Cherry leaf roll virus (walnut ringspot).

2021 ◽  
Author(s):  
Susanne Von Bargen ◽  
Carmen Büttner ◽  
Juliane Langer
Keyword(s):  
Leaf Roll ◽  
Seed Transmission ◽  
Plant Viruses ◽  
Long Distance ◽  
Long Distance Transport ◽  
Cherry Leaf Roll Virus ◽  
Quarantine Pathogen ◽  
Olive Trees ◽  
Production Areas ◽  
Risk Potential

Abstract Seed transmission of CLRV is a threat to gene bank contamination. CLRV-contaminated vegetative propagation material and seeds are prone to extremely long-distance transport. Due to this risk potential, CLRV is included in the list of plant viruses that should be closely monitored during sanitary production of propagative material, especially for walnut and olive trees (Bassi and Martelli, 2003). CLRV is treated as an A2 quarantine pathogen in Rubus in the EPPO region, a virus-free certification scheme for Rubus was developed by OEPP/EPPO (1994). In cherry (Kegler et al., 1972; Bush, 2005), walnut (Mircetich et al., 1980; Delbos et al., 1983; Nemeth et al., 1990) and olive production areas, CLRV infections are consistently occurring (Langer et al., 2010; Büttner et al., 2011); crop losses due to CLRV infections were reported for cherry (Kegler et al., 1972; Bush, 2005), walnut (Mircetich et al., 1980; Delbos et al., 1983; Nemeth et al., 1990) and raspberry (Jones and Wood, 1978).In birch species native to Fennoscandia virus-like symptoms on leaves (vein banding, leaf roll, mottling), partially adherent with progressive loss of vitality or death of twigs and branches have been spreading rapidly since 2002 with up to 85% of the tested trees being infected with CLRV (Jalkanen et al., 2007; von Bargen et al., 2009a).

scholarly journals Virus Surveys in Olive Orchards in Greece Identify Olive Virus T, a Novel Member of the Genus Tepovirus

Pathogens ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 574
Author(s):  
Evanthia Xylogianni ◽  
Paolo Margaria ◽  
Dennis Knierim ◽  
Kyriaki Sareli ◽  
Stephan Winter ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Leaf Roll ◽  
Virus Infections ◽  
Northern Greece ◽  
Coat Protein Region ◽  
Cherry Leaf Roll Virus ◽  
Leaf Yellowing ◽  
Olive Trees ◽  
Olive Varieties ◽  
Viral Sequences

Field surveys were conducted in Greek olive orchards from 2017 to 2020 to collect information on the sanitary status of the trees. Using a high-throughput sequencing approach, viral sequences were identified in total RNA extracts from several trees and assembled to reconstruct the complete genomes of two isolates of a new viral species of the genus Tepovirus (Betaflexiviridae), for which the name olive virus T (OlVT) is proposed. A reverse transcription–polymerase chain reaction assay was developed which detected OlVT in samples collected in olive growing regions in Central and Northern Greece, showing a virus prevalence of 4.4% in the olive trees screened. Sequences of amplified fragments from the movement–coat protein region of OlVT isolates varied from 75.64% to 99.35%. Three olive varieties (Koroneiki, Arbequina and Frantoio) were infected with OlVT via grafting to confirm a graft-transmissible agent, but virus infections remained latent. In addition, cucumber mosaic virus, olive leaf yellowing-associated virus and cherry leaf roll virus were identified.

scholarly journals First Report of Nasturtium as a Natural Host of Cherry leaf roll virus on Amsterdam Island

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 477-477 ◽  
Author(s):  
A. Marais ◽  
C. Faure ◽  
T. Candresse ◽  
M. Hullé
Keyword(s):  
Natural Infection ◽  
Leaf Roll ◽  
Plant Viruses ◽  
Natural Host ◽  
Mechanical Transmission ◽  
Sequence Information ◽  
Coding Region ◽  
Rt Pcr ◽  
First Report ◽  
Cherry Leaf Roll Virus

