Tomato Leaf Curl Bangladesh Betasatellite Research Articles

Transreplication Preference of the Tomato Leaf Curl Joydebpur Virus for a Noncognate Betasatellite through Iteron Resemblance on Nicotiana bethamiana.

Pepper plants (Capsicum annuum) with severe leaf curl symptoms were collected in 2013 from Bangalore, Karnataka, India. The detection results showed a co-infection between the tomato leaf curl Joydebpur virus (ToLCJoV) and tomato leaf curl Bangladesh betasatellite (ToLCBDB) through the sequencing analysis of PCR amplicons. To pinpoint the molecular mechanism of this uncommon combination, infectious clones of ToLCJoV and two different betasatellites-ToLCBDB and tomato leaf curl Joydebpur betasatellite (ToLCJoB)-were constructed and tested for their infectivity in Nicotiana benthamiana. Together, we conducted various combined agroinoculation studies to compare the interaction of ToLCJoV with non-cognate and cognate betasatellites. The natural non-cognate interaction between ToLCJoV and ToLCBDB showed severe symptoms compared to the mild symptoms of a cognate combination (ToLCJoV × ToLCJoB) in infected plants. A sequence comparison among betasatellites and their helper virus wasperformed and the iteron resemblances in ToLCBDB as well as ToLCJoB clones were processed. Mutant betasatellites that comprised iteron modifications revealed that changes in iteron sequences could disturb the transreplication process between betasatellites and their helper virus. Our study might provide an important consideration for determining the efficiency of transreplication activity between betasatellites and their helper virus.

A distinct strain of tomato leaf curl New Delhi virus that causes mosaic disease in ash gourd and other cucurbitaceous crops.

Ash gourd (Benincasa hispida) is a cucurbitaceous crop cultivated as an edible vegetable rich in vitamins, minerals, dietary fibers and antioxidants. In a field survey conducted in the Udumalpet region of Tamil Nadu during 2019, the incidence of mosaic disease on ash gourd crop was observed to be 75%. The DNA-A and DNA-B components of begomovirus genome have been identified as associated with this disease. Both the cloned DNA-A and DNA-B genomic components shared highest pairwise sequence identities with the isolates of tomato leaf curl New Delhi virus (ToLCNDV), a bipartite begomovirus. Recombinant analysis showed that both the components are possibly evolved through intra-species recombination between ToLCNDV isolates. Tomato leaf curl Bangladesh betasatellite (ToLCBB) is not naturally associated with this sample. The results of infectivity studies on ash gourd and other cucurbitaceous crops demonstrates the Koch's postulates, when co-inoculation of DNA-A and DNA-B of ToLCNDV was undertaken. However, the inoculation of non-cognate ToLCBB along with DNA-A and DNA-B enhances the symptom expression and reduces the time taken for symptom development. Thus, Koch's postulates were proved for these virus complexes on cucurbitaceous crops. Furthermore, an enhanced accumulation of DNA-A component was detected in the cucurbits co-inoculated with ToLCNDV and ToLCBB. This report highlights the importance of investigating the spread of these disease complexes with other cucurbitaceous crops in India.

Infectivity analysis of chilli leaf curl Ahmedabad virus and its associated tomato leaf curl Bangladesh betasatellite complex in chili

Chilli leaf curl virus is responsible for inducing leaf curl disease in Chili (Capsicum annum L.), with whitefly (Bemisia tabaci) serving as the vector for transmission. Chili leaf samples with leaf curl symptoms were collected from Guntur, Andhra Pradesh, India. PCR-based detection screened for begomoviral infection and betasatellite in the collected samples. In this study, we have characterized tomato leaf curl Bangladesh betasatellite (ToLCBB) (OQ184745) using universal betasatellite primers. Partial dimer constructs were developed using the betasatellite and the DNA A genome of the chilli leaf curl Ahmedabad virus (ChiLCAV) (MW316419) in pCAMBIA 1302 vector. Both the constructs were mobilized separately into the Agrobacterium strain LBA4404, followed by agroinfiltration into healthy chili plants. Plants co-infiltrated with DNA A and betasatellite dimers exhibited symptoms after 21 days of infiltration, whereas plants infiltrated separately with the partial dimer constructs did not display any symptoms. Prominent symptoms include upward curling, thickening of stem ribs and stunted plant growth. Chili plants infiltrated with the infectious clones of ChiLCAV + ToLCBB and ChiLCAV alone showed positive amplification with ChiLCAV-specific and betasatellite primers. In contrast, plants infiltrated with ToLCBB partial dimer construct did not show any amplification with betasatellite primers. ChiLCAV DNA A titer accumulation was further quantified with qPCR and we observed that there is a significant increase (p < 0.0001) in the accumulation level with ChiLCAV + ToLCBB construct when compared to the ChiLCAV construct alone. Thus, this study highlights the pathogenesis of leaf curl disease in C. annuum caused by the begomovirus complex of ChiLCAV and its associated betasatellite ToLCBB.

