scholarly journals V2 of tomato yellow leaf curl virus can suppress methylation-mediated transcriptional gene silencing in plants

2014 ◽  
Vol 95 (1) ◽  
pp. 225-230 ◽  
Author(s):  
Bi Wang ◽  
Fangfang Li ◽  
Changjun Huang ◽  
Xiuling Yang ◽  
Yajuan Qian ◽  
...  

Tomato yellow leaf curl virus (TYLCV) is a DNA virus belonging to the genus Begomovirus. TYLCV replicates using double-stranded DNA intermediates that can become the target of plant transcriptional gene silencing (TGS). Here, we show that the V2 protein of TYLCV can suppress TGS of a transcriptionally silenced green fluorescent protein (GFP) transgene in Nicotiana benthamiana line 16-TGS. Through bisulfite sequencing and chop-PCR, we demonstrated that the TYLCV V2 can reverse GFP transgene silencing by reducing the methylation levels in the 35S promoter sequence. Both AtSN1 and MEA-ISR loci in Arabidopsis thaliana were previously reported to be strongly methylated, and we show that the methylation status of both loci was significantly reduced in TYLCV V2 transgenic Arabidopsis plants. We conclude that TYLCV can efficiently suppress TGS when it infects plants, and its V2 protein is responsible for the TGS suppression activity.

2021 ◽  
Vol 12 ◽  
Author(s):  
Corien M. Voorburg ◽  
Yuling Bai ◽  
Richard Kormelink

Ty-1 presents an atypical dominant resistance gene that codes for an RNA-dependent RNA polymerase (RDR) of the gamma class and confers resistance to tomato yellow leaf curl virus (TYLCV) and other geminiviruses. Tomato lines bearing Ty-1 not only produce relatively higher amounts of viral small interfering (vsi)RNAs, but viral DNA also exhibits a higher amount of cytosine methylation. Whether Ty-1 specifically enhances posttranscriptional gene silencing (PTGS), leading to a degradation of RNA target molecules and primarily relying on 21–22 nucleotides (nts) siRNAs, and/or transcriptional gene silencing (TGS), leading to the methylation of cytosines within DNA target sequences and relying on 24-nts siRNAs, was unknown. In this study, small RNAs were isolated from systemically TYLCV-infected leaves of Ty-1 encoding tomato plants and susceptible tomato Moneymaker (MM) and sequence analyzed. While in susceptible tomato plants vsiRNAs of the 21-nt size class were predominant, their amount was drastically reduced in tomato containing Ty-1. The latter, instead, revealed elevated levels of vsiRNAs of the 22- and 24-nt size classes. In addition, the genomic distribution profiles of the vsiRNAs were changed in Ty-1 plants compared with those from susceptible MM. In MM three clear hotspots were seen, but these were less pronounced in Ty-1 plants, likely due to enhanced transitive silencing to neighboring viral genomic sequences. The largest increase in the amount of vsiRNAs was observed in the intergenic region and the V1 viral gene. The results suggest that Ty-1 enhances an antiviral TGS response. Whether the elevated levels of 22 nts vsiRNAs contribute to an enhanced PTGS response or an additional TGS response involving a noncanonical pathway of RNA dependent DNA methylation remains to be investigated.


2012 ◽  
Vol 25 (10) ◽  
pp. 1294-1306 ◽  
Author(s):  
Ana P. Luna ◽  
Gabriel Morilla ◽  
Olivier Voinnet ◽  
Eduardo R. Bejarano

Tomato yellow leaf curl disease (TYLCD) is caused by a complex of phylogenetically related Begomovirus spp. that produce similar symptoms when they infect tomato plants but have different host ranges. In this work, we have evaluated the gene-silencing-suppression activity of C2, C4, and V2 viral proteins isolated from the four main TYLCD-causing strains in Spain in Nicotiana benthamiana. We observed varying degrees of local silencing suppression for each viral protein tested, with V2 proteins from all four viruses exhibiting the strongest suppression activity. None of the suppressors were able to avoid the spread of the systemic silencing, although most produced a delay. In order to test the silencing-suppression activity of Tomato yellow leaf curl virus (TYLCV) and Tomato yellow leaf curl Sardinia virus (TYLCSV) proteins in a shared (tomato) and nonshared (bean) host, we established novel patch assays. Using these tools, we found that viral proteins from TYLCV were able to suppress silencing in both hosts, whereas TYLCSV proteins were only effective in tomato. This is the first time that viral suppressors from a complex of disease-causing geminiviruses have been subject to a comprehensive analysis using two economically important crop hosts, as well as the established N. benthamiana plant model.


