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Herbaceous plant hosts are essential to grapevine virus research. Such plants offer numerous advantages as experimental hosts of viruses over Vitis species, the natural hosts. They grow faster, have a shorter generation time, and require little maintenance in the greenhouse or growth chamber in comparison with the natural hosts for which experiments are more technically challenging and last substantially longer. Local, pseudo-local, systemic, and pseudo-systemic herbaceous plants have been identified among infected experimental hosts and used for advances in grapevine virology. The discovery pipeline made possible by alternative model hosts has had a tremendous impact on the field. Species of Chenopodium, Nicotiana, Phaseolus, Cucumis, Petunia, and Cuscuta have served to document mechanical or graft transmission of grapevine viruses, fulfill Koch's postulates, study pathogenesis, examine movement, determine replication, purify and observe virus particles, image virions at the atomic level, develop diagnostic assays, characterize vector-mediated transmission, assess defense and counter defense mechanisms, and engineer resistance, among many other critical milestones. Alternative hosts continue to have intrinsic value for discoveries, although many technologies, including high-throughput sequencing, have largely outperformed their use for diagnostic applications. This review focuses on the critical role of herbaceous plant hosts in important discoveries on the biology of grapevine viruses. [ABSTRACT FROM AUTHOR]

This article reports the first occurrence of the eggplant mottled dwarf virus (EMDV) in Pittosporum tobria plants in the United Kingdom. The virus was discovered during routine plant health inspections in two nurseries in West Sussex and Gloucestershire. Symptoms of the virus included chlorotic mottling of veins and distortion of leaves. The presence of EMDV was confirmed through high throughput sequencing and ELISA testing. The virus is known to be transmitted by the leafhopper Anaceratogallia ribauti, which is present in the UK, raising concerns about its potential spread. The impact of EMDV on vegetable crops is currently minor due to its low incidence in the field. The study was funded by the Defra-Fera long term services agreements. [Extracted from the article]

Tospoviruses, an emerging group of plant viruses, infect food crops and ornamental plants causing billions of dollars in losses worldwide. There are at least 28 Tospovirus species worldwide, most of which are found in tropical and subtropical environments. Despite having a largely tropical climate, Africa has only five reported species namely: Tomato spotted wilt virus (TSWV), Groundnut ringspot virus (GRSV), Impatiens necrotic spot virus (INSV), Tomato yellow ring virus (TYRV) and Iris yellow spot virus (IYSV). The low tospovirus diversity on the continent is mainly due to lack of surveys. Most Tospovirus species have only been reported in the last twenty-five years, yet no surveys have been done in most African countries. Most African countries lack institutional and infrastructural capacities to carry out virology research. This article reviews the characteristics and control of tospoviruses, with a bias towards those found in Africa. [ABSTRACT FROM AUTHOR]

Cucurbit crops are cultivated throughout the world. Melon (Cucumis melo L.), cucumber (Cucumis sativus L.), watermelon (Citrullus lanatus (Thumb.) Mat. et Nak.), squash and pumpkin (Cucurbita spp.) are the major crops. In Latin America and the Caribbean islands (LAC) cucurbits are consumed as a part of the daily diet since pre-Columbian times, when some species such as Cucurbita pepo L., Cucurbita moschata Duch. and Cucurbita maxima Duch. were domesticated by American Indians. In LAC, cucurbit crops have become export commodities and a source of income for several countries, in addition to their role in local consumption. The increase of area devoted to cucurbit crops and the intensification of production has led to the emergence of severe viral epidemics that threaten the sustainability of these cultures. This paper reviews the cucurbit viruses described in the region and their impact. In addition, the potential of different measures to control the most frequent cucurbit viruses in LAC is discussed. [ABSTRACT FROM AUTHOR]

The article offers information on the nepovirus Grapevine fanleaf virus (GFLV), a virus that causes degenerative disease on grapevines. Topics include the two main symptoms of fanleaf namely infectious malformations and yellow mosaic, the cytopathology of GFLV, and its transmission. Information on varietal susceptibility, detection and control is also provided.

The presence and distribution of Tomato spotted wilt virus (TSWV) on different vegetable, ornamental, tobacco plants and weeds was investigated in the open field and greenhouses in different locations of Montenegro. DAS ELISA was used to identify the virus in 2072 samples collected from 2007 to 2009. TSWV was detected in two samples collected in 2007, none of the samples collected in 2008 and 50 samples collected in 2009. The sensitivity and specificity of four different previously described primer sets for TSWV detection were assessed by RT-PCR. The N gene sequences were compared with those of 20 new isolates from Montenegro, Serbia, Italy and Brazil and 27 others retrieved from the NCBI database. Nucleotide sequences comparison revealed high level of similarity (97-99,9%) between Montenegrin and TSWV isolates from other European countries. Phylogenetic analysis of the N gene revealed seven distinct subgroups, showing that the investigated isolates clustered with those from the same geographic region, with the exception of one Montenegrin (Is-103) and one Italian isolate (Gb-21). [ABSTRACT FROM AUTHOR]