FIRST REPORT AND GENOME CHARACTERIZATION OF Pepper leaf curl Bangladesh virus INFECTING CHILLI IN INDIA

Chilli (Capsicum annuum L.) leaves showing curling symptoms were collected from Jalandhar region of Punjab, India, and a monopartite begomovirus Pepper leaf curl Bangladesh virus (PepLCBV) associated with Tomato leaf curl Bangladesh betasatellite (ToLCBB) was found to infect the crop. The viral DNA was amplified, cloned and sequenced. Sequencing results revealed that the virus genome and betasatellite consists of 2755 and 1361 nucleotides respectively. Infectious clones of the virus were constructed in binary vector pCAMBIA-1300 and Koch’s postulates were fulfilled. PepLCBV infectious clone caused minor curling in chilli plants when inoculated alone, but it produced typical leaf curl and stunting symptoms in combination with the ToLCBB infectious clone. Phylogenetic analysis with other closely related begomoviruses showed that the present isolate shares high identity with Pepper leaf curl Bangladesh virus. The present isolate grouped with other chilli isolates of begomoviruses reported from India (Pepper leaf curl Lahore virus, Chilli leaf curl Nagpur virus and Tomato leaf curl Liwa virus). Phylogenetic analysis of betasatellite showed its closest identity with Tomato leaf curl Bangladesh betasatellite. It grouped with other betasatellites reported from India (Tomato leaf curl betasatellite, Fenugreek leaf curl betasatellite and Chilli leaf curl betasatellite). Recombination analysis of the virus and betasatellite sequences suggested that PepLCBV might be a recombinant of Chilli leaf curl virus as a major parent and Chilli leaf curl Multan virus as a minor parent, whereas ToLCBB seemed to be a recombinant of Tomato leaf curl betasatellite as a major parent and Tomato leaf curl Ranchi betasatellite as a minor parent. To the best of our knowledge this is the first report of PepLCBV infecting chilli in India.

First Report of Tomato Leaf Curl Bangladesh Virus Associated with Leaf Yellowing Symptoms in Lablab purpureus in Bangladesh

First Report of Tomato Leaf Curl Bangladesh Virus Associated with Leaf Yellowing Symptoms in <i>Lablab purpureus</i> in Bangladesh

Association of Tomato leaf curl New Delhi virus with mosaic and leaf curl disease of Chrysanthemum and its whitefly cryptic species

Leaf samples of chrysanthemum plants showing typical begomovirus symptoms of mosaic, mottling and downward leaf curl were collected from famer’s field in Karnataka state of India. The begomovirus infection was confirmed by PCR using specific primers in twenty two infected chrysanthemum samples and no amplification was observed in twenty two healthy chrysanthemum samples. The partial begomovirus genome (1.2 kb) sequencing indicates, twenty two infected chrysanthemum samples are infected with begomovirus (tomato leaf curl New Delhi virus, ToLCNDV). Therefore one representative sample was selected for complete genome amplification using RCA method. The complete genome amplified was cloned and sequenced. The Species Demarcation Tool (SDT) analysis of full genome of ToLCNDV showed maximum nucleotide (nt) identity of 89.2–97.6% (DNA A) and 87.7–96.3% (DNA B) percent with ToLCNDV infecting cucurbits. Based begomoviruses species demarcation criteria (91% nucleotide sequence identity), the virus infecting chrysanthemum is considered as a strain of ToLCNDV. The betasatellite amplified from the begomovirus infected chrysanthemum showed maximum nt identity of 89% with Tomato leaf curl Bangladesh betasatellite (ToLCBDB) infecting papaya in India. Further, break point recombination analysis showed that genome and betasatellite of ToLCNDV infecting chrysanthemum is recombinant with already know begomoviruses. The whitefly cryptic species predominantly present in the begomovirus infected chrysanthemum fields was identified as Asia-II-5 group. The significance of these findings is discussed.