2018 ◽  
Vol 92 (18) ◽  
Author(s):  
Bi Wang ◽  
Xiuling Yang ◽  
Yaqin Wang ◽  
Yan Xie ◽  
Xueping Zhou

ABSTRACT Cytosine DNA methylation is a conserved epigenetic silencing mechanism that defends against biotic stresses such as geminivirus infection. As a countermeasure, geminiviruses encode proteins that inhibit methylation and transcriptional gene silencing (TGS). Previous studies showed that V2 protein of Tomato yellow leaf curl virus (TYLCV) functions as a TGS suppressor. However, how V2 mediates TGS suppression remains unknown. Here we show that V2 interacts directly with a Nicotiana benthamiana histone deacetylase 6 (NbHDA6), a homolog of Arabidopsis HDA6 (AtHDA6), known to be involved in gene silencing in cooperation with methyltransferase 1 (MET1). NbHDA6 genetically complemented a late-flowering phenotype and restored histone deacetylation of an AtHDA6 mutant. Furthermore, our investigation showed that NbHDA6 displayed histone deacetylase enzymatic activity, which was not inhibited by V2. Genetic analysis revealed that silencing of NbHDA6 expression resulted in enhanced susceptibility to TYLCV infection. In addition, methylation-sensitive PCR and bisulfite sequencing analysis showed that silencing of NbHDA6 expression caused reduced DNA methylation of the viral genome in infected plants. HDA6 was previously shown to recruit and physically interact with MET1 to function in gene silencing. Using competitive pulldown and coimmunoprecipitation assays, we demonstrated that V2 did not interact but competed with NbMET1 for direct binding to NbHDA6. These findings suggest that V2 interacts with host HDA6 and interferes with the recruitment of MET1 by HDA6, resulting in decreased methylation of the viral DNA genome by TGS with a concomitant increase in host susceptibility to TYLCV infection. IMPORTANCE Plants employ repressive viral genome methylation as an epigenetic defense against geminiviruses. In turn, geminiviruses encode proteins that inhibit methylation by TGS. Previous studies showed that TYLCV V2 can efficiently suppress TGS, but the mechanism remains unknown. We showed that V2 interacted with NbHDA6 but did not inhibit its enzymatic activity. As HDA6 is known to be involved in gene silencing in cooperation with MET1, we explored the relationship between V2, NbMET1, and NbHDA6. Our investigation showed that V2 did not interact but competed with NbMET1 for direct binding to NbHDA6. To our knowledge, this is the first report that viral proteins inhibit TGS by interacting with histone deacetylase but not by blocking the methyl cycle. This work provides an additional mechanism for TGS suppression by geminiviruses.


2001 ◽  
Vol 14 (9) ◽  
pp. 1125-1128 ◽  
Author(s):  
Rene van Wezel ◽  
Huangting Liu ◽  
Po Tien ◽  
John Stanley ◽  
Yiguo Hong

Expression of the Tomato yellow leaf curl virus-China (TYLCV-C) C2 protein and green fluorescent protein (GFP) fused to the C2 protein (C2-GFP) in Nicotiana benthamiana from a Potato virus X (PVX) vector induced necrotic ringspots on inoculated leaves as well as necrotic vein banding and severe necrosis on systemically infected leaves. The localization of GFP fluorescence in plant cells infected with PVX/C2-GFP and in insect cells transfected with Baculovirus expressing C2-GFP indicates that the TYLCV-C C2 protein is capable of shuttling GFP into plant and insect cell nuclei. Our data demonstrate that the TYLCV-C C2 protein may contribute to viral pathogenicity in planta and is nuclear localized.


1997 ◽  
Vol 10 (5) ◽  
pp. 571-579 ◽  
Author(s):  
A. Brunetti ◽  
M. Tavazza ◽  
E. Noris ◽  
R. Tavazza ◽  
P. Caciagli ◽  
...  

A truncated version of the C1 gene of tomato yellow leaf curl geminivirus (TYLCV), encoding the first 210 amino acids of the multifunctional Rep protein, was introduced by Agrobacterium transformation into Lycopersicon esculentum cv. Moneymaker plants under the transcriptional control of an enhanced cauliflower mosaic virus 35S promoter. One R0 plant (line 47) carrying the C1 gene in two loci (A and B) and accumulating the truncated Rep protein (T-Rep), was crossed with either a wild-type plant, or a C1 antisense plant (line 10). The wild type (wt) × 47 progeny were phenotypically homogeneous, contained either A or B locus, expressed high levels of T-Rep protein, had a “curled” phenotype, and were resistant to TYLCV when challenged either by agroinfection or by the vector Bemisia tabaci. In the 10 × 47 progeny, plants carrying only the sense gene behaved like the wt × 47 progeny, while those containing both sense and antisense transgenes did not accumulate the T-Rep protein, showed a normal phenotype, and were not resistant, showing that accumulation of T-Rep protein is required to confer TYLCV resistance. Plants accumulating T-Rep were susceptible to a distinct geminivirus, tomato leaf curl virus (ToLCV-Au).