Cherry leaf roll virus (CLRV) is a well-known virus belonging to the genus Nepovirus, but unlike most members of this genus, it is not known to be transmitted by nematodes but only through seeds and pollen. Since its first description in 1955 on Prunus avium L. in England (1), CLRV has been shown to have a worldwide distribution and a wide natural host range. During a survey of plant viruses in the French sub-Antarctic islands, samples from nasturtium plants (Tropaeolum majus), an introduced plant species, showing symptoms of leaf mosaic, deformation, and veinal necrosis were collected on Amsterdam Island. Upon mechanical transmission with sap extracts, necrotic ringspot and oak-leaf symptoms typical of Nepovirus infection were observed on the leaves of inoculated Nicotiana clevelandii and N. tabacum plants. Inoculation of healthy nasturtium plants resulted in mosaic and pin-point necrosis symptoms. Electron microscopy on negatively stained sap extracts revealed the presence of icosahedral virions, 28 to 30 nm in diameter, in the symptomatic Nicotiana leaves. Amplification by reverse transcription (RT)-PCR with a polyvalent test, which identifies viruses belonging to the family Comoviridae (2), yielded the expected 248-bp fragment. Sequencing of the cloned amplicon showed 80% nucleotide and 90% amino acid identity with a part of the RNA dependent RNA polymerase (RdRp) of CLRV (CAE83562). To confirm the presence of CLRV, an approximate 4.6-kbp cDNA fragment was PCR amplified from double-stranded RNAs purifed from infected Nicotiana plants using the sense primer 5′-GTGGGACTGCCATGCACCTACTC-3′ and an oligo-T25 as antisense primer. This PCR product (GenBank Accession No. GU167974) spans the region between the VPg gene and the polyA tail at the 3′ end of the genome and thus provides approximately 2.8 kb of new internal sequence information on RNA1 of CLRV. The presence of CLRV in the initial nasturtium samples was confirmed with a CLRV-specific RT-PCR assay that amplifies the 3′ non-coding region of the CLRV genome (3). Sequence of the amplified fragment showed it to be identical to the corresponding part of the 3′ non-coding region of 4.6-kbp clone obtained from the CLRV isolate mechanically transmitted to the N. tabacum and N. clevelandii plants. Experimental infection of nasturtium by CLRV has been reported (4), but to the best of our knowledge these results represent the first report of natural infection of T. majus by CLRV. Given its seed transmissible character in many hosts, CLRV likely was introduced in infected seeds of T. majus imported to the remote sub-Antarctic Amsterdam Island. References: (1) R. Cropley. Ann. Appl. Biol. 49:524, 1961. (2) V. Maliogka et al. J. Phytopathol. 152:404, 2004. (3) K. Rebenstorf et al. J. Virol. 80:2453, 2006. (4) K. Schmelzer. Phytopathol. Z. 55:317, 1966.

scholarly journals Host Species-Dependent Population Structure of a Pollen-Borne Plant Virus, Cherry Leaf Roll Virus

2006 ◽  
Vol 80 (5) ◽  
pp. 2453-2462 ◽  
Author(s):  
Kathrin Rebenstorf ◽  
Thierry Candresse ◽  
Marie Josée Dulucq ◽  
Carmen Büttner ◽  
Christian Obermeier
Keyword(s):  
Host Plant ◽  
Host Species ◽  
Molecular Diversity ◽  
Leaf Roll ◽  
Significant Degree ◽  
Plant Viruses ◽  
Genomic Region ◽  
Plant Host ◽  
Genomic Rnas ◽  
Cherry Leaf Roll Virus

ABSTRACT Cherry leaf roll virus (CLRV) belongs to the Nepovirus genus within the family Comoviridae. It has a host range which includes a number of wild tree and shrub species. The serological and molecular diversity of CLRV was assessed using a collection of isolates and samples recovered from woody and herbaceous host plants from different geographical origins. Molecular diversity was assessed by sequencing a short (375-bp) region of the 3′ noncoding region (NCR) of the genomic RNAs while serological diversity was assessed using a panel of seven monoclonal antibodies raised initially against a walnut isolate of CLRV. The genomic region analyzed was shown to exhibit a significant degree of molecular variability with an average pairwise divergence of 8.5% (nucleotide identity). Similarly, serological variability proved to be high, with no single monoclonal antibody being able to recognize all isolates analyzed. Serological and molecular phylogenetic reconstructions showed a strong correlation. Remarkably, the diversity of CLRV populations is to a large extent defined by the host plant from which the viral samples are originally obtained. There are relatively few reports of plant viruses for which the genetic diversity is structured by the host plant. In the case of CLRV, we hypothesize that this situation may reflect the exclusive mode of transmission in natural plant populations by pollen and by seeds. These modes of transmission are likely to impose barriers to host change by the virus, leading to rapid biological and genetic separation of CLRV variants coevolving with different plant host species.

