scholarly journals Sequence Analysis and Classification of Apparent Recombinant Begomoviruses Infecting Tomato in the Nile and Mediterranean Basins

2005 ◽  
Vol 95 (5) ◽  
pp. 549-555 ◽  
Author(s):  
C. M. Fauquet ◽  
S. Sawyer ◽  
A. M. Idris ◽  
J. K. Brown

Numerous whitefly-transmitted viral diseases of tomato have emerged in countries around the Nile and Mediterranean Basins the last 20 years. These diseases are caused by monopartite geminiviruses (family Gemini viridae) belonging to the genus Begomovirus that probably resulted from numerous recombination events. The molecular biodiversity of these viruses was investigated to better appreciate the role and importance of recombination and to better clarify the phylogenetic relationships and classification of these viruses. The analysis partitioned the tomato-infecting begomoviruses from this region into two major clades, Tomato yellow leaf curl virus and Tomato yellow leaf curl Sardinia virus. Phylogenetic and pairwise analyses together with an evaluation for gene conversion were performed from which taxonomic classification and virus biodiversity conclusions were drawn. Six recombination hotspots and three homogeneous zones within the genome were identified among the tomatoinfecting isolates and species examined here, suggesting that the recombination events identified were not random occurrences.

Plant Disease ◽  
2000 ◽  
Vol 84 (7) ◽  
pp. 810-810 ◽  
Author(s):  
G. Pietersen ◽  
A. M. Idris ◽  
K. Krüger ◽  
J. K. Brown

Tomato yellow leaf curl virus (TYLCV) causes a serious disease of tomato in many countries throughout the world. Preliminary reports suggested that TYLC disease was present in 1997 in South Africa. In 1998 140 ha of tomato fields in the Onderberg area were assessed for possible presence of TYLCV. Symptoms like those caused by TYLCV isolates in Israel were observed in most fields, and disease incidence ranged from <1 to 50%. Yield losses in individual plants ranged from negligible to 100% and appeared related to the age of the plants at time of infection. Two isolates of the suspect virus were experimentally transmitted from symptomatic tomato to virus-free, glasshouse-grown tomato seedlings by colony. Field and colony whiteflies were identified as the Bemisia tabaci based on mt COI sequence analysis (1). Attempts to transmit the suspect begomovirus by sap inoculation between tomato plants were unsuccessful. Polymerase chain reaction (PCR) amplification with degenerate PCR primers (2) that permit detection of the coat protein gene (AV1) and the common region (CR) of other begomoviruses yielded an amplicon of the expected size (2,100 bp), suggesting begomovirus association with diseased tomato plants. Nucleotide (nt) sequence analysis of AV1 for both tomato isolate AF261885 indicated that they were indistinguishable and shared less than 78% sequence identity with other well-studied begomoviruses, indicating a distinct, previously undescribed begomovirus species. AV1 sequence comparisons also revealed that its closest relatives were members of the TYLCV cluster, which includes South African cassava mosaic virus (77.4%) (AF11785), East African cassava mosaic virus (77.3%) (AJ006459), and TYLCV-IS (76.2%) (X15656). The theoretical Rep binding element in the CR, TCGGT, was identical to TYLCV-IS and Cotton leaf curl virus-Pakistan (AJ002448) (AJ002449). Here, we provisionally designate this new tomato-infecting begomoviral species, Tomato curly stunt virus from South Africa (ToCSV-SA). References: (1) D. R. Frohlich et al. Mol. Ecol. 8:1683, 1999. (2) A. M. Idris and J. K. Brown. Phytopathology 88:648, 1998.


Plant Disease ◽  
2007 ◽  
Vol 91 (8) ◽  
pp. 1056-1056 ◽  
Author(s):  
M. R. Rojas ◽  
T. Kon ◽  
E. T. Natwick ◽  
J. E. Polston ◽  
F. Akad ◽  
...  

