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A newly characterized garlic virus, provisionally named garlic yellow curl virus (GYCV), is a Betaflexiviridae virus first reported in China in 2023. In this study, GYCV was also discovered in the Philippines through transcriptome sequencing of the Batanes White garlic variety from Batanes, the northernmost province of the country. The complete RNA sequence of GYCV from the Philippines (GenBank OR354819) spans 8184 bp, and the genome organization is typical of the subfamily Quinvirinae, which comprises five open reading frames: one replicase gene, three triple gene block protein genes, and one coat protein gene. The complete genome shares its closest relatedness with the first GYCV from China, showing approximately 76% genetic similarity and clustering within the GYCV clade in the phylogenetic tree. Additionally, analysis of the replicase and coat protein genes confirmed the virus's identity with > 72% similarity to GYCV. Among the Betaflexiviridae viruses, the GYCV clade exhibits a higher degree of relatedness to another new and unclassified garlic yellow mosaic-associated virus (GYMaV) recently reported in Brazil and Korea. The presence of GYCV in the Batanes White garlic samples was further confirmed through reverse transcription PCR and subsequent sequencing using primers designed from the generated complete genome. To date, this emerging virus does not belong to any known genera of viruses within the Betaflexiviridae family. This study represents the first detection and complete genome sequencing of GYCV in the Philippines and the second after China. These findings hold significance for virus management and resistance breeding programs aimed at safeguarding the country's garlic industry. [ABSTRACT FROM AUTHOR]

The complete genome of a new virus belonging to the family Betaflexiviridae was identified in garlic and sequenced by next-generation sequencing and reverse transcription PCR. The complete RNA genome (GenBank accession number OP021693) is 8191 nucleotides in length, excluding the 3’ poly(A) tail, and contains five open reading frames (ORFs). These open reading frames encode the viral replicase, triple gene block, and coat protein, and the genome organization is typical of members of the subfamily Quinvirinae. The virus has been tentatively named "garlic yellow curl virus" (GYCV). Phylogenetic analysis suggested that it represents an independent evolutionary lineage in the subfamily, clustering with the currently unclassified garlic yellow mosaic associated virus (GYMaV) and peony betaflexivirus 1 (PeV1). Differences between the phylogenies inferred for the replicase and coat protein indicate that the new virus does not belong to any established genus of the family Betaflexiviridae. This is the first report of GYCV in China. [ABSTRACT FROM AUTHOR]

We identified a tentative novel positive-strand RNA virus from Rudbeckia sp., namely, Rudbeckia citrivirus A (RuCVA). The complete genome sequence of the novel virus was 8821 nucleotides in length, excluding the poly(A) tail. It has three open reading frames (ORFs): a putative polyprotein, a movement protein, and a coat protein. Phylogenetic analysis showed that the virus was more closely related to Citrus leaf blotch virus isolates and unassigned citriviruses. The sequence identity of the virus with other citriviruses was lower than 56.9% at the complete nucleotide sequence level. For each ORF, the sequence identity was lower than 64.2% at the nucleotide level and 67.8% at the amino acid level. These results satisfied the species demarcation criteria for Betaflexiviridae. Therefore, we suggest that RuCVA is a novel member of the genus Citrivirus. [ABSTRACT FROM AUTHOR]

The viromic profile of Polyscias balfouriana cv. Marginata, a perennial woody and ornamental plant, was determined using ribosomal RNA-depleted total RNA (rRNA-depleted totRNA) sequencing. Five viruses (i.e., polyscias mosaic virus, PoMV; one potential novel rhabdovirus; and three novel viruses of Betaflexiviridae and Closteroviridae) were detected and prevalence-surveyed in Hainan province, China. The genomes of polyscias capillovirus 1 (PCaV-1) and polyscias citrivirus 1 (PCiV-1) of family Betaflexiviridae were completed, and the genomes of polyscias crinivirus 1 (PCrV-1) of Closteroviridae were nearly completed lacking the 5′ and 3′ termini. PCaV-1 shares 68% genome nucleotide (nt) identity and 66% replicase (Rep) amino acid (aa) identity with homologues in apple stem grooving virus (ASGV). PCiV-1 shares 65% genome nt identity and 64% Rep aa identity with homologs in citrus leaf blotch virus (CLBV). Meeting the species demarcation criteria, PCaV-1 and PCiV-1 were considered to be new species in genera Capillovirus and Citrivirus, respectively. PCrV-1 shares high genome nt identity (62%), heat shock protein 70-like protein (HSP70h) and RNA-dependent RNA polymerase (RdRp) aa identity (78–80%) with homologues in tomato chlorosis virus (ToCV). We tentatively consider PCrV-1 to be an unclassified member of the Crinivirus genus. PoMV, PCaV-1, PCiV-1, and PCrV-1 are the prevalent viruses with >73% occurrence in the Xinglong Tropical Botanical Garden, Hainan, China. [ABSTRACT FROM AUTHOR]

