Begomovirus
Geminiviridae
Indian Ocean Islands
Malvaceae
Lycopersicon esculentum
Abelmoschus
Ipomoea
DNA, Satellite
Tobacco
Manihot
Ageratum
Hemiptera
Gossypium
Solanum nigrum
Phaseolus
Cucumis
Satellite Viruses
Plant Leaves
Capsicum
Recombination, Genetic
Sequence Analysis, DNA
Molecular Sequence Data
Evolution, Molecular
Cluster Analysis
DNA helicase activity is associated with the replication initiator protein rep of tomato yellow leaf curl geminivirus. (1/170)
The Rep protein of tomato yellow leaf curl Sardinia virus (TYLCSV), a single-stranded DNA virus of plants, is the replication initiator essential for virus replication. TYLCSV Rep has been classified among ATPases associated with various cellular activities (AAA+ ATPases), in superfamily 3 of small DNA and RNA virus replication initiators whose paradigmatic member is simian virus 40 large T antigen. Members of this family are DNA- or RNA-dependent ATPases with helicase activity necessary for viral replication. Another distinctive feature of AAA+ ATPases is their quaternary structure, often composed of hexameric rings. TYLCSV Rep has ATPase activity, but the helicase activity, which is instrumental in further characterization of the mechanism of rolling-circle replication used by geminiviruses, has been a longstanding question. We present results showing that TYLCSV Rep lacking the 121 N-terminal amino acids has helicase activity comparable to that of the other helicases: requirements for a 3' overhang and 3'-to-5' polarity of unwinding, with some distinct features and with a minimal AAA+ ATPase domain. We also show that the helicase activity is dependent on the oligomeric state of the protein. (+info)Synergism of a DNA and an RNA virus: enhanced tissue infiltration of the begomovirus Abutilon mosaic virus (AbMV) mediated by Cucumber mosaic virus (CMV). (2/170)
Replication of the begomovirus Abutilon mosaic virus (AbMV) is restricted to phloem nuclei, generating moderate levels of virus DNA. Co-infection with Cucumber mosaic virus (CMV) evidently increased AbMV titers in Nicotiana benthamiana, tobacco, and tomato, resulting in synergistic symptom enhancement. In situ hybridization revealed that in double-infected leaves an increased number of nuclei contained elevated amounts of AbMV. Additionally, the begomoviral phloem-limitation was broken. Whereas CMV 3a movement protein-expressing tobacco plants did not exert any similar influence, the presence of CMV 2b silencing suppressor protein lead to enhanced AbMV titers and numbers of infected vascular cells. The findings prove that AbMV can replicate in nonvascular cells and represent the first report on a true synergism of an RNA/ssDNA virus combination in plants, in which CMV 2b protein plays a role. They indicate considerable consequences of mixed infections between begomo- and cucumoviruses on virus epidemiology and agriculture. (+info)Suppressor of RNA silencing encoded by Tomato yellow leaf curl virus-Israel. (3/170)
The Israeli isolate of Tomato yellow leaf curl geminivirus (TYLCV-Is) is a major tomato pathogen, causing extensive crop losses both in the New and Old World. Surprisingly, however, little is known about the molecular mechanisms of TYLCV-Is interactions with tomato cells. Here, we have identified a TYLCV-Is protein, V2, which acts as a suppressor of RNA silencing and which is unrelated to presently known viral suppressors. Specifically, V2, but not other proteins of TYLCV-Is, inhibited RNA silencing of a reporter transgene, GFP. This inhibition elevated the cellular levels of the GFP transcript and the GFP protein, but it had no apparent effect on the accumulation of GFP-specific short interfering RNAs (siRNAs), suggesting that TYLCV-Is V2 targets a step in the RNA silencing pathway which is subsequent to the Dicer-mediated cleavage of dsRNA. Visualization of the sub-cellular localization of TYLCV-Is V2 in plant protoplasts and tissues showed that this protein is associated with cytoplasmic strands and inclusion bodies in the cortical regions of the cell. (+info)Founder effect, plant host, and recombination shape the emergent population of begomoviruses that cause the tomato yellow leaf curl disease in the Mediterranean basin. (4/170)