Kiwifruit (Actinidia deliciosa) was introduced to New Zealand more than one hundred years ago and the New Zealand-raised cv. Hayward is now the dominant cultivar grown worldwide. Further accessions of kiwifruit seed and scionwood have been sourced from China for research and breeding. In one importation consignment, the first virus naturally infecting kiwifruit, Apple stem grooving virus (ASGV), was identified following symptoms observed in quarantined plants (2003). Since that time a further 12 viruses have been identified in kiwifruit. We classify these 13 viruses into three groups. The first group comprises the non-specialist viruses and includes Alfalfa mosaic virus (AMV) and Cucumber mosaic virus (CMV) both members of the family Bromoviridae. The group also includes a further five viruses that appear to have limited effect on kiwifruit: two tobamoviruses, Ribgrass mosaic virus (RMV) and Turnip vein clearing virus (TVCV); a tombusvirus, Cucumber necrosis virus (CNV); a novel potexvirus; and Apple stem gooving virus (ASGV, genus Capillovirus). Most of the viruses classified in this first group are cosmopolitan and sometimes orchard weeds provide reservoirs for infection. The second group comprises the kiwifruit-adapted viruses. This group includes three novel viruses. i.e. two vitiviruses, Actinidia virus A (AcVA) and Actinidia virus B (AcVB), and a citrivirus closely related to Citrus leaf blotch virus (CLBV). In addition, preliminary evidence of a novel virus belonging to the Closteroviridae family has been obtained. The third group of viruses induces disease in kiwifruit. To date only two viruses have caused significant damage to kiwifruit within commercial orchards. In New Zealand, Cherry leaf roll virus (CLRV) has been detected on kiwifruit associated with symptoms including leaf spots, fruit malformation, reduction in yield, bark cracking and cane wilting. Pelargonium zonate spot virus (PZSV) has been detected in Italy associated with severe symptoms on leaves and fruit. [ABSTRACT FROM AUTHOR]

Tomato spotted wilt virus (TSWV) was isolated from naturally infected lettuce grown in Jordan. This virus isolate (TSWV-J) was identified based on transmission studies, host range reaction, and serological tests. RT-PCR was used for the detection of TSWV in infected plant tissues. Total RNA isolated from infected lettuce plants was subjected to RT-PCR using primers specific to the nucleocapsid (N) gene of TSWV and the amplified 620 bp product was cloned and sequenced. Nucleotide sequence and phylogenetic analysis of the RTPCR amplicon confirmed the Jordanian virus as an isolate of TSWV. Furthermore, the genetic diversity of TSWV in Jordan was investigated. The TSWV isolates shared high nucleotide sequence identity (93-99%) with those from other countries. To our knowledge, this is the first report of TSWV infection on lettuce in Jordan. [ABSTRACT FROM AUTHOR]

Over a period of two years, more than 5,000 citrus trees were tested for the presence of Citrus tristeza virus (CTV) on the island of Crete, resulting in thirty eight positives. Comparisons of the relative transcript levels of CTV p23, coat protein (CP), polymerase (POL) and an intergenic (POL/p33) region using quantitative RTPCR, revealed consistent differences in abundance for each of these RNAs among flowers, stems, young fruits and leaves of infected orange trees. CTV p23 RNAs accumulated at highest levels, reaching a maximum in the flowers and the lowest levels in the leaves, while POL RNAs consistently accumulated at low levels in all tissues tested. A PCR-amplified dig-labelled CTV p23 DNA probe was applied to stem and leaf prints, and to crude and total RNA leaf extracts, using non isotopic hybridization. This technique, when applied to stem or leaf prints, and particularly to total RNA, unequivocally provided strong signals with minimal backgrounds. Moreover, an antiserum with high sensitivity and specificity of CTV detection as shown by DAS and immunoprint ELISA was produced against bacterially-expressed CTV CP. In the former method, stems and flowers contained higher levels of CTV CP when compared to leaf extracts. Taking into account Cretan geography and the importance of citrus to the island, systematic surveys for CTV eradication, sustainable control measurements and epidemiological studies need to be undertaken. The observations, materials and methods presented here may assist all three tasks at local and national level. [ABSTRACT FROM AUTHOR]

Healthy I E. aureum i plants mechanically inoculated with sap from TSWV-infected I E. aureum i plants showed mild mosaic and systemic necrosis at 14 days post-inoculation. Keywords: Epipremnum aureum; Korea; tomato spotted wilt virus EN Epipremnum aureum Korea tomato spotted wilt virus 381 381 1 02/24/22 20220201 NES 220201 I Epipremnum aureum i (family Araceae), a tropical vine commonly known as pothos, is grown commercially worldwide for ornamental use as a garden and indoor plant (Tian et al. [3]). [Extracted from the article]