Grapevine virus A (GVA) is a phloem-restricted virus (genus Vitivirus, family Betaflexiviridae) that cause crop losses of 5–22% in grapevine cultivars, transmitted by different species of pseudococcid mealybugs, the mealybug Heliococcus bohemicus, and by the scale insect Neopulvinaria innumerabilis. In this work, we studied the genetic structure and molecular variability of GVA, ascertaining its presence and spread in different commercial vineyards of four Sicilian provinces (Italy). In total, 11 autochthonous grapevine cultivars in 20 commercial Sicilian vineyards were investigated, for a total of 617 grapevine samples. Preliminary screening by serological (DAS-ELISA) analysis for GVA detection were conducted and subsequently confirmed by molecular (RT-PCR) analysis. Results showed that 10 out of the 11 cultivars analyzed were positive to GVA, for a total of 49 out of 617 samples (8%). A higher incidence of infection was detected on 'Nerello Mascalese', 'Carricante', 'Perricone' and 'Nero d'Avola' cultivars, followed by 'Alicante', 'Grecanico', 'Catarratto', 'Grillo', 'Nerello Cappuccio' and 'Zibibbo', while in the 'Moscato' cultivar no infection was found. Phylogenetic analyses carried out on the coat protein (CP) gene of 16 GVA sequences selected in this study showed a low variability degree among the Sicilian isolates, closely related with other Italian isolates retrieved in GenBank, suggesting a common origin, probably due to the exchange of infected propagation material within the Italian territory. [ABSTRACT FROM AUTHOR]

High-throughput sequencing (HTS) of three pear trees (Pyrus communis) resulted in the identification of two isolates of a Tepovirus species and one isolate of a Robigovirus species, both genera from the family Betaflexiviridae and never reported in pears. Their complete genomes were fully characterized, revealing genomes of about 6.8 kb (Tepovirus) and 8.4 kb (Robigovirus). According to the species demarcation criteria in the family Betaflexiviridae, the tepovirus isolates reported here are divergent isolates of Prunus Virus T (PrVT). The robigovirus isolate had enough difference in pairwise comparison with its closer related species, cherry virus Turkey (CVTR) and it should be considered a new species of this genus, tentatively named as pomes virus Greece (PVGR). A survey was conducted using specific primers designed for each of the viruses and one additional pear accession tested positive to PrVT. Furthermore, both viruses were successfully graft-transmissible to Malus domestica or Malus micromalus, suggesting their potential to be transmitted to Malus species. This study expands the list of viruses infecting pome fruit trees and augments our knowledge on the molecular diversity and host range evolution of betaflexiviruses. [ABSTRACT FROM AUTHOR]