Tomato yellow leaf curl disease (TYLCD)-associated viruses present a highly structured population in the western Mediterranean basin, depending on host, geographical region and time. About 1,900 tomato and common bean samples were analyzed from which 111 isolates were characterized genetically based on a genome sequence that comprises coding and non-coding regions. Isolates of three distinct begomoviruses previously described were found (Tomato yellow leaf curl virus, TYLCV, Tomato yellow leaf curl Sardinia virus, TYLCSV, and Tomato yellow leaf curl Malaga virus, TYLCMalV), together with a novel recombinant virus. Mixed infections were detected in single plants, rationalizing the occurrence of recombinants. Except for TYLCV-type strain, single, undifferentiated subpopulations were present for each virus type, probably the result of founder effects. Limited genetic variation was observed in genomic regions, with selection against amino acid change in coding regions. (+info)Tomato yellow spot virus, a tomato-infecting begomovirus from Brazil with a closer relationship to viruses from Sida sp., forms pseudorecombinants with begomoviruses from tomato but not from Sida. (5/170)
Geminiviruses are characterized by a circular, single-stranded DNA genome and twinned icosahedral particles. Begomoviruses (whitefly-transmitted geminiviruses) are a major constraint to crop production worldwide. In Brazil, tomato-infecting begomoviruses emerged as serious pathogens over the last 10 years, due to the introduction of a new biotype of the insect vector. Tomato yellow spot virus (ToYSV) is a newly described begomovirus originally isolated from tomato, but phylogenetically closer to viruses from Sida sp. A study was performed to determine the viability of pseudorecombinants formed between the DNA components of ToYSV and other weed- and tomato-infecting begomoviruses from Brazil. Despite its closer relationship to weed-infecting viruses, ToYSV was only capable of forming viable pseudorecombinants with tomato viruses. An infectious pseudorecombinant formed between ToYSV DNA-A and tomato crinkle leaf yellows virus (TCrLYV) DNA-B induced severe symptoms in Nicotiana benthamiana. This was attributed, at least in part, to the fact that the origins of replication of both components had identical Rep-binding sequences. However, this was not the case for another infectious pseudorecombinant formed between tomato golden mosaic virus (TGMV) DNA-A and ToYSV DNA-B, which have different Rep-binding sequences. These results reinforce the notion that pseudorecombinant formation cannot be explained solely on the basis of phylogenetic relationships and conserved iteron sequences, and suggest that the TGMV Rep protein may be more versatile in terms of recognizing heterologous DNA components than that of ToYSV. (+info)Tomato chlorotic mottle virus is a target of RNA silencing but the presence of specific short interfering RNAs does not guarantee resistance in transgenic plants. (6/170)
Tomato chlorotic mottle virus (ToCMoV) is a begomovirus found widespread in tomato fields in Brazil. ToCMoV isolate BA-Se1 (ToCMoV-[BA-Se1]) was shown to trigger the plant RNA silencing surveillance in different host plants and, coinciding with a decrease in viral DNA levels, small interfering RNAs (siRNAs) specific to ToCMoV-[BA-Se1] accumulated in infected plants. Although not homogeneously distributed, the siRNA population in both infected Nicotiana benthamiana and tomato plants represented the entire DNA-A and DNA-B genomes. We determined that in N. benthamiana, the primary targets corresponded to the 5' end of AC1 and the embedded AC4, the intergenic region and 5' end of AV1 and overlapping central part of AC5. Subsequently, transgenic N. benthamiana plants were generated that were preprogrammed to express double-stranded RNA corresponding to this most targeted portion of the virus genome by using an intron-hairpin construct. These plants were shown to indeed produce ToCMoV-specific siRNAs. When challenge inoculated, most transgenic lines showed significant delays in symptom development, and two lines had immune plants. Interestingly, the levels of transgene-produced siRNAs were similar in resistant and susceptible siblings of the same line. This indicates that, in contrast to RNA viruses, the mere presence of transgene siRNAs corresponding to DNA virus sequences does not guarantee virus resistance and that other factors may play a role in determining RNA-mediated resistance to DNA viruses. (+info)The oligomeric Rep protein of Mungbean yellow mosaic India virus (MYMIV) is a likely replicative helicase. (7/170)
Geminiviruses replicate by rolling circle mode of replication (RCR) and the viral Rep protein initiates RCR by the site-specific nicking at a conserved nonamer (TAATATT downward arrow AC) sequence. The mechanism of subsequent steps of the replication process, e.g. helicase activity to drive fork-elongation, etc. has largely remained obscure. Here we show that Rep of a geminivirus, namely, Mungbean yellow mosaic India virus (MYMIV), acts as a replicative helicase. The Rep-helicase, requiring > or =6 nt space for its efficient activity, translocates in the 3'-->5' direction, and the presence of forked junction in the substrate does not influence the activity to any great extent. Rep forms a large oligomeric complex and the helicase activity is dependent on the oligomeric conformation ( approximately 24mer). The role of Rep as a replicative helicase has been demonstrated through ex vivo studies in Saccharomyces cerevisiae and in planta analyses in Nicotiana tabacum. We also establish that such helicase activity is not confined to the MYMIV system alone, but is also true with at least two other begomoviruses, viz., Mungbean yellow mosaic virus (MYMV) and Indian cassava mosaic virus (ICMV). (+info)Distinct viral sequence elements are necessary for expression of Tomato golden mosaic virus complementary sense transcripts that direct AL2 and AL3 gene expression. (8/170)