scholarly journals Detection and phylogeny of viruses in native Albanian olive varieties

2021 ◽  
Vol 60 (1) ◽  
pp. 165-174
Author(s):  
Toufic ELBEAINO ◽  
Magdalena CARA ◽  
Shpend SHAHINI ◽  
Pasko PANDELI
Keyword(s):  
Mosaic Virus ◽  
Leaf Roll ◽  
Olive Tree ◽  
Ringspot Virus ◽  
Arabis Mosaic Virus ◽  
Cherry Leaf Roll Virus ◽  
Leaf Yellowing ◽  
Standard Quality ◽  
Olive Trees ◽  
Olive Varieties

Forty samples representing 14 native Albanian and two foreign olive varieties were collected from an olive varietal collection plot in the Valias region (Tirana, Albania). The samples were assayed by RT-PCR for presence of olive-infecting viruses, including arabis mosaic virus (ArMV), cherry leaf roll virus (CLRV), cucumber mosaic virus (CMV), olive latent ringspot virus (OLRSV), olive latent virus 1 (OLV-1), olive leaf yellowing-associated virus (OLYaV), strawberry latent ringspot virus (SLRSV) and by PCR for the bacterium Xylella fastidiosa (Xf). Ninety-eight percent of the samples were infected with at least one virus. OLYaV was the most prevalent (85% of samples), followed by OLV-1 (50%), OLRSV (48%), CMV (28%), SLRSV (3%) and CLRV (5%), whereas ArMV and Xf were absent. Fifty-five percent of the samples were infected with one virus, 13% with two viruses, 20% with three, and 5% with four. Analyses of the nucleotide sequences of the Albanian virus isolates generally showed low genetic variability, and that most were phylogenetically related to Mediterranean isolates, in particular to those from Greece and Italy. Five olive trees, representing three native cultivars (‘Managiel’, ‘Kalinjot’ and ‘Kushan-Preze’) and one foreign (‘Leccino’), were found to be plants of the Conformitas Agraria Communitatis (“CAC”) category i.e. free of ArMV, CLRV, SLRSV and OLYaV. Only one tree of the native cultivar ‘Ulliri i kuq’ was free of all tested viruses, so this is plant material of the “Virus-tested” category. Olives derived from both categories could be used for propagation of standard quality plant materiel in a future certification programme for olive in Albania. This is the first report of CLRV, OLRSV, CMV and OLV-1 in Albania. The study also reveals the precarious health status of native olive varieties in the Valias varietal collection plot. However, the discovery of six plants representing two certifiable categories is a first step in a future olive tree certification program in the country.

The Fine Structure of Phloem Cells

1985 ◽  
Vol 43 ◽  
pp. 632-635
Author(s):  
James Cronshaw
Keyword(s):  
Structural Studies ◽  
High Concentration ◽  
Long Distance ◽  
Phloem Tissue ◽  
Sieve Elements ◽  
Long Distance Transport ◽  
P Protein ◽  
Companion Cells ◽  
Electron Microscopical ◽  
Distance Transport

Long distance transport in plants takes place in phloem tissue which has characteristic cells, the sieve elements. At maturity these cells have sieve areas in their end walls with specialized perforations. They are associated with companion cells, parenchyma cells, and in some species, with transfer cells. The protoplast of the functioning sieve element contains a high concentration of sugar, and consequently a high hydrostatic pressure, which makes it extremely difficult to fix mature sieve elements for electron microscopical observation without the formation of surge artifacts. Despite many structural studies which have attempted to prevent surge artifacts, several features of mature sieve elements, such as the distribution of P-protein and the nature of the contents of the sieve area pores, remain controversial.

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