Yellow mosaic disease in winter wheat is usually attributed to the infection by bymoviruses or furoviruses; however, there is still limited information on whether other viral agents are also associated with this disease. To investigate the wheat viromes associated with yellow mosaic disease, we carried out de novo RNA sequencing (RNA-seq) analyses of symptomatic and asymptomatic wheat-leaf samples obtained from a field in Hokkaido, Japan, in 2018 and 2019. The analyses revealed the infection by a novel betaflexivirus, which tentatively named wheat virus Q (WVQ), together with wheat yellow mosaic virus (WYMV, a bymovirus) and northern cereal mosaic virus (a cytorhabdovirus). Basic local alignment search tool (BLAST) analyses showed that the WVQ strains (of which there are at least three) were related to the members of the genus Foveavirus in the subfamily Quinvirinae (family Betaflexiviridae). In the phylogenetic tree, they form a clade distant from that of the foveaviruses, suggesting that WVQ is a member of a novel genus in the Quinvirinae. Laboratory tests confirmed that WVQ, like WYMV, is potentially transmitted through the soil to wheat plants. WVQ was also found to infect rye plants grown in the same field. Moreover, WVQ-derived small interfering RNAs accumulated in the infected wheat plants, indicating that WVQ infection induces antiviral RNA silencing responses. Given its common coexistence with WYMV, the impact of WVQ infection on yellow mosaic disease in the field warrants detailed investigation.

Grapevine leaf mottling and deformation is a novel grapevine disease that has been associated with grapevine Pinot gris virus (GPGV). The virus was observed exclusively inside membrane-bound structures in the bundle sheath cells of the infected grapevines. As reported widely in the literature, many positive-sense single-stranded RNA viruses modify host-cell membranes to form a variety of deformed organelles, which shelter viral genome replication from host antiviral compounds. Morphologically, the GPGV-associated membranous structures resemble the deformed endoplasmic reticulum described in other virus-host interactions. In this study we investigated the GPGV-induced membranous structures observed in the bundle sheath cells of infected plants. The upregulation of different ER stress-related genes was evidenced by RT-qPCR assays, further confirming the involvement of the ER in grapevine/GPGV interaction. Specific labelling of the membranous structures with an antibody against luminal-binding protein identified them as ER. Double-stranded RNA molecules, which are considered intermediates of viral replication, were localised exclusively in the ER-derived structures and indicated that GPGV exploited this organelle to replicate itself in a shelter niche. Novel analyses using focussed ion-beam scanning electron microscopy (FIB-SEM) were performed in grapevine leaf tissues to detail the three-dimensional organisation of the ER-derived structures and their remodelling due to virus replication. Grapevine leaf mottling and deformation (GLMD) is a novel grapevine disease that has been associated with grapevine Pinot gris virus (GPGV). Despite the increase in the number of reports describing GLMD in vineyards worldwide, the literature still lacks information on virus–grapevine interactions at the cytological and molecular level. The results reported in this work contribute to understanding the biology of GPGV in its natural host and to improving knowledge of the novel GLMD disease, whose aetiology is still poorly understood. [ABSTRACT FROM AUTHOR]

This study provides the first report on the complete genome sequence and host range study of eggplant infecting Carlavirus (IND-SHM isolate) causing mosaic disease in eggplant. We report the complete RNA genome sequence of 8669 nucleotides, excluding poly (A) tail of eggplant infecting Carlavirus (IND-SHM) isolate originating from Telangana State of India. Host range study showed that this virus is restricted to eggplant and tomato, causing mild to severe mosaic and mottling of leaves. The phylogenetic and sequence analysis revealed that replicase and coat protein of this isolate share 85% and 83% identity at nucleotide level respectively with hot pepper infecting Pepper virus A (KU726694, KU923763). Genome sequence identity and phylogenetic analysis suggests that our isolate IND-SHM is the strain of Pepper virus A. [ABSTRACT FROM AUTHOR]

Yellow mosaic disease in winter wheat is usually attributed to the infection by bymoviruses or furoviruses; however, there is still limited information on whether other viral agents are also associated with this disease. To investigate the wheat viromes associated with yellow mosaic disease, we carried out de novo RNA sequencing (RNA-seq) analyses of symptomatic and asymptomatic wheat-leaf samples obtained from a field in Hokkaido, Japan, in 2018 and 2019. The analyses revealed the infection by a novel betaflexivirus, which tentatively named wheat virus Q (WVQ), together with wheat yellow mosaic virus (WYMV, a bymovirus) and northern cereal mosaic virus (a cytorhabdovirus). Basic local alignment search tool (BLAST) analyses showed that the WVQ strains (of which there are at least three) were related to the members of the genus Foveavirus in the subfamily Quinvirinae (family Betaflexiviridae). In the phylogenetic tree, they form a clade distant from that of the foveaviruses, suggesting that WVQ is a member of a novel genus in the Quinvirinae. Laboratory tests confirmed that WVQ, like WYMV, is potentially transmitted through the soil to wheat plants. WVQ was also found to infect rye plants grown in the same field. Moreover, WVQ-derived small interfering RNAs accumulated in the infected wheat plants, indicating that WVQ infection induces antiviral RNA silencing responses. Given its common coexistence with WYMV, the impact of WVQ infection on yellow mosaic disease in the field warrants detailed investigation. [ABSTRACT FROM AUTHOR]