Transient expression studies using Nicotiana benthamiana protoplasts and plants have identified sequences important for transcription of complementary sense RNAs derived from Tomato golden mosaic virus (TGMV) DNA component A that direct expression of AL2 and AL3. Transcription of two complementary sense RNAs, initiating at nucleotides 1,935 (AL1935) and 1,629 (AL1629), is directed by unique sequences located upstream of each transcription initiation site. One element is located between 28 and 124 nucleotides (nt) upstream of the AL1935 transcription start site, which differs from a second element located 150 nt downstream, between 129 and 184 nt upstream of the AL1629 transcription start site. Transcription initiation at nucleotide 1,935 is lower than that at nucleotide 1,629 as determined by run-on transcription assays, and the resulting transcript is only capable of expressing AL3. The transcript initiating at nucleotide 1,629 is capable of directing expression of both AL2 and AL3, although expression of AL3 is up to fourfold greater than that for AL2. Nuclear factors purified from tobacco suspension cells bind to sequences upstream of both AL1935 and AL1629, correlating with the ability of these sequences to direct gene expression. Thus, in tobacco, regulatory sequences direct transcription of two unique TGMV messenger RNAs that differentially express AL2 and AL3. (+info)In the medical field, DNA satellites are small DNA sequences that are associated with larger DNA molecules, such as chromosomes. These satellites are typically repetitive in nature and are found in the non-coding regions of DNA. DNA satellites can play a role in the regulation of gene expression and can also be used as markers for genetic disorders or diseases. In some cases, changes in the structure or composition of DNA satellites can be associated with certain medical conditions, such as cancer or neurological disorders. DNA satellites are also important for the stability and organization of chromosomes within the nucleus of a cell. They can help to hold chromosomes together and prevent them from becoming tangled or misaligned.
In the medical field, "DNA, Viral" refers to the genetic material of viruses, which is composed of deoxyribonucleic acid (DNA). Viruses are infectious agents that can only replicate inside living cells of organisms, including humans. The genetic material of viruses is different from that of cells, as viruses do not have a cellular structure and cannot carry out metabolic processes on their own. Instead, they rely on the host cell's machinery to replicate and produce new viral particles. Understanding the genetic material of viruses is important for developing treatments and vaccines against viral infections. By studying the DNA or RNA (ribonucleic acid) of viruses, researchers can identify potential targets for antiviral drugs and design vaccines that stimulate the immune system to recognize and fight off viral infections.
Viral proteins are proteins that are synthesized by viruses during their replication cycle within a host cell. These proteins play a crucial role in the viral life cycle, including attachment to host cells, entry into the cell, replication of the viral genome, assembly of new viral particles, and release of the virus from the host cell. Viral proteins can be classified into several categories based on their function, including structural proteins, non-structural proteins, and regulatory proteins. Structural proteins are the building blocks of the viral particle, such as capsid proteins that form the viral coat. Non-structural proteins are proteins that are not part of the viral particle but are essential for viral replication, such as proteases that cleave viral polyproteins into individual proteins. Regulatory proteins are proteins that control the expression of viral genes or the activity of viral enzymes. Viral proteins are important targets for antiviral drugs and vaccines, as they are essential for viral replication and survival. Understanding the structure and function of viral proteins is crucial for the development of effective antiviral therapies and vaccines.
