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1.
Arch Virol ; 164(11): 2873-2875, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31432269

RESUMO

A novel bipartite begomovirus infecting begomovirus-resistant tomato plants was detected via Illumina sequencing analysis, and its genome sequence was confirmed by Sanger sequencing. The DNA-A (2627 nt) and DNA-B (2587 nt) have a genome organization that is typical of New World bipartite begomoviruses, sharing 82.5% identity with tomato golden leaf distortion virus and 75.1% identity with sida chlorotic vein virus. Based on the current classification criteria for begomoviruses, this isolate should be considered a member of a new species, and the name "tomato interveinal chlorosis virus-2" (ToICV2) is proposed for this virus.


Assuntos
Begomovirus/classificação , Begomovirus/genética , Genoma Viral/genética , Lycopersicon esculentum/virologia , Sequência de Bases , Begomovirus/isolamento & purificação , Brasil , DNA Viral/genética , Doenças das Plantas/virologia , Análise de Sequência de DNA , Sequenciamento Completo do Genoma
2.
Arch Virol ; 164(11): 2805-2810, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31451963

RESUMO

Physalis peruviana is a perennial solanaceous plant that has recently been established as a commercial crop in Brazil. This work reports the near-complete genome sequence, particle morphology, and plant host responses to a putative new sobemovirus, named "physalis rugose mosaic virus". The virus, characterized by isometric particles of ca. 30 nm in diameter, causes foliar symptoms of mosaic, malformation and blistering, accompanied by stunting. The near-complete genome sequence comprises 4175 nucleotides and contains five open reading frames that are similar to those of other sobemoviruses. In addition to P. peruviana, the new virus systemically infected Capsicum annuum, Nicotiana tabacum and Solanum lycopersicum by mechanical inoculation. Thus, this virus may cause disease in these crops in the field.


Assuntos
Genoma Viral/genética , Vírus do Mosaico/classificação , Vírus do Mosaico/crescimento & desenvolvimento , Physalis/virologia , Doenças das Plantas/virologia , Vírus de Plantas/classificação , Vírus de Plantas/genética , Brasil , Capsicum/virologia , Lycopersicon esculentum/virologia , Vírus do Mosaico/genética , Vírus de Plantas/crescimento & desenvolvimento , RNA Viral/genética , Tabaco/virologia
3.
J Agric Food Chem ; 67(33): 9241-9253, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31369258

RESUMO

Antiviral compounds targeting viral replicative processes have been studied as an alternative for the control of begomoviruses. Previously, we have reported that the peptide AmPep1 has strong affinity binding to the replication origin sequence of tomato yellow leaf curl virus (TYLCV). In this study, we describe the mechanism of action of this peptide as a novel alternative for control of plant-infecting DNA viruses. When AmPep1 was applied exogenously to tomato and Nicotiana benthamiana plants infected with TYLCV, a decrease in the synthesis of the two viral DNA strands (CS and VS) was observed, with a consequent delay in the development of disease progress in treated plants. The chemical mechanism of action of AmPep1 was deduced using Raman spectroscopy and molecular modeling showing the formation of chemical interactions such as H bonds and electrostatic interactions and the formation of π-π interactions between both biomolecules contributing to tampering with the viral replication.


Assuntos
Amaranthus/química , Antivirais/química , Antivirais/farmacologia , Begomovirus/efeitos dos fármacos , Peptídeos/química , Peptídeos/farmacologia , RNA Viral/química , Replicação Viral/efeitos dos fármacos , Begomovirus/química , Begomovirus/genética , Begomovirus/fisiologia , Sequências Repetidas Invertidas/efeitos dos fármacos , Lycopersicon esculentum/virologia , Doenças das Plantas/virologia , Proteínas de Plantas/química , RNA Viral/genética , Tabaco/virologia
4.
Arch Virol ; 164(9): 2379-2383, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31203434