Grapevine virus A (GVA) is a phloem-restricted virus (genus Vitivirus, family Betaflexiviridae) that cause crop losses of 5–22% in grapevine cultivars, transmitted by different species of pseudococcid mealybugs, the mealybug Heliococcus bohemicus, and by the scale insect Neopulvinaria innumerabilis. In this work, we studied the genetic structure and molecular variability of GVA, ascertaining its presence and spread in different commercial vineyards of four Sicilian provinces (Italy). In total, 11 autochthonous grapevine cultivars in 20 commercial Sicilian vineyards were investigated, for a total of 617 grapevine samples. Preliminary screening by serological (DAS-ELISA) analysis for GVA detection were conducted and subsequently confirmed by molecular (RT-PCR) analysis. Results showed that 10 out of the 11 cultivars analyzed were positive to GVA, for a total of 49 out of 617 samples (8%). A higher incidence of infection was detected on ‘Nerello Mascalese’, ‘Carricante’, ‘Perricone’ and ‘Nero d’Avola’ cultivars, followed by ‘Alicante’, ‘Grecanico’, ‘Catarratto’, ‘Grillo’, ‘Nerello Cappuccio’ and ‘Zibibbo’, while in the ‘Moscato’ cultivar no infection was found. Phylogenetic analyses carried out on the coat protein (CP) gene of 16 GVA sequences selected in this study showed a low variability degree among the Sicilian isolates, closely related with other Italian isolates retrieved in GenBank, suggesting a common origin, probably due to the exchange of infected propagation material within the Italian territory.

The viromic profile of Polyscias balfouriana cv. Marginata, a perennial woody and ornamental plant, was determined using ribosomal RNA-depleted total RNA (rRNA-depleted totRNA) sequencing. Five viruses (i.e., polyscias mosaic virus, PoMV; one potential novel rhabdovirus; and three novel viruses of Betaflexiviridae and Closteroviridae) were detected and prevalence-surveyed in Hainan province, China. The genomes of polyscias capillovirus 1 (PCaV-1) and polyscias citrivirus 1 (PCiV-1) of family Betaflexiviridae were completed, and the genomes of polyscias crinivirus 1 (PCrV-1) of Closteroviridae were nearly completed lacking the 5′ and 3′ termini. PCaV-1 shares 68% genome nucleotide (nt) identity and 66% replicase (Rep) amino acid (aa) identity with homologues in apple stem grooving virus (ASGV). PCiV-1 shares 65% genome nt identity and 64% Rep aa identity with homologs in citrus leaf blotch virus (CLBV). Meeting the species demarcation criteria, PCaV-1 and PCiV-1 were considered to be new species in genera Capillovirus and Citrivirus, respectively. PCrV-1 shares high genome nt identity (62%), heat shock protein 70-like protein (HSP70h) and RNA-dependent RNA polymerase (RdRp) aa identity (78–80%) with homologues in tomato chlorosis virus (ToCV). We tentatively consider PCrV-1 to be an unclassified member of the Crinivirus genus. PoMV, PCaV-1, PCiV-1, and PCrV-1 are the prevalent viruses with >73% occurrence in the Xinglong Tropical Botanical Garden, Hainan, China.

