comparison with other previously reported DNAl. The GenBank accession numbers of the sequences reported in this paper are AM050730-35.     

Identification and molecular characterization of begomovirus and associated satellite DNA molecules infecting <Emphasis Type="Italic">Cyamopsis tetragonoloba</Emphasis>

Monopartite begomoviruses comprise DNA-A as the main genome and associated satellite DNAs. Viral DNA extracted from guar (Cyamopsis tetragonoloba) showing leaf curl symptoms exhibited positive amplification of coat protein (CP) gene of DNA-A component, suggesting the presence of begomovirus. Full length DNA-A was amplified by primer pair re-designed from CP gene nucleotide sequence. The associated alphasatellite and betasatellite DNA molecules were amplified and sequenced, confirming the presence of monopartite begomovirus. Sequence comparisons showed 89% identity with other begomoviruses. The Neighbor-Joining tree based on full length DNA-A nucleotide sequence showed that the guar infecting begomovirus clustered separately from other known begomoviruses. The betasatellite shared a high (96%) nucleotide identity to Cotton leaf curl Multan betasatellites. The alphasatellite showed 91% nucleotide identity to alphasatellite associated with begomovirus infecting Okra. Recombination analyses showed three recombinant fragments in DNA-A, two in betasatellite, and four in alphasatellite. The results suggest that the begomovirus identified in this study was a new recombinant virus. Its name was proposed as Cyamopsis tetragonoloba leaf curl virus (CyTLCuV).     

A new begomovirus–betasatellite complex is associated with chilli leaf curl disease in Sri Lanka

Leaf curl disease of chilli (LCDC) is a major constraint in production of chilli in the Indian subcontinent. The objective of this study was to identify the begomovirus species occurring in chilli in Sri Lanka, where the LCDC was initially recorded in 1938. The virus samples were collected from the North Central Province, the major chilli growing region in Sri Lanka with a history of epidemic prevalence of LCDC. The virus could be readily transmitted by Bemisia tabaci to chilli, tomato and tobacco, where vein clearing followed by leaf curl developed. The genome analysis of two isolates obtained from two distantly located fields showing 100 % LCDC, revealed that the DNA-A genome (2754 nucleotides) shared 89.5 % sequence identity with each other and 68.80–84.40 % sequence identity with the other begomoviruses occurring in the Indian subcontinent. The closest identity (84.40 %) of the virus isolates was with Tomato leaf curl Sri Lanka virus (ToLCLKV). The results support that a new begomovirus species is affecting chilli in Sri Lanka and the name Chilli leaf curl Sri Lanka virus (ChiLCSLV) is proposed. Recombination analysis indicated that ChiLCSLV was a recombinant virus potentially originated from the begomoviruses prevailing in southern India and Sri Lanka. The genome of betasatellite associated with the two isolates consisted of 1366 and 1371 nucleotides and shared 95.2 % sequence identity with each other and 41.50–73.70 % sequence identity with the other betasatellite species. The results suggest that a new begomovirus betasatellite, Chilli leaf curl Sri Lanka betasatellite is associated with LCDC in Sri Lanka. This study demonstrates a new species of begomovirus and betasatellite complex is occurring in chilli in Sri Lanka and further shows that diverse begomovirus species are affecting chilli production in the Indian subcontinent.     

Tomato chlorotic leaf distortion virus,a new bipartite begomovirus infecting <Emphasis Type="Italic">Solanum lycopersicum</Emphasis> and <Emphasis Type="Italic">Capsicum chinense</Emphasis> in Venezuela

Virus isolate T217L was obtained from a diseased tomato (Solanum lycopersicum) plant showing leaf deformation and chlorotic mottle symptoms near Maracaibo in the state of Zulia, Venezuela. Full-length DNA-A and DNA-B molecules of T217L were cloned and sequenced. The genome organization of T217L was identical to the bipartite genomes of other begomoviruses described from the Americas. Characteristic disease symptoms were reproduced in S. lycopersicum and Capsicum annum plants inoculated using the cloned viral DNA-A and DNA-B components, confirming disease aetiology. A sequence analysis of DNA-A showed that the T217L isolate has the highest sequence identity (84%) with sida yellow mosaic Yucatan virus (SiYMYuV), sida golden mosaic Honduras virus (SiGMHV) and bean dwarf mosaic virus (BDMV) isolates. This is less than the 89% identity in the DNA-A component that has been defined as the threshold value for the demarcation of species in the genus Begomovirus. The molecular data show that isolate T217L belongs to a novel tentative begomovirus species, for which the name tomato chlorotic leaf distortion virus is proposed. TCLDV was also detected in symptomatic C. chinense plants growing near the T217L-infected plant.