RESUMO

During 2017, leaf samples of chili pepper (Capsicum annuum), tomato (Solanum lycopersicum), and tobacco (Nicotiana tabacum) plants exhibiting yellowing and curling symptoms were collected from Aceh province, Indonesia. These samples were used to isolate and sequence viral genomic DNA. Six isolates with complete DNA-A and DNA-B sequences of begomovirus were obtained, all of which showed >99% sequence identity to the others. DNA-A sequences shared the highest nucleotide sequence identity (89.3%-89.7%) with monopartite pepper yellow leaf curl Indonesia virus 2 (PepYLCIV2) and the second-highest sequence identity (87.3%-87.4%) with bipartite pepper yellow leaf curl Indonesia virus (PepYLCIV). The DNA-B sequences shared the highest nucleotide sequence identity (95%-97.5%) with PepYLCIV. Results of recombination analysis indicated that the novel begomovirus was a recombinant. In accordance with the guidelines for begomovirus species demarcation, these isolates should be assigned to a new species, and we have proposed the name ''pepper yellow leaf curl Aceh virus'' (PepYLCAV) for this virus.


Assuntos
Begomovirus/isolamento & purificação , Capsicum/virologia , Lycopersicon esculentum/virologia , Doenças das Plantas/virologia , Tabaco/virologia , Begomovirus/classificação , Begomovirus/genética , Genoma Viral , Indonésia , Filogenia , Recombinação Genética , Análise de Sequência de DNA
5.
J Sci Food Agric ; 99(12): 5541-5549, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31106435

RESUMO

BACKGROUND: The production of fruit and vegetables rich in health-promoting components in an eco-friendly context represents the winning answer to the world population demand for food. In this study, the effects of different treatments on the yield and fruit chemical characteristics of tomato (Solanum lycopersicum L.) are reported. The treatments included three inducers of plant defence responses (chitosan, Trichoderma harzianum T-22 and Bacillus subtilis QST713) applied alone or before Cucumber mosaic virus infection. Fruit production and antioxidant compounds were investigated by ultrahigh-performance liquid chromatography (UHPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). RESULTS: Compared to control fruit harvested from untreated and healthy plants, treatment with QST713 increased the fruit number. Furthermore, plant treatments with T22, QST713 and chitosan alone enhanced fruit carotenoids (lutein and ß-carotene), ascorbic acid and phenolic acids (caffeoyl glucoside and p-coumaroyl glucoside). In parallel, compared to fruit harvested from only CMV-infected plants, treatments with T22, QST713 and chitosan before CMV enhanced fruit ascorbic acid and flavonoids (quercetin 3-O-xylosyl-rutinoside and rutin). CONCLUSION: Antioxidant compounds of tomato fruit can increase with the application of the plant defence inducers, thus protecting both the consumer and plant health. © 2019 Society of Chemical Industry.


Assuntos
Antioxidantes/química , Cucumovirus/fisiologia , Lycopersicon esculentum/química , Lycopersicon esculentum/virologia , Doenças das Plantas/virologia , Inoculantes Agrícolas/fisiologia , Ácido Ascórbico/análise , Bacillus subtilis/fisiologia , Carotenoides/análise , Cromatografia Líquida , Frutas/química , Frutas/microbiologia , Frutas/virologia , Lycopersicon esculentum/microbiologia , Espectrometria de Massas em Tandem , Trichoderma/fisiologia
6.
Plant Dis ; 103(6): 1391-1396, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31070546

RESUMO

The genomic, biological, and serological characterization of tomato necrotic spot virus (ToNSV), a virus first described infecting tomato in California, was completed. The complete genomic sequence identified ToNSV as a new subgroup 1 ilarvirus distinct from the previously described tomato-infecting ilarviruses. We identified ToNSV in Indiana in 2017 and 2018 and in Ohio in 2018. The coat protein coding region of the isolates from California, Indiana, and Ohio have 94 to 98% identity, while the same isolates had 99% amino acid identity. ToNSV is serologically related to TSV, a subgroup 1 ilarvirus, and shows no serological relationship to ilarviruses in the other subgroups. In tomato, ToNSV caused symptoms of necrotic spots and flecks on leaves, necrotic streaking on stems, and necrotic spots and circular patterns on fruit resulting in a yield loss of 1 to 13%. These results indicate that ToNSV is a proposed new subgroup 1 ilarvirus causing a necrotic spotting disease of tomato observed in California, Indiana, and Ohio.


