Whitefly HES1 binds to the intergenic region of Tomato yellow leaf curl China virus and promotes viral gene transcription

AbstractA yellow leaf curl disease with chlorotic and yellowish leaves, upward leaf curling and stunting symptoms was observed on tomato in Shantou city of Guangdong province. A virus isolate BS was obtained from a diseased tomato plant. The complete DNA-A sequence of the virus isolate BS was determined to be 2740 nucleotides long, with all the characteristic features of begomovirus genome organization. BS DNA-A encoded six potential open reading frames (ORFs), with two (AV1 and AV2) in virus sense and four (AC1, AC2, AC3 and AC4) in complementary sense, and contained an intergenic region of 269 nucleotides. The results of BLAST searches showed that BS DNA-A had higher sequence identity with reported begomoviruses in Asia than with those in America and Africa. Further sequence comparisons indicated that BS was most closely related to the isolate of Tomato leaf curl Taiwan virus (ToLCTWV-[Taiwan]) with a sequence identity of 97.7%. Nucleotide sequence identities of AV1, AV2, AC1, AC2, AC3, AC4 and intergenic region (IR) between BS and ToLCTWV-[Taiwan] were 98.6, 98.0, 98.0, 97.5, 96.3, 98.6 and 96.6%, respectively, while that of the six ORF-encoded proteins between BS and ToLCTWV-[Taiwan] were 97.7, 99.1, 97.5, 95.6, 91.8 and 99.0%, respectively. Phylogenetic analysis based on the DNA-A sequences has also indicated that BS is most closely related to ToLCTWV-[Taiwan], forming a branch with ToLCTWV-[Taiwan], Tomato leaf curl Guangdong virus and Tomato yellow leaf curl Guangdong virus. The above results demonstrate that BS is an isolate of ToLCTWV.

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Presence of Tomato yellow leaf curl virus Infecting Squash (Curcubita pepo) in Cuba

Plant Disease ◽

10.1094/pdis.2004.88.5.572c ◽

2004 ◽

Vol 88 (5) ◽

pp. 572-572 ◽

Cited By ~ 14

Author(s):

Y. Martinez Zubiaur ◽

D. Fonseca ◽

M. Quiñones ◽

I. Palenzuela

Keyword(s):

Intergenic Region ◽

Tomato Yellow Leaf ◽

Yellow Leaf ◽

Degenerate Primers ◽

Specific Primers ◽

Cycle Sequencing ◽

Pcr Product ◽

Three Samples ◽

Leaf Curl Virus ◽

Leaf Curl

In a survey conducted in Havana Province during January and February 2003, symptoms of curling and light yellowing of leaves were found in squash plants (Curcubita pepo). DNA from leaves of six symptomatic squash plants was extracted (1) and hybridized at high stringency with specific probes of the intergenic region of Tomato yellow leaf curl virus (TYLCV, genus begomovirus) isolated in Cuba by using a nonradioactive hybridization kit (AlkPhos Direct Labeling and Detection Systems; Amersham Pharmacia Biotech Inc., Piscataway, NJ). Three samples were positive in the nonradioactive analyses. The same samples were positive using polymerase chain reaction (PCR) when the DNA was analyzed with degenerate primers PAL1v1978/PAR1c715 for DNA-A (5), specific primers, ORITY1/ORITY2, for the intergenic region (2), and overlapping specific primers for TYLCV (3). Fragments of 1.4, 0.750, and 2.8 kb were cloned using pGem-T Easy (Promega, Madison, WI), and the six clones obtained were sequenced using the Terminator Cycle Sequencing Kit in a SEQ 4 × 4 machine (Amersham Pharmacia Biotech Inc.). Sequences of three fragments exhibited 95 to 97% homology with TYLCV (GenBank Accession Nos. AF414089 and AF260331). Additionally, we did not obtain a PCR product when DNA was amplified using degenerate primers PBV1c800/PBC1v2039 for DNA-B (4). These results suggest that TYLCV is present in squash in field plantations, and these plants may serve as a virus reservoir for other crops such a tomatoes. References: (1) S. L. Dellaporta et al. Plant. Mol. Biol. Rep. 1(4):19, 1983. (2) Y. Martínez et al. Rev. Prot. Veg. 18(3):168, 2003. (3) M. K. Nakhla et al. Plant Dis. 78:926, 1994. (4) M. Rojas et al. Plant Dis. 77:340, 1993.