The genome sequence of a novel RNA virus was identified by analyzing transcriptome data obtained from the stem sample of a blue agave (Agave tequilana) plant. Sequence comparison and phylogenetic analysis showed that the RNA virus, Agave virus T (AgVT), was a new member of the genus Tepovirus in the family Betaflexiviridae. AgVT genome had three open reading frames: a 1605-amino acid (aa) replicase (REP), 355-aa movement protein (MP), and 220-aa coat protein (CP). Phylogenetic analyses based on the REP, MP, and CP sequences of AgVT, previously reported tepoviruses, and other Betaflexiviridae viruses revealed that tepoviruses could be classified into two subclades: "potato virus T (PVT)-clade" and "Prunus virus T (PrVT)-clade." PVT, the type species and founding member of the genus Tepovirus, belong to "PVT-clade" along with AgVT, while the other five tepoviruses belong to "PrVT-clade." The genome sequence of AgVT may be useful for studying the phylogenetic relationships between tepoviruses and other closely related viruses. [ABSTRACT FROM AUTHOR]

In this work, a novel ssRNA (+) viral genomic sequence with gene organization typical of members of the subfamily Quinvirinae (family Betaflexiviridae) was identified using high- throughput sequencing data of date palm obtained from the Sequence Read Archive database. The viral genome sequence consists of 7860 nucleotides and contains five ORFs encoding for the replication protein (Rep), triple gene block proteins 1, 2, 3 (TGB 1, 2, and 3), and coat protein (CP). Phylogenetic analysis based on the Rep and the CP amino acid sequences showed the closest relationship to garlic yellow mosaic-associated virus (GYMaV). Based on the demarcation criteria of the family Betaflexiviridae, this new virus, provisionally named date palm virus A (DPVA), could constitute a member of a novel genus. However, considering that DPVA and GYMaV share the same genomic organization and that they cluster together on the Rep phylogenetic analysis, they could also constitute a novel genus together, highlighting the necessity of a revision of the taxonomic criteria of the family Betaflexiviridae. [ABSTRACT FROM AUTHOR]

Contigs with the highest sequence similarity (73%) to Apricot pseudo-chlorotic leaf spot virus (genus Trichovirus, family Betaflexiviridae) were identified by high-throughput sequencing from a symptomless sweet cherry accession. The complete genome sequence of this new virus is 7460 nucleotides, excluding the 3′ poly(A) tail. Its genome organization is very similar to several trichoviruses infecting fruit trees, with three open reading frames encoding putative replicase, movement protein and coat protein (CP). The virus shares amino acid sequence identities of 60–73% at replicase and 53–76% at CP with other trichoviruses. Phylogenetic analyses group it and other trichoviruses in a cluster. These results support that this virus, which is tentatively named cherry latent virus 1, should be considered a new member in the genus Trichovirus. [ABSTRACT FROM AUTHOR]

The cottony grape scale Pulvinaria vitis is a scale insect colonizing grapevine; however, its capacity as a vector of grapevine viruses is poorly known in comparison to other scale species that are vectors of viral species in the genera Ampelovirus and Vitivirus. The ability of P. vitis to transmit the ampeloviruses Grapevine leafroll-associated viruses [GLRaV]−1, −3, and −4, and the vitivirus Grapevine virus A (GVA), to healthy vine cuttings was assessed. The scale insects used originated from commercial vine plots located in Alsace, Eastern France. When nymphs sampled from leafroll-infected vineyard plants were transferred onto healthy cuttings, only one event of transmission was obtained. However, when laboratory-reared, non-viruliferous nymphs were allowed to acquire viruses under controlled conditions, both first and second instar nymphs derived from two vineyards were able to transmit GLRaV−1 and GVA. This is the first report of GLRaV−1 and GVA transmission from grapevine to grapevine by this species.

Betaflexiviridae is a family of plant-infecting RNA viruses with 11 recognized genera, of which genomes have diverse organization with three to six open reading frames (ORFs). A genome sequence of a novel Betaflexiviridae species, named Salvia divinorum RNA virus 1 (SdRV1), was identified in Salvia divinorum, herbal mint plant with hallucinogenic properties. The SdRV1 genome was predicted to have four ORFs encoding a replicase polyprotein (REP), a movement protein (MP), a coat protein (CP), and a putative nucleic acid-binding protein (NBP). Phylogenetic analyses based on the REP, MP, and CP sequences indicated that SdRV1 is most closely related to members of the genus Citrivirus. However, the genome organization of SdRV1 is the same as that of the genus Prunevirus. Moreover, the SdRV1 NBP had greatest sequence similarity with members of the genus Carlavirus. A complex evolutionary history involving ancestors of these three genera might have resulted in the unique phylogenetic position of SdRV1, which could be considered the founding member of a new genus in the family Betaflexiviridae. The genome sequence of SdRV1 might be useful for studies on the evolution of Betaflexiviridae. [ABSTRACT FROM AUTHOR]