Assuntos
Ilarvirus , Lycopersicon esculentum , Filogenia , Frutas/virologia , Genoma Viral/genética , Ilarvirus/classificação , Ilarvirus/genética , Ilarvirus/fisiologia , Lycopersicon esculentum/virologia , Doenças das Plantas/virologia , Estados Unidos
7.
Plant Dis ; 103(7): 1525-1535, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31012822

RESUMO

Rasta is a virus-like disease of unknown etiology affecting tomato (Solanum lycopersicum) plants in Ghana. Symptoms include stunting; epinasty, crumpling, and chlorosis of leaves; and necrosis of leaf veins, petioles, and stems. Leaf samples with rasta symptoms were collected from commercial tomato fields in Ghana in October 2012 and applied to FTA cards, and RNA extracts were prepared. Reverse-transcription polymerase chain reaction (RT-PCR) tests with primers for Columnea latent viroid, which causes rasta-like symptoms in tomato plants in Mali, were negative, whereas tests with degenerate viroid primer pairs were inconclusive. However, tomato seedlings (Early Pak 7) mechanically inoculated with RNA extracts of 10 of 13 samples developed rasta-like symptoms. In RT-PCR tests with RNA from leaves of the 10 symptomatic seedlings and primers for Potato spindle tuber viroid (PSTVd) or Tomato apical stunt viroid (TASVd), the expected size (approximately 360 bp) of DNA fragment was amplified from eight and two seedlings, respectively. Sequence analyses confirmed that these fragments were from PSTVd and TASVd isolates, and revealed a single PSTVd haplotype and two TASVd haplotypes. The PSTVd and TASVd isolates from Ghana had high nucleotide identities (>94%) with isolates from other geographic regions. In a host range study, PSTVd and TASVd isolates from Ghana induced rasta symptoms in the highly susceptible tomato cultivar Early Pak 7 and mild or no symptoms in Glamour, and symptomless infections in a number of other solanaceous species. PSTVd and TASVd isolates were seed associated and possibly seed transmitted.


Assuntos
Lycopersicon esculentum , Vírus de Plantas , Viroides , Sequência de Bases , Gana , Lycopersicon esculentum/virologia , Mali , Vírus de Plantas/fisiologia , Viroides/fisiologia
8.
Pak J Biol Sci ; 22(2): 83-94, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30972990

RESUMO

BACKGROUND AND OBJECTIVE: Tomato Chlorosis Virus (ToCV) is a white fly-transmitted and phloem-limited crinivirus reported in this study for the first time in Egypt. ToCV caused drastic reduction in tomato yield since 2013. The aim of this study is to characterize the virus incidence using biological, serological and molecular tools. MATERIAL AND METHODS: The B. tabaci MEAM1 white fly was used for virus isolation and propagation. Identity of ToCV , its natural hosts were confirmed with RT-PCR using a specific primer pair for ToCV-heat shock protein 70 homologue (HSP70h) gene, sequencing and phylogenetic studies. ToCV was purified using the innovative electro-elution technique. The induced antiserum for the Egyptian isolate of the virus (ToCV-Giza) was used for DAS-ELISA and dot blotting immuno-assays to evaluate the virus presence in tomato and other natural hosts. RESULTS: The ToCV-Giza isolate was donated an accession number "MH667315.1" from the GenBank. Blastx sequence analysis of the HSP70h gene indicated 97-99% of amino acid similarities with many tested ToCV isolates. Phylogenetic studies showed the clustering of all ToCV isolates including ToCV-Giza in a separate group from the other tested criniviruses. The virus had a UV spectrum of a nucleoprotein with Amax and Amin at 260 and 240 nm, respectively and A260/280 ratio of 1.33. Out of 52 different tested plant species within 22 families, 44 were positive hosts for ToCV. Thirty seven out of these 44 plant species were considered as new hosts for ToCV in the present study. These included Ammi majus and Coriandrum sativum (Apiaceae), cabbage (Brassicaceae), sweet potato (Convolvulaceae), melon, cucumber, luffa (Cucurbitaceae), soybean, cowpea, faba bean (Fabaceae), Egyptian and American Cotton (Malvaceae). Several ornamentals either herbal type or woody trees belonging to Acanthaceae, Amaranthaceae, Euophorbiaceae, Moraceae and Rubiaceae were also recognized for the first time as hosts for ToCV. CONCLUSION: The obtained results confirmed the wide distribution of ToCV in its natural hosts in Egypt. Hygienic measures including control of the virus vector and removing of natural hosts should be strictly implicated.