Genomic characterization and Phylogenetic analysis of Tomato leaf curl virus (ToLCV) from Bangladesh

Tomato leaf curl virus (ToLCV) has frequently emerged as a severe problem for tomato in the recent past, in the tropical and subtropical region of the world. We have cloned and sequenced two isolates of ToLCV responsible for the leaf curl disease of tomato in Bangladesh. Two betasatellite DNAs were associated with ToLCV, and complete nucleotide sequences were determined. The complete genome sequences of ToLCV-[BD:Mym:11] and ToLCV-[BD:Mym2:11] shared the highest nucleotide sequence identities at 95.04 and 92.38%, respectively, with Indian isolate of Tomato leaf curl virus - [India:Ranchi:2007] (ToLCV-[IN:Ran:07]) and Tomato leaf curl Patna virus - [India:Lucknow:2009] (ToLCPatV-[IN:PLuc:09]). Complete nucleotide sequence analysis of the two betasatellite clones, tomato leaf curl betasatellite – [BD:Mym:11] and tomato leaf curl betasatellite – [BD:Mym2:11] associated with (ToLCV-[BD:Mym:11] and (ToLCV-[BD:Mym2:11], when used in BLAST searches respectively revealed 95.51 and 86.43% identity with Tomato leaf curl Bangladesh betasatellite (ToLCBDB-[BD-Gaz-01]) and Tomato leaf curl Patna betasatellite (ToLCPaB-[IN-Pat-07]).

Study of biochemical and histopathological changes induced in the sweet pepper (Capsicum annuum L.) in response to Chilli leaf curl virus infection

A survey was conducted at the horticulture field at Lucknow, India and about 64% leaf curl disease incidence was observed on sweet pepper (Capsicum annuum L.) plants. The severe leaf curl disease was observed in several sweet pepper plants causing deterioration of size and quality of fruit. Therefore, this study was undertaken to characterize the pathogen to cause leaf curl disease in sweet pepper and explore the impact of virus disease on fruit quality of sweet pepper plants. The sequence analysis of full-length genome of detected virus and associated betasatellite isolated from the infected plants revealed the occurrence of Chilli leaf curl virus (ChiLCV) in the association of tomato leaf curl Bangladesh betasatellite (ToLCBDB). The sweet pepper seedlings were co-inoculated with agroinfectious DNA clones of ChiLCV and ToLCBDB which developed similar leaf curl symptom as was observed naturally. The higher accumulation of proline, malondialdehyde, sugar, and polyphenols were observed in virus infected plants as compared to the control. The activities of defense-related enzymes (APx, GPx and SOD) were elevated to cope with the virus-induced stress in infected plants. The fruits in infected plants was deformed compared to control and the nutritional quality of fruits in infected plants was compromised as carotenoids and vitamin-C contents reduced significantly. Moreover, the histopathological evaluations of these symptomatic plants suggested that virus infection severely affects the vascular tissue of leaf and stem. The phenomenon of alterations in the stress related biochemicals of sweet pepper plants due to ChiLCV infection is demonstrated which measures the fruit quality deteriorated by this interaction.

Association of tomato leaf curl Gujarat virus and tomato leaf curl Bangladesh betasatellite on papaya showing typical leaf curl symptoms in North India.