Analysis of a transcriptome dataset obtained from tissue samples of the eelgrass Zostera muelleri, an aquatic flowering plant species of the family Zosteraceae, yielded three genome sequence contigs of a novel RNA virus. Sequence comparison and phylogenetic analysis revealed that the novel RNA virus, named Zostera virus T (ZoVT), belongs to the genus Tepovirus of the family Betaflexiviridae. The three genome contigs of ZoVT showed 88.2-97.2% nucleotide sequence identity to each other, indicating that they descended from a common ancestor. The ZoVT genome contains three open reading frames (ORFs): ORF1 encodes a 1816 amino acid (aa) replicase (REP) with RNA-dependent RNA polymerase (RdRp) activity; ORF2, a 398 aa movement protein (MP); and ORF3, a 240 aa coat protein (CP). The phylogenetic analysis using REP sequences of ZoVT and other Betaflexiviridae viruses showed that Prunus virus T is the closest known virus to ZoVT, whereas potato virus T, the type species of the genus Tepovirus, is the second closest virus. Genome sequences of ZoVT, which is the third tepovirus species identified to date, may be useful for investigating the evolution and molecular biology of tepoviruses. [ABSTRACT FROM AUTHOR]

Vitiviruses are ssRNA(+) viruses in the family Betaflexiviridae (subfamily Trivirinae). There are currently 10 ICTV recognized virus species in the genus; nevertheless, the extended use of NGS technologies is rapidly expanding their diversity and official recognition of six more have been proposed recently. Here, we present the characterization of a novel virus from grapevine, which fits the genomic architecture and evolutionary constraints to be classified within the Vitivirus genus. The detected virus sequence is 7607 nt long, including a typical genome organization of ORFs encoding a replicase (RP), a 22 kDa protein, a movement protein, a coat protein (CP) and a nucleic acid binding protein. Phylogenetic analyses based on the predicted RP and CP proteins unequivocally place the new virus within the Vitivirus genus. Multiple independent RNAseq data confirmed the presence of the detected virus in berries at diverse developmental stages. Additionally, we detected, confirmed, and assembled virus sequences from grapevine samples of distinct cultivars from America, Europe, Asia and Oceania, sharing 74.4%–97.8% nt identity, suggesting that the identified virus is widely distributed and diverse. We propose the name grapevine virus L (GVL) to the detected Vitivirus. [ABSTRACT FROM AUTHOR]

Ginseng (Panax ginseng) is a valuable herb that is widely cultivated in Korea, China, and Japan because it contains a variety of pharmacologically active substances with a wide range of positive effects on human health. Identification and prevention of disease-causing viral pathogens of ginseng is important for improving the yield and quality of ginseng-derived bioactive molecules. In this study, the genome sequence of the virus Panax ginseng flexivirus 1 (PgFV1) was identified from a ginseng root transcriptome data set. Sequence comparison and phylogenetic analysis showed that PgFV1 is a novel plant RNA virus species of the genus Foveavirus (the family Betaflexiviridae). Foveaviruses have flexuous and filamentous virions with a single-stranded positive-sense mono-segmented RNA genome. Its infection causes diseases with mosaic and ringspot symptoms in the stems and leaves. The PgFV1 genome encodes for 5 open reading frames: a replicase polyprotein for viral genome replication, 3 triple gene block proteins for viral cell-to-cell movement, and coat protein. Phylogenetic trees inferred from replicase polyprotein or coat protein sequences showed that PgFV1 is most closely related to grapevine virus T. PgFV1 is the first foveavirus identified to be associated with ginseng. Given the potential pathogenic features of previously known foveaviruses and importance of ginseng in the health industry, the PgFV1 genome sequence may be highly useful for studying ginseng foveaviruses. [ABSTRACT FROM AUTHOR]