Assuntos
Crinivirus/genética , Lycopersicon esculentum/virologia , Doenças das Plantas/virologia , Animais , Egito , Hemípteros/virologia , Insetos Vetores/virologia , Filogenia
9.
Virology ; 531: 240-247, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30933715

RESUMO

Begomoviruses contain some of the most damaging viral disease agents of crops worldwide, and are transmitted by whiteflies of the Bemisia tabaci species complex. During the last 20 years, transovarial transmission of tomato yellow leaf curl virus (TYLCV) has been reported in two invasive species of the B. tabaci complex. To further decipher the importance of this mode of transmission, we analyzed transovarial transmission of TYLCV by seven whitefly species indigenous to China. TYLCV virions were detected in eggs of all species except one, and in nymphs of two species, but in none of the ensuing adults of all seven species. Our results suggest that these indigenous whiteflies are unable to transmit TYLCV, a begomovirus alien to China, via ova to produce future generations of viruliferous adults, although most of the species exhibit varying ability to carry over the virus to the eggs/nymphs of their offspring via transovarial transmission.


Assuntos
Begomovirus/fisiologia , Hemípteros/fisiologia , Hemípteros/virologia , Insetos Vetores/fisiologia , Insetos Vetores/virologia , Lycopersicon esculentum/virologia , Doenças das Plantas/virologia , Animais , China , Hemípteros/classificação , Hemípteros/genética , Insetos Vetores/classificação , Insetos Vetores/genética
10.
J Agric Food Chem ; 67(26): 7243-7248, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31026153

RESUMO

Tomato chlorosis virus (ToCV) is a newly reported plant virus that has rapidly spread to all parts of the world, resulting in a serious decline in tomato quality and yield due to the lack of effective control agents. In this study, the ToCV coat protein (ToCVCP) was expressed and purified in Escherichia coli, and a series of novel glucopyranoside derivatives containing a dithioacetal moiety was designed and synthesized. The binding affinity of these compounds to ToCVCP was determined using microscale thermophoresis. Results revealed that compounds 6b and 8a interacted with ToCVCP with Kd values of 0.12 and 0.21 µM, respectively. Quantitative reverse transcription polymerase chain reaction was used to evaluate the anti-ToCV activity of 6b and 8a in vivo, and both significantly reduced the expression level of ToCVCP gene in tomato compared with commercial antivirus agents. This study provides an efficient and convenient screening method for anti-ToCV agents and reliable support for the development of novel agrochemicals for ToCV.