Papaya leaf curl is an economically important disease occurring in papaya growing tropical and subtropical areas. Papaya leaf curl virus, a begomovirus, is the main causative agent for the disease, but many other begomoviruses as well as betasatellites have also been reported on papaya leaf curl disease. Rapidly evolving host range of begomoviruses is a major issue for developing successful resistance strategies against begomoviral infection considering their expanding host range and mixed infection. In our study, we have identified the presence of begomovirus and associated satellite molecule on papaya showing severe leaf curl symptoms in Lucknow, India. Analysis of complete DNA-A component of this isolate (MG757245) revealed the highest similarity (91%) with tomato leaf curl Gujarat virus (ToLCuGuV), while sequence data of betasatellite (MG478451) showed maximum (89%) identity with tomato leaf curl Bangladesh betasatellite (ToLCuBB). This is the first report on identification of ToLCuGuV and ToLCuBB coinfecting papaya plants in Lucknow, Uttar Pradesh (India).

Characterization of a new begomovirus and betasatellite associated with chilli leaf curl disease in India.

Chilli leaf curl disease (ChiLCD) is a serious problem and a major limitation to chilli (Capsicum spp.) cultivation in India. Leaves of a chilli plant showing leaf curl symptoms were collected from the Gonda district in Uttar Pradesh, India, in April, 2013. Full-length genomes of a begomovirus and an associated betasatellite were amplified, cloned and sequenced. The size of the begomovirus genome and the betasatellite were 2760 bp and 1374 bp, respectively. The nucleotide sequence of the begomovirus genome shared maximum identity (89%) with pepper leaf curl Bangladesh virus-India isolate Chhapra (PepLCBV, JN663853), below the threshold for species demarcation. Sequence analysis showed that the begomovirus is a potential recombinant between viruses related to PepLCBV and chilli leaf curl virus (ChiLCV). The name chilli leaf curl Gonda virus (ChiLCGV) is being proposed. The betasatellite associated with ChiLCGV was identified as tomato leaf curl Bangladesh betasatellite (ToLCBDB). Agroinoculation of the viral genome along with betasatellite induced severe leaf curl symptoms in Nicotiana benthamiana. ChiLCGV and ToLCBDB characterized in this study represent a new begomovirus-betasatellite complex infecting Capsicum.

Association of recombinant Chilli leaf curl virus with enation leaf curl disease of tomato: a new host for chilli begomovirus in India

Tomato is widely grown vegetable crop in India and viral diseases are major constraint for its production in the country. The chilli leaf curl virus (ChiLCV) infecting chilli reported from the Indian subcontinent is found associated with tomato enation leaf curl disease in tomato growing areas of India. The leaf samples showing enation leaf curl symptoms were collected from tomato fields located in Sonipet (ten infected and one healthy sample) of Haryana state and Varanasi (five infected and one healthy sample) of Uttar Pradesh state, India. Full length genome of begomovirus and associated betasatellite were amplified, cloned and sequenced. The Viral sequences represented in the begomovirus clones showed 89–100 % nucleotide sequence identity, suggesting that they represent a single species. Comparisons to sequences available in the databases showed nucleotide sequence identities of 87.3–91.8 % for TC-Vns and 87.8–98.4 % for TC287 and TC290, with Indian isolates of ChiLCV. The betasatellite sequences obtained had 83.1–94.1 % identity with tomato leaf curl Bangladesh betasatellite (ToLCBDB). An analysis for recombinant origin of genome and betasatellite showed major part of their genome was likely to be originated by recombination of begomo viruses infecting different host species resulting in evolution of new recombinant virus. The ChiLCV-tom reported in the current study is another distinct strain of ChiLCV identified in tomato causing enation leaf curl disease in India. The significance of these findings is discussed.

Identification and molecular characterization of a new recombinant begomovirus and associated betasatellite DNA infecting Capsicum annuum in India.

Capsicum annuum (Chilli) is a perennial herbaceous plant that is cultivated as an annual crop throughout the world, including India. Chilli leaf curl disease (ChiLCD) is a major biotic constraint, causing major losses in chilli production. During 2014, leaf samples of chilli plants displaying leaf curl disease were collected from the Ahmedabad district of Gujarat, India. These samples were used to isolate, clone and sequence viral genomic DNA and an associated betasatellite DNA molecule. Sequence analysis showed 90.4 % nucleotide sequence identity to the previously reported chilli leaf curl virus-[India:Guntur:2009] (ChiLCV-[IN:Gun:09]. As per ICTV nomenclature rules, ChiLCV-Ahm represents a new species of begomovirus, and we therefore propose the name chilli leaf curl Ahmedabad virus-[India:Ahmedabad:2014] (ChiLCAV-[IN:Ahm:14]). The associated betasatellite DNA showed a maximum of 93.5 % nucleotide sequence identity to a previously reported tomato leaf curl Bangladesh betasatellite and may be named tomato leaf curl Bangladesh betasatellite-[India:Ahmedabad:Chilli:2014].