EPPO Bulletin ◽  
2002 ◽  
Vol 32 (1) ◽  
pp. 31-35
Author(s):  
A. F. Arsenio ◽  
E. Neto ◽  
N. Ramos ◽  
S. Mangerico ◽  
E. Fortunato ◽  
...  

2020 ◽  
pp. 30-34
Author(s):  
С.Ф. Гавриш ◽  
Т.А. Редичкина ◽  
А.В. Буц ◽  
Г.М. Артемьева

Дана информация об изучении коллекции гибридов F1томата (Solanum lycopersicum L.) зарубежной селекции различных фирм-оригинаторов, рекомендованных производителями семян как толерантные к вирусу желтой курчавости листьев томата. Все гибриды обладали комплексом хозяйственно ценных признаков и набором генов устойчивости к основным заболеваниям томата, в том числе к новому для юга России опасному патогену с максимальным потенциальным риском – вирусу желтой курчавости листьев томата (Tomato yellow leaf curl virus — TYLCV). Исследования проведены в 2017-2018 годах в лаборатории пасленовых культур ООО «НИИСОК» и в лаборатории молекулярной диагностики растений ООО «Семеновод». Всего было протестировано 34 гибрида F1 томата. Гибриды оценивали по совокупности хозяйственно ценных признаков, также проводили молекулярно-генетический анализ на наличие и аллельное состояние основных генов устойчивости: к вирусу табачной мозаики (Tm2а), фузариозному увяданию (I2), вертициллезному увяданию (Ve), к кладоспориозу (Cf9), нематодам (Mi1.2), вирусу бронзовости томата (Sw5), вирусу желтой курчавости листьев томата (Ty3a). Установлено, что все проанализированные гибриды томата с заявленной оригинаторами семян устойчивостью к вирусу желтой курчавости листьев были гетерозиготны по гену Ty3a. На основании проведенных исследований и с учетом требований рынка разработаны модели гибридов F1 томата юга России. Перспективный гибрид томата должен обладать индетерминантным типом роста с укороченными междоузлиями (4,5-5 см) а также хорошей облиственностью. Плоды томата должны быть с красной равномерной окраской без зеленого пятна у плодоножки, с плоскоокруглой или округлой формой плода и со средней массой 220-270 г. Для повышения транспортабельности томатов необходимо, чтобы плоды отличались высокой прочностью и характеризовались хорошей лежкостью. Урожайность гибрида томата должна быть более 30 кг/м2, а товарность - не менее 85%. Гибрид томата должен обладать следующим набором генов устойчивости в гетерозиготном состоянии: Ty3a, Mi1.2, Cf-9, а также в гомозиготном состоянии: Tm2a, I2, Ve. The article provides information on the study of the collection of F1 tomato hybrids (Solanum lycopersicumL.) of foreign breeding from various firms-originators recommended for cultivation in regions with a strong spread of tomato yellow leaf curl virus. All hybrids had a complex of economically valuable traits and a set of genes for resistance to the main diseases of tomato, including a new dangerous pathogen for the South of Russia with a maximum potential risk — the tomato yellow leaf curl virus (TYLCV). The studies were carried out in 2017-2018 in the Solanaceae Laboratory of LLC NIISOK and in the Molecular Diagnostics Laboratory of Plants of LLC Semenovod. A total of 34 F1 tomato hybrids were tested. The hybrids were assessed by a set of economically valuable traits. Molecular genetic analysis was also carried out for the presence and allelic state of the main resistance genes: Tomato mosaic virus (Tm2a), Fusarium wilt (I2), Werticillium wilt (Ve), Cladosporium fulvum (Cf9), Nematodes (Mi1.2), Tomato spotted wilt virus (Sw5), Tomato yellow leaf curl virus (Ty3a). It was found that all the analyzed tomato hybrids with the declared by seed originators resistance to yellow leaf curl virus were heterozygous for the Ty3a gene. Based on the conducted research and taking into account the market requirements, models of F1 tomato hybrids for protected ground for the South of Russia have been developed. A promising tomato hybrid should have an indeterminate growth type with shortened internodes (4.5-5 cm) and good foliage. Tomato fruits should have a uniform red color without green shoulders, with a flat-round or round shape of the fruit and with an average weight of 220-270 g. To increase the transportability of tomatoes, it is necessary that the fruits are highly firm and characterized by good shelf life. The yield of tomato hybrid should be more than 30 kg/m2, and marketability should be at least 85%. The tomato hybrid should have the following set of resistance genes in a heterozygous state: Ty3a, Mi1.2, Cf-9, and also in a homozygous state: Tm2a, I2, Ve.


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