Assuntos
Antivirais/farmacologia , Proteínas do Capsídeo/genética , Crinivirus/efeitos dos fármacos , Glucosídeos/farmacologia , Lycopersicon esculentum/virologia , Doenças das Plantas/virologia , Antivirais/síntese química , Antivirais/química , Proteínas do Capsídeo/metabolismo , Crinivirus/genética , Crinivirus/metabolismo , Glucosídeos/síntese química , Glucosídeos/química , Estrutura Molecular
11.
Arch Virol ; 164(6): 1661-1665, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30949815

RESUMO

Forty-five papaya samples showing severe leaf curl symptoms were tested by PCR with a degenerate primer set for virus species in the genus Begomovirus. Of these, 29 were positive for tomato leaf curl Bangladesh virus (ToLCBV). The complete genome sequences of ToLCBV (GenBank accession no. MH380003) and its associated tomato leaf curl betasatellite (ToLCB) (MH397223) from papaya isolate Gaz17-Pap were determined and characterized. Defective betasatellites were found in ToLCBV-positive papaya isolates Gaz19-Pap, Gaz20-Pap and Gaz21-Pap. This study confirmed that papaya is a host of ToLCBV, ToLCB, and other defective and recombinant DNA satellites in Bangladesh.


Assuntos
Begomovirus/isolamento & purificação , Carica/virologia , Doenças das Plantas/virologia , Análise de Sequência de DNA/métodos , Bangladesh , Begomovirus/genética , Begomovirus/patogenicidade , Genoma Viral , Lycopersicon esculentum/virologia , Filogenia , Vírus Satélites/genética , Vírus Satélites/isolamento & purificação , Vírus Satélites/patogenicidade
12.
Dokl Biochem Biophys ; 484(1): 52-54, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31012013

RESUMO

To enhance the synthesis of antigenic envelope proteins L1 of high-grade papillomavirus types HPV16, HPV18, HPV31, and HPV45, the sequence of the gene encoding the cucumber mosaic virus replicase (RdRP CMV) was inserted into the genetic construct. This made it possible to increase the production of these antigenic proteins to 25-27 µg/mg total soluble protein.


Assuntos
Cucumovirus , Epitopos , Lycopersicon esculentum , Papillomaviridae/genética , Vacinas contra Papillomavirus , Proteínas Virais , Cucumovirus/genética , Cucumovirus/metabolismo , Epitopos/biossíntese , Epitopos/química , Epitopos/genética , Lycopersicon esculentum/química , Lycopersicon esculentum/genética , Lycopersicon esculentum/metabolismo , Lycopersicon esculentum/virologia , Vacinas contra Papillomavirus/biossíntese , Vacinas contra Papillomavirus/química , Vacinas contra Papillomavirus/genética , Proteínas Virais/biossíntese , Proteínas Virais/química , Proteínas Virais/genética
13.
Arch Virol ; 164(7): 1897-1901, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30972592

RESUMO

Two begomoviruses were isolated in the northern Brazilian state of Pará, infecting non-cultivated Hibiscus sp. and cultivated tomato (Solanum lycopersicum). The complete genomes (DNA-A and DNA-B) of the two viruses showed the typical organization of New World bipartite begomoviruses. Based on the species assignment criteria in the genus Begomovirus, each virus is a member of a new species. The virus from Hibiscus is most closely related to sida yellow mosaic Yucatan virus, while the tomato virus is most closely related to abutilon mosaic Brazil virus and corchorus mottle virus. Recombination events were detected in the DNA-A of the tomato virus, but not in the Hibiscus virus genome. We propose the names "hibiscus golden mosaic virus" (HGMV) and "tomato chlorotic leaf curl virus" (ToCLCV) for the viruses reported in this study.


Assuntos
Begomovirus/classificação , Begomovirus/genética , Hibiscus/virologia , Lycopersicon esculentum/virologia , Doenças das Plantas/virologia , Begomovirus/isolamento & purificação , Brasil , DNA Viral/genética , Genoma Viral/genética , Homologia de Sequência do Ácido Nucleico
14.
Arch Virol ; 164(7): 1753-1760, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31025116