Synergistic interaction among begomoviruses leads to the suppression of host defense-related gene expression and breakdown of resistance in chilli.

Chilli (Capsicum sp.) is one of the economically important spice and vegetable crops grown in India and suffers great losses due to the infection of begomoviruses. Conventional breeding approaches have resulted in development of a few cultivars of chilli resistant to begomoviruses. A severe leaf curl disease was observed on one such resistant chilli cultivar (Capsicum annuum cv. Kalyanpur Chanchal) grown in the experimental field of the Jawaharlal Nehru University, New Delhi. Four different viral genomic components namely, Chilli leaf curl virus (DNA A), Tomato leaf curl Bangladesh betasatellite (DNA β), Tomato leaf curl New Delhi virus (DNA A), and Tomato leaf curl Gujarat virus (DNA B) were associated with the severe leaf curl disease. Further, frequent association of these four genomic components was also observed in symptomatic plants of other chilli cultivars (Capsicum annuum cv. Kashi Anmol and Capsicum chinense cv. Bhut Jolokia) grown in the experimental field. Interaction studies among the isolated viral components revealed that Nicotiana benthamiana and chilli plants inoculated with four genomic components of begomoviruses exhibited severe leaf curl disease symptoms. In addition, this synergistic interaction resulted in increased viral DNA accumulation in infected plants. Resistant chilli plants co-inoculated with four genomic components of begomoviruses showed drastic reduction of host basal (ascorbate peroxidase, thionin, polyphenol oxidase) and specific defense-related gene (NBS-LRR) expression. Our results suggested that synergistic interaction among begomoviruses created permissive cellular environment in the resistant chilli plants which leads to breakdown of natural resistance, a phenomenon observed for the first time in chilli.

Complexity of begomovirus and betasatellite populations associated with chilli leaf curl disease in India.

Chilli, which encompasses several species in the genus Capsicum, is widely consumed throughout the world. In the Indian subcontinent, production of chilli is constrained due to chilli leaf curl disease (ChiLCD) caused by begomoviruses. Despite the considerable economic consequences of ChiLCD on chilli cultivation in India, there have been scant studies of the genetic diversity and structure of the begomoviruses that cause this disease. Here we report on a comprehensive survey across major chilli-growing regions in India. Analysis of samples collected in the survey indicates that ChiLCD-infected plants are associated with a complex of begomoviruses (including one previously unreported species) with a diverse group of betasatellites found in crops and weeds. The associated betasatellites neither enhanced the accumulation of the begomovirus components nor reduced the incubation period in Nicotiana benthamiana. The ChiLCD-associated begomoviruses induced mild symptoms on Capsicum spp., but both the level of helper virus that accumulated and the severity of symptoms were increased in the presence of cognate betasatellites. Interestingly, most of the begomoviruses were found to be intra-species recombinants. The betasatellites possess high nucleotide variability, and recombination among them was also evident. The nucleotide substitution rates were determined for the AV1 gene of begomoviruses (2.60 × 10- 3 substitutions site- 1 year- 1) and the βC1 gene of betasatellites [chilli leaf curl betasatellite (ChiLCB), 2.57 × 10- 4 substitution site- 1 year- 1; tomato leaf curl Bangladesh betasatellite (ToLCBDB), 5.22 × 10- 4 substitution site- 1 year- 1]. This study underscores the current understanding of Indian ChiLCD-associated begomoviruses and also demonstrates the crucial role of betasatellites in severe disease development in Capsicum spp.