Tomato yellow leaf curl disease caused by the whitefly-transmitted begomovirus (genus Begomovirus, family Geminiviridae) Tomato yellow leaf curl virus (TYLCV) is one of the most damaging diseases of tomato. TYLCV was introduced into the New World in the early 1990s and by the late 1990s, it was found in Florida (2). In 2005 and 2006, the virus was reported from northern Mexico (states of Sinaloa and Tamaulipas) (1) and subsequently from Texas and Arizona. In March 2007, tomato (Lycopersicon esculentum) plants growing in a greenhouse in Brawley, CA showed TYLCV-like symptoms including stunted upright growth, shortened internodes, and small upcurled leaves with crumpling and strong interveinal and marginal chlorosis. These plants also sustained high populations of whiteflies. Symptomatic tomato leaves and associated whiteflies were collected from inside the greenhouse. Leaf samples also were collected from symptomless weeds (cheeseweed [Malva parviflora] and dandelion [Taraxacum officinale]) outside of the greenhouse. Total nucleic acids were extracted from 41 symptomatic tomato leaf samples, seven samples of adult whiteflies (approximately 50 per sample), and six leaf samples each from cheeseweed and dandelion. PCR analyses were performed with the degenerate begomovirus primers PAL1v1978 and PAR1c496 (3) and a TYLCV capsid protein (CP) primer pair (4). The expected size of approximately 1.4-kbp and 300-bp DNA fragments, respectively, were amplified from extracts of all 41 symptomatic tomato leaves and adult whitefly samples; whereas the 300-bp DNA fragment was amplified from all six cheeseweed samples and four of the six dandelion samples. Sequence analysis of a portion of the AC1/C1 gene from the approximately 1.4-kbp fragment amplified from 12 tomato leaf samples and four whiteflies samples revealed 99 to 100% identity with the homologous sequence of TYLCV from Israel (GenBank Accession No. X15656). The putative genome of the California TYLCV isolate was amplified using PCR and an overlapping primer pair (TYBamHIv: 5′-GGATCCACTTCTAAATGAATTTCCTG-3′ and TYBamHI2c: 5′-GGATCCCACATAGTGCAAGACAAAC-3′), cloned and sequenced. The viral genome was 2,781 nt (GenBank Accession No. EF539831), and sequence analysis confirmed it was a bona fide isolate of TYLCV. The California TYLCV sequence is virtually identical (99.7% total nucleotide and 100% CP amino acid sequence identity) to a TYLCV isolate from Sinaloa, Mexico (GenBank Accession No. EF523478) and closely related to isolates from China (AM282874), Cuba (AJ223505), Dominican Republic (AF024715), Egypt (AY594174), Florida (AY530931), Japan (AB192966), and Mexico (DQ631892) (sequence identities of 98.2 to 99.7%). Together, these results establish that TYLCV was introduced to California, probably from Mexico. Because the tomatoes in this greenhouse were grown from seed, and symptoms did not appear until after initial fruit set, the virus was probably introduced via viruliferous whiteflies. To our knowledge, this is the first report of TYLCV infecting tomato plants in California. References: (1) J. K. Brown and A. M. Idris. Plant Dis. 90:1360, 2006. (2) J. E. Polston et al. Plant Dis. 83:984, 1999. (3) M. R. Rojas et al. Plant Dis. 77:340, 1993. (4) R. Salati et al. Phytopathology 92:487, 2002.


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.


2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Adi Moshe ◽  
Eduard Belausov ◽  
Annette Niehl ◽  
Manfred Heinlein ◽  
Henryk Czosnek ◽  
...  

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Nathalie Becker ◽  
Loup Rimbaud ◽  
Frédéric Chiroleu ◽  
Bernard Reynaud ◽  
Gaël Thébaud ◽  
...  

2014 ◽  
Vol 165 (4) ◽  
pp. 1684-1697 ◽  
Author(s):  
Dagan Sade ◽  
Nir Sade ◽  
Oz Shriki ◽  
Stephen Lerner ◽  
Alem Gebremedhin ◽  
...  

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