RESUMO

The expression of several structural proteins from a wide variety of viruses in heterologous cell culture systems results in the formation of virus-like particles (VLPs). These VLPs structurally resemble the wild-type virus particles and have been used to study viral assembly process and as antigens for diagnosis and/or vaccine development. Tomato blistering mosaic virus (ToBMV) is a tymovirus that has a 6.3-kb positive-sense ssRNA genome. We have employed the baculovirus expression vector system (BEVS) for the production of tymovirus-like particles (tVLPs) in insect cells. Two recombinant baculoviruses containing the ToBMV wild-type coat protein (CP) gene or a modified short amino-terminal deletion (Δ2-24CP) variant were constructed and used to infect insect cells. Both recombinant viruses were able to express ToBMV CP and Δ2-24CP from infected insect cells that self-assembled into tVLPs. Therefore, the N-terminal residues (2-24) of the native ToBMV CP were shown not to be essential for self-assembly of tVLPs. We also constructed a third recombinant baculovirus containing a small sequence coding for the major epitope of the chikungunya virus (CHIKV) envelope protein 2 (E2) replacing the native CP N-terminal 2-24 amino acids. This recombinant virus also produced tVLPs. In summary, ToBMV VLPs can be produced in a baculovirus/insect cell heterologous expression system, and the N-terminal residues 2-24 of the CP are not essential for this assembly, allowing its potential use as a protein carrier that facilitates antigen purification and might be used for diagnosis.


Assuntos
Baculoviridae/genética , Proteínas do Capsídeo/biossíntese , Tymovirus/crescimento & desenvolvimento , Tymovirus/genética , Proteínas do Envelope Viral/biossíntese , Montagem de Vírus/genética , Animais , Proteínas do Capsídeo/genética , Linhagem Celular , Vírus Chikungunya/genética , Expressão Gênica/genética , Lycopersicon esculentum/virologia , Mariposas/citologia , Proteínas do Envelope Viral/genética
15.
Plant Dis ; 103(6): 1181-1188, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30908127

RESUMO

Epidemics of tomato yellow leaf curl disease (TYLCD) caused by tomato yellow leaf curl-like begomoviruses (genus Begomovirus, family Geminiviridae) severely damage open field and protected tomato crops worldwide. Intensive application of insecticides against the whitefly vector Bemisia tabaci is generally used as control strategy to reduce TYLCD impact. This practice, however, is frequently ineffective and has a negative impact on the environment and human health. TYLCD-resistant varieties are commercially available, but cultivation of susceptible traditional tasting ones is also requested if possible. For susceptible tomatoes, here we show that using whitefly optical barriers by means of UV-blocking plastics in protected crops can contribute to reducing TYLCD damage and increasing commercial fruit yield. Moreover, induction of systemic acquired resistance by application of the elicitor of plant defense acibenzolar-S-methyl was effective to reduce yield losses when viral pressure was moderate. Interestingly, combining both practices in protected tomato crops can result in a significant TYLCD control. Therefore, these control practices are proposed to be used commercially as management alternatives to include in integrated management of TYLCD.


Assuntos
Begomovirus , Resistência à Doença , Hemípteros , Lycopersicon esculentum , Animais , Begomovirus/fisiologia , Produtos Agrícolas/virologia , Hemípteros/virologia , Lycopersicon esculentum/virologia
16.
Viruses ; 11(2)2019 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-30813271

RESUMO

Tomato chlorotic spot virus (TCSV) and groundnut ringspot virus (GRSV) share several genetic and biological traits. Both of them belong to the genus Tospovirus (family Peribunyaviridae), which is composed by viruses with tripartite RNA genome that infect plants and are transmitted by thrips (order Thysanoptera). Previous studies have suggested several reassortment events between these two viruses, and some speculated that they may share one of their genomic segments. To better understand the intimate evolutionary history of these two viruses, we sequenced the genomes of the first TCSV and GRSV isolates ever reported. Our analyses show that TCSV and GRSV isolates indeed share one of their genomic segments, suggesting that one of those viruses may have emerged upon a reassortment event. Based on a series of phylogenetic and nucleotide diversity analyses, we conclude that the parental genotype of the M segment of TCSV was either eliminated due to a reassortment with GRSV or it still remains to be identified.