Association of Tomato leaf curl Joydebpur virus and a betasatellite with leaf curl disease of eggplant

Leaf samples (five) from brinjal/eggplant fields showing upward leaf curling symptoms were collected from Varanasi, Uttar Pradesh state, India. The full length genome of begomovirus and associated betasatellite were amplified by PCR, cloned and sequenced. Sequences of homologous DNA-A and its betasatellite in all samples were the same. The samples failed to amplify DNA-B, suggesting that the begomovirus associated with leaf curl disease of eggplant was monopartite. The complete genome (homologous of DNA-A) consists of 2758 nts, whereas the betasatellite has 1352 nts and the genome organization is typical of Old World begomoviruses. The sequence analysis showed high levels of nucleotide sequence identity (79.8–91.7%) of virus with Tomato leaf curl Joydebpur virus (ToLCJoV) infecting chilli in India, suggesting it as a strain of ToLCJoV based on the current ICTV taxonomic criteria for begomovirus strain demarcation. However, the betasatellite associated was identified as a variant of Tomato leaf curl Bangladesh betasatellite (ToLCBDB), with which it shared highest sequence identity of 84.7–94.8%. Phylogenetic analyses of the genome further supported the above results. The recombination analyses of both genome and betasatellite showed that a major part of genome sequences are derived from begomoviruses (ToLCJoV, ChiLCuV, AEV) infecting chilli, tomato, ageratum and betasatellite from PaLCuB as the foremost parents in evolution, suggesting this as a new recombinant virus strain. This is the first report of a monopartite begomovirus and a betasatellite molecule associated with the leaf curl disease of eggplant.

Recombination study using Radish leaf curl virus isolates

Begomovirus isolates, exhibiting identity of 89 and 93% with Radish leaf curl virus (RaLCV), were detected from the leaf curl disease affected okra (Abelmoschus esculentus) plants in Bihar, India. The detected isolates are supposed to be a new strain of RaLCV and therefore are referred to here as RaLCV-Hajipur1 and RaLCV-Hajipur2. Alphasatellite was identified as Cotton leaf curl Burewala alphasatellite (CLCuBuA) and betasatellite as Tomato leaf curl Bangladesh betasatellite (ToLCBDB). The aforementioned RaLCV-Hajipur isolates were used to construct infectious clones. These isolates were inoculated separately or together with alpha- and betasatellites in tobacco. The begomovirus and satellites were isolated from tobacco plants at twenty seven day post inoculation and then sequenced. Analysis of the sequences revealed the presence of a new isolate, referred to here as RaLCV-Hajipur3. Recombination analysis using recombination detection program 3 (RDP3) revealed that the RaLCVHajipur1, RaLCV-Hajipur2 and RaLCV-Hajipur3 had recombinant origin. RDP3 analysis of the RaLCVHajipur3 revealed that the two inoculated isolates (RaLCV-Hajipur1 and RaLCV-Hajipur2) were the probable major and minor parents of the newly detected isolate (RaLCV-Hajipur3).

Virus–vector Relationships, Host Range, Detection and Sequence Comparison of Chilli leaf curl virus Associated with an Epidemic of Leaf Curl Disease of Chilli in Jodhpur, India

AbstractAn 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.

Molecular characterization of Tobacco leaf curl Pusa virus, a new monopartite Begomovirus associated with tobacco leaf curl disease in India

Leaf curl disease of tobacco (TbLCD) is endemic in India. A monopartite Begomovirus, a betasatellite and an alphasatellite were found associated with the disease in Pusa, Bihar. The DNA-A of the Begomovirus associated with TbLCD in Pusa, Bihar was found to comprise of 2707 nt with a typical Old World begomovirus-like genome organization. The full-length sequence of DNA-A [HQ180391] showed that the Pusa isolate is a newly described member of the genus Begomovirus, as it had <89% sequence homology with DNA-A of all the known begomoviruses. The isolate is tentatively named as Tobacco leaf curl Pusa virus [India:Pusa:2010]. The betasatellite (HQ180395) associated with TbLCD in Pusa was identified as a variant of Tomato leaf curl Bangladesh betasatellite [IN:Raj:03], with which it shared 90.4% sequence identity. The alphasatellite (HQ180392) associated with the disease had highest 87% nucleotide sequence identity with Tomato leaf curl alphasatellite. The Begomovirus, betasatellite, and alphasatellite associated with TbLCD in Pusa, Bihar, India were found to be recombinants of extant begomoviruses, betasatellites and alphasatellites spreading in the Indian sub-continent and South-East Asia.

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-β 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-β more efficiently than the heterologous one.