A novel member of the Carlavirus genus, provisionally named soybean carlavirus 1 (SCV1), was discovered by RNA-seq analysis of randomly collected soybean leaves in Illinois, USA. The SCV1 genome contains six open reading frames that encode a viral replicase, triple gene block proteins, a coat protein (CP) and a nucleic acid binding protein. The proteins showed highest amino acid sequence identities with the corresponding proteins of red clover carlavirus A (RCCVA). The predicted amino acid sequence of the SCV1 replicase was only 60.6% identical with the replicase of RCCVA, which is below the demarcation criteria for a new species in the family Betaflexiviridae. The predicted replicase and CP amino acid sequences of four SCV1 isolates grouped phylogenetically with those of members of the Carlavirus genus in the family Betaflexiviridae. The features of the encoded proteins, low nucleotide and amino acid sequence identities of the replicase with the closest member, and the phylogenetic grouping suggest SCV1 is a new member of the Carlavirus genus.

Banana mild mosaic virus (BanMMV) (Betaflexiviridae, Quinvirinae, unassigned species) is a filamentous virus belonging to the Betaflexiviridae family. It infects Musa spp. with a very wide geographic distribution. The genome variability of plant viruses, including the members of the Betaflexiviridae family, makes their molecular detection by specific primers particularly challenging. During routine indexing of the Musa germplasm accessions, a discrepancy was observed between electron microscopy and immunocapture (IC) reverse transcription (RT) polymerase chain reaction (PCR) test results for one asymptomatic accession. Filamentous viral particles were observed while molecular tests failed to amplify any fragment. The accession underwent high-throughput sequencing and two complete genomes of BanMMV with 75.3% of identity were assembled. Based on these sequences and on the 54 coat protein sequences available from GenBank, a new forward primer, named BanMMV CP9, compatible with Poty1, an oligodT reverse primer already used in diagnostics, was designed. A retrospective analysis of 110 different germplasm accessions from diverse origins was conducted, comparing BanMMCP2 and BanMMV CP9 primers. Of these 110 accessions, 16 tested positive with both BanMMCP2 and BanMMV CP9, 3 were positive with only BanMMCP2 and 2 tested positive with only BanMMV CP9. Otherwise, 89 were negative with the two primers and free of flexuous virions. Sanger sequencing was performed from purified PCR products in order to confirm the amplification of the BanMMV sequence for the five accessions with contrasting results. It is highly recommended to use the two primers successively to improve the inclusiveness of the protocol.

Plant vegetative propagation strategies for agricultural crops cause the accumulation of viruses, resulting in the formation of virus complexes or communities. The cultivation of garlic is based on vegetative propagation and more than 13 virus species from the genera Potyvirus, Allexivirus and Carlavirus have been reported. Aiming for an unbiased identification of viruses from a garlic germplasm collection in Brazil, total RNA from eight garlic cultivars was sequenced by high-throughput sequencing (HTS) technology. Although most viruses found in this study were previously reported, one of them did not belong to any known genera. This putative new virus was found in seven out of eight garlic cultivars and phylogenetic data positioned it as representative of an independent evolutionary lineage within family Betaflexiviridae. This virus has been tentatively named garlic yellow mosaic-associated virus (GYMaV), sharing highest nucleotide identities with African oil palm ringspot virus (genus Robigovirus) and potato virus T (genus Tepovirus) for the replicase gene, and with viruses classified within genus Foveavirus for the coat protein gene. Due to its high frequency in garlic cultivars, GYMaV should be considered in upcoming surveys of pathogens in this crop and in the development of virus-free garlic plants.