Assuntos
Genoma Viral , Lycopersicon esculentum/virologia , Vírus Reordenados , Tospovirus/genética , Animais , Evolução Molecular , Variação Genética , Sequenciamento de Nucleotídeos em Larga Escala , Filogenia , RNA Viral/genética , Tisanópteros/virologia
17.
Virus Res ; 265: 10-19, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30831178

RESUMO

Tobacco curly shoot virus (TbCSV) is a monopartite DNA virus of the genus Begomovirus, which causes leaf curl symptoms in tobacco and tomato. The ß satellite of TbCSV (TbCSB induces more severe symptoms and enhanced virus accumulation when co-infects the host plants with TbCSV. Small interfering RNAs derived from virus(vsiRNAs) induce disease symptoms and promote virus invasion by target and guide the degradation of host transcripts The vsiRNAs derived from TbCSV and TbCSV + TbCSB remained to be explored to elucidate the molecular mechanism of symptoms development in plants. In the present work, two libraries of small RNA from TbCSV-infected and TbCSV + TbCSB-infected N. benthamiana plants were constructed and the vsiRNAs in both samples shared the same characteristics. The size of the vsiRNAs ranged from 18 to 30 nucleotides (nt), with most of them being 21 or 22 nt, which accounted for 29.11% and 23.22% in TbCSV plants and 29.39% and 21.82% in TbCSV + TbCSV plants, respectively. The vsiRNAs with A/U bias at the first site were abundant in both the TbCSV-treated and TbCSV + TbCSB-treated plants. It is discovered that the vsiRNAs continuously, but heterogeneously, distributed through bothe the TbCSV and TbCSB sequences. And the distribution profiles were similar in both the treatments such as mainly in the overlapping region of the AC2/AC3 coding sequences. The host transcripts targeted by vsiRNAs were predicted, and the targeted genes were found to be involved in varied biological processes. It is indicated that the presence of TbCSB does not significantly affect the production of vsiRNAs from TbCSV in plants, the distribution hotsopt of TbCSV vsiRNAs could be useful in designing effective targets for TbCSV resistance exploiting RNA interference.


Assuntos
Begomovirus/genética , Doenças das Plantas/virologia , RNA Interferente Pequeno/genética , Tabaco/virologia , Sequenciamento de Nucleotídeos em Larga Escala , Lycopersicon esculentum/virologia , Interferência de RNA , RNA Viral/genética
18.
Virus Genes ; 55(3): 356-367, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30924007

RESUMO

Bemisia tabaci (whitefly) is the sole vector of begomoviruses, which transmits them in a persistent and circulative manner from infected to healthy plants. During this process, begomoviruses interact with various proteins in the insect vector B. tabaci that would play a specific role in the virus transmission. Identification and characterization of such proteins are important to understand the complete process of virus transmission. Coat protein (CP) of begomoviruses is the only protein which is reported to interact with proteins of the insect vector B. tabaci. In this study, we performed yeast two-hybrid assay using CP of cotton leaf curl Rajasthan virus (CLCuV) and Tomato leaf curl New Delhi virus (ToLCNDV) as bait in separate experiments and cDNA prepared from total RNA of B. tabaci was used as prey. Yeast two-hybrid assay resulted in identification of a thioredoxin-like protein (TLP) from CLCuV yeast two-hybrid library. Later TLP was also found to interact with CP of ToLCNDV. In vitro pull-down assay showed TLP interaction with CP of both CLCuV and ToLCNDV. TLP was found to interact with ToLCNDV virus particles isolated from tomato leaves.