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Small RNA Profiling of Susceptible and Resistant Ty-1 Encoding Tomato Plants Upon Tomato Yellow Leaf Curl Virus Infection

Frontiers in Plant Science ◽

10.3389/fpls.2021.757165 ◽

2021 ◽

Vol 12 ◽

Author(s):

Corien M. Voorburg ◽

Yuling Bai ◽

Richard Kormelink

Keyword(s):

Gene Silencing ◽

Cytosine Methylation ◽

Tomato Yellow Leaf ◽

Transcriptional Gene Silencing ◽

Viral Gene ◽

Yellow Leaf ◽

Tomato Plants ◽

Susceptible Tomato ◽

Leaf Curl Virus ◽

Leaf Curl

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.

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Control of the Bemisia tabaci/Tomato yellow leaf curl virus complex on protected tomato crops in Algarve (Portugal)*

EPPO Bulletin ◽

10.1046/j.1365-2338.2002.00558.x ◽

2002 ◽

Vol 32 (1) ◽

pp. 31-35

Author(s):

A. F. Arsenio ◽

E. Neto ◽

N. Ramos ◽

S. Mangerico ◽

E. Fortunato ◽

...

Keyword(s):

Bemisia Tabaci ◽

Tomato Yellow Leaf ◽

Yellow Leaf ◽

Virus Complex ◽

Leaf Curl Virus ◽

Leaf Curl

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Study of a collection of tomato hybrids with genetic resistance to the yellow leaf curl virus in Southern Russia

Kartofel` i ovoshi ◽

10.25630/pav.2020.32.41.007 ◽

2020 ◽

pp. 30-34

Author(s):

С.Ф. Гавриш ◽

Т.А. Редичкина ◽

А.В. Буц ◽

Г.М. Артемьева

Keyword(s):

Resistance Genes ◽

Molecular Genetic Analysis ◽

Tomato Yellow Leaf ◽

Tomato Mosaic Virus ◽

Average Weight ◽

Yellow Leaf ◽

The South ◽

Economically Valuable Traits ◽

Leaf Curl Virus ◽

Leaf Curl

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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MOLECULAR IDENTIFICATION OF TOMATO GERMPLASM FOR RESISTANCE TO TOMATO YELLOW LEAF CURL VIRUS IN EGYPT

Journal of Productivity and Development ◽

10.21608/jpd.2014.42656 ◽

2014 ◽

Vol 19 (3) ◽

pp. 373-380

Keyword(s):

Molecular Identification ◽

Tomato Yellow Leaf ◽

Yellow Leaf ◽

Leaf Curl Virus ◽

Leaf Curl

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Strategies to Inhibit Hepatitis B Virus at the Transcript Level

Viruses ◽

10.3390/v13071327 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1327

Author(s):

Bingqian Qu ◽

Richard J. P. Brown

Keyword(s):

Hepatitis B Virus ◽

Hepatitis B ◽

Gene Transcription ◽

Antigen Expression ◽

Transcript Level ◽

Viral Gene ◽

Small Interfering Rnas ◽

Viral Gene Transcription ◽

Hbv Vaccination ◽

B Virus

Approximately 240 million people are chronically infected with hepatitis B virus (HBV), despite four decades of effective HBV vaccination. During chronic infection, HBV forms two distinct templates responsible for viral transcription: (1) episomal covalently closed circular (ccc)DNA and (2) host genome-integrated viral templates. Multiple ubiquitous and liver-specific transcription factors are recruited onto these templates and modulate viral gene transcription. This review details the latest developments in antivirals that inhibit HBV gene transcription or destabilize viral transcripts. Notably, nuclear receptor agonists exhibit potent inhibition of viral gene transcription from cccDNA. Small molecule inhibitors repress HBV X protein-mediated transcription from cccDNA, while small interfering RNAs and single-stranded oligonucleotides result in transcript degradation from both cccDNA and integrated templates. These antivirals mediate their effects by reducing viral transcripts abundance, some leading to a loss of surface antigen expression, and they can potentially be added to the arsenal of drugs with demonstrable anti-HBV activity. Thus, these candidates deserve special attention for future repurposing or further development as anti-HBV therapeutics.

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