Begomovirus
Ageratum yellow vein virus
Solanum apical leaf curling virus
Oxalis debilis
Bhendi yellow vein mosaic virus
Abutilon mosaic virus
Alphasatellite
Cassava mosaic virus
Whitefly
Chilli leaf curl virus
Sweet potato leaf curl virus
Φ29 DNA polymerase
Pepper leaf curl virus
Tobacco leaf curl virus
Tomato leaf curl China virus
Papaya leaf curl virus
Tomato yellow leaf curl virus
Clerodendrum golden mosaic China virus
Pepper mild tigré virus
Tomato yellow leaf curl China virus
Mungbean yellow mosaic virus
Indian cassava mosaic virus
Abutilon yellows virus
Bean calico mosaic virus
Cotton leaf curl virus
Beet curly top virus
Geminiviridae
Euphorbia mosaic virus
List of virus genera
African cassava mosaic virus
Begomovirus prevalence and diversity in the TYLCV resistant tomato cultivar Shanty in Nicaragua - Epsilon Archive for Student...
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Table 3 Resistance to Tomato Yellow Leaf Curl Virus in Tomato Germplasm.docx
Whitefly transmitted1
- Sweet potato leaf curl virus (SPLCV), a sweetpotato whitefly transmitted begomovirus, could potentially cause serious yield losses to many sweetpotato cultivars. (usda.gov)
Geminiviridae3
- ES] El virus del rizado de tomate de Nueva Delhi (Tomato leaf curl New Delhi virus, ToLCNDV) pertenece al género Begomovirus englobado en la familia Geminiviridae. (upv.es)
- La enfermedad de la vena amarilla de Ageratum está causada por un complejo de ADN vírico de un begomovirus (GEMINIVIRIDAE). (bvsalud.org)
- Yellow vein disease of Ageratum is caused by a viral DNA complex of a begomovirus (GEMINIVIRIDAE). (bvsalud.org)
Leaf curl2
- This study aimed to investigate whether a widely distributed bipartite begomovirus, tomato leaf curl New Delhi virus (ToLCNDV), can maintain cotton leaf curl Multan alphasatellite (CLCuMuA) in the presence or absence of cotton leaf curl Multan betasatellite (CLCuMuB). (bvsalud.org)
- Pepper yellow leaf curl virus (PYLCV) merupakan salah satu anggota dari kelompok Begomovirus, yang menyebabkan penyakit penting pada tanaman cabai di Indonesia. (ipb.ac.id)
Species2
- Restriction analysis with the three restriction enzymes EcoRI, SalI and HpaII, showed mixed infection (more than one begomovirus species present in the tomato plant) in ~80% of the analysed samples. (slu.se)
- Molecular data showed that Hn51 was a new begomovirus species, for which the name Alternanthera yellow vein virus was proposed. (eppo.int)
Viral1
- The results showed that the most common tomato producing areas in Nicaragua (Sebaco, CNIAB, Las Playitas, Tecolostote) still are heavily exposed to begomovirus infections and that mixed viral infections are relatively common in these regions. (slu.se)
TYLCV1
- This is the first identification of TYLCV with ToLCB and the legume adapted bipartite begomovirus MYMIV co-infecting tomato. (bvsalud.org)
Tomato4
- Every year begomovirus infections cause severe constraints to the tomato production in Nicaragua. (slu.se)
- During recent years the use of begomovirus resistant or tolerant tomato cultivars has increased in Nicaragua as an effort to improve yields. (slu.se)
- Still, begomovirus infection is a large threat to the tomato production. (slu.se)
- Therefore, ongoing work in Nicaragua is focusing on finding new, better, begomovirus tolerant or resistant tomato cultivars. (slu.se)
Virus1
- Surprisingly the NGS results also suggested the presence of the bipartite, legume-adapted begomovirus Mungbean yellow mosaic Indian virus (MYMIV). (bvsalud.org)
Plants1
- Infection was also detected in plants, which had been collected without any visible symptoms of begomovirus infections. (slu.se)
Leaf Curl1
- This study aimed to investigate whether a widely distributed bipartite begomovirus, tomato leaf curl New Delhi virus (ToLCNDV), can maintain cotton leaf curl Multan alphasatellite (CLCuMuA) in the presence or absence of cotton leaf curl Multan betasatellite (CLCuMuB). (bvsalud.org)