Assuntos
Begomovirus/genética , Lycopersicon esculentum/virologia , Doenças das Plantas/virologia , Tiorredoxinas/genética , Animais , Begomovirus/patogenicidade , Proteínas do Capsídeo/genética , Hemípteros/genética , Hemípteros/virologia , Interações Hospedeiro-Patógeno/genética , Índia , Insetos Vetores/genética , Lycopersicon esculentum/genética , Doenças das Plantas/genética
19.
Virol J ; 16(1): 36, 2019 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-30894176

RESUMO

BACKGROUND: Cross protection is a promising alternative to control plant viral diseases. One critical factor limiting the application of cross protection is the availability of attenuated mutants or mild strains. Potato virus X (PVX) infects many crops and induces huge economic losses to agricultural production. However, researches on the variability and mechanism of PVX virulence are scarce. METHODS: The mutants were obtained by introducing mutations into the RNA dependent RNA polymerase (RdRp) gene of PVX via site-directed mutagenesis. Attenuated mutants were screen according to their symptoms in Nicotiana benthamiana plants. The protection efficacy against severe infection were evaluated with interval of 5, 10 and 15 days. RESULTS: Among the 40 mutants obtained, four mutants carrying substitutions of either Glu46, Asn863, Asn968 or Glu1001 to Ala in PVX RdRp showed drastically attenuated symptom, accompanying with reduced accumulation levels of coat protein, plus- and minus-sense RNAs. When the interval between protective and challenging inoculations was 15 days, mutant E1001A (with substitution of Glu1001 to Ala in RdRp) provided complete protection against severe infection in both Nicotiana benthamiana and tomato, while E46A (Glu46 mutated to Ala) provided incomplete protection. To reduce the risk of reverse mutation, we constructed mutant dM which carries double mutations of both Glu46 and Glu1001 to Ala in RdRp. The mutant dM could provide effective protection against severe PVX infection. CONCLUSION: Mutations of Glu46, Asn863, Asn968 or Glu1001 to Ala in PVX RdRp significantly reduced the viral symptoms. Mutants E1001A and E46A could provide effective protection against wild type PVX in both Nicotiana benthamiana and tomato. These results provide theoretical and practical bases for the control of PVX via cross protection.


Assuntos
Proteção Cruzada , Mutação , Doenças das Plantas/virologia , Potexvirus/genética , China , Genoma Viral , Lycopersicon esculentum/virologia , Mutagênese Sítio-Dirigida , Folhas de Planta/virologia , Potexvirus/enzimologia , Potexvirus/fisiologia , RNA Replicase/genética , RNA Viral/genética , Genética Reversa , Tabaco/virologia , Proteínas Virais/genética , Virulência/genética
20.
Theor Appl Genet ; 132(5): 1543-1554, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30758531

RESUMO

KEY MESSAGE: Ty-6 is a major resistance gene on chromosome 10 of tomato that provides resistance against monopartite and bipartite begomoviruses and complements resistance conferred by the known Ty-3 and ty-5 genes. Resistance to monopartite and bipartite begomoviruses is an important breeding objective for cultivated tomato. Several begomovirus resistance genes have been introgressed from related Solanum species and are available for breeding purposes. In the present study, we mapped an additional locus, Ty-6, to chromosome 10 of tomato. Ty-6 is effective against both monopartite Tomato yellow leaf curl virus (TYLCV) and bipartite Tomato mottle virus (ToMoV). Gene action is incomplete dominance, with an intermediate resistance response when Ty-6 is heterozygous. Analysis of populations segregating for Ty-6 along with Ty-3 or ty-5 indicates that the highest level of resistance against TYLCV is attained when Ty-6 is combined with an additional resistance allele. Our results also demonstrate that ty-5 is ineffective against ToMoV. Although multiple SNPs linked to Ty-6 were identified and can be used for breeding purposes, none of these were consistently polymorphic between Ty-6 and ty-6 breeding lines. Further research is underway to generate resequencing data for several Ty-6 inbred lines for the discovery of additional sequence polymorphisms that can be used for fine mapping and characterizing the Ty-6 locus.


Assuntos
Cromossomos de Plantas , Resistência à Doença/genética , Genes de Plantas , Lycopersicon esculentum/genética , Doenças das Plantas/virologia , Begomovirus , Mapeamento Cromossômico , Lycopersicon esculentum/virologia , Doenças das Plantas/genética , Locos de Características Quantitativas
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