Plant vegetative propagation strategies for agricultural crops cause the accumulation of viruses, resulting in the formation of virus complexes or communities. The cultivation of garlic is based on vegetative propagation and more than 13 virus species from the genera Potyvirus, Allexivirus and Carlavirus have been reported. Aiming for an unbiased identification of viruses from a garlic germplasm collection in Brazil, total RNA from eight garlic cultivars was sequenced by high-throughput sequencing (HTS) technology. Although most viruses found in this study were previously reported, one of them did not belong to any known genera. This putative new virus was found in seven out of eight garlic cultivars and phylogenetic data positioned it as representative of an independent evolutionary lineage within family Betaflexiviridae. This virus has been tentatively named garlic yellow mosaic-associated virus (GYMaV), sharing highest nucleotide identities with African oil palm ringspot virus (genus Robigovirus) and potato virus T (genus Tepovirus) for the replicase gene, and with viruses classified within genus Foveavirus for the coat protein gene. Due to its high frequency in garlic cultivars, GYMaV should be considered in upcoming surveys of pathogens in this crop and in the development of virus-free garlic plants. [ABSTRACT FROM AUTHOR]

The impact of recombination on variant classification and the use of different genomic regions to identify virus variants were investigated using a diversity study performed on grapevine rupestris stem pitting-associated virus (GRSPaV). Three surveys were conducted to investigate the genetic diversity of GRSPaV and to compare the ability of the GRSPaV coat protein and replicase domains to classify virus variants. GRSPaV variants identified in the surveys clustered into five of the six currently recognised lineages, and a seventh, previously unclassified lineage was detected. A correlation was observed between the detection of recombinant GRSPaV sequences and inconsistencies in classification when using different genome regions for analysis. [ABSTRACT FROM AUTHOR]

Transcriptome data obtained from a plant sample often contain a large number of reads that are derived from associated RNA virus genomes that were co-isolated during RNA preparation. These virusderived reads can be assembled into a novel plant RNA genome sequence. Here, a basil (Ocimum basilicum) transcriptome dataset was analyzed to identify two new RNA viruses, which were named Ocimum basilicum RNA virus 1 (ObRV1) and Ocimum basilicum RNA virus 2 (ObRV2). A phylogenetic analysis of the ObRV1 RNA-dependent RNA polymerase (RdRp) motif indicated that ObRV1 is a novel species of the genus Divavirus of the family Betaflexiviridae. ObRV1 is the fourth divavirus species to be identified. The ObRV2 RdRp motif showed sequence similarity to viruses of the genus Mitovirus of the family Narnaviridae, which infect fungal mitochondria. Although most of the known mitoviruses do not produce a functional RdRp using the plant mitochondrial genetic code, the ObRV2 encodes a full-length RdRp using both the fungal and plant mitochondrial genetic codes. [ABSTRACT FROM AUTHOR]

We report the complete genome sequence of a novel virus, tentatively named “actinidia seed-borne latent virus” (ASbLV), isolated from Actinidia chinensis in Auckland, New Zealand. The complete genome of ASbLV is 8,192 nucleotides long, excluding the 3ʹ poly(A) tail, contains four open reading frames, and is most closely related to Caucasus prunus virus (56% nucleotide sequence identity), a member of the genus Prunevirus. Based on the demarcation criteria of the family Betaflexiviridae, ASbLV is a new member of the genus Prunevirus. [ABSTRACT FROM AUTHOR]

To date, several viruses of different genera have been reported to infect yam (Dioscorea spp.). The full diversity of viruses infecting yam, however, remains to be explored. High-throughput sequencing (HTS) methods are increasingly being used in the discovery of new plant viral genomes. In this study, we employed HTS on yam to determine whether any undiscovered viruses were present that would restrict the international distribution of yam germplasm. We discovered a new virus sequence present in 31 yam samples tested and have tentatively named this virus “yam virus Y” (YVY). Twenty-three of the samples in which YVY was detected showed mosaic and chlorotic leaf symptoms, but Yam mosaic virus was also detected in these samples. Complete genome sequences of two YVY viral isolates were assembled and found to contain five open reading frames (ORFs). ORF1 encodes a large replication-associated protein, ORF2, ORF3 and ORF4 constitute the putative triple gene block proteins, and ORF5 encodes a putative coat protein. Considering the species demarcation criteria of the family Betaflexiviridae, YVY should be considered as a novel virus species in the family Betaflexiviridae. Further work is needed to understand the association of this new virus with any symptoms and yield loss and its implication on virus-free seed yam production.

High throughput sequencing of total RNA isolated from symptomatic leaves of a sweet cherry tree (Prunus avium cv. 0900 Ziraat) from Turkey identified a new member of the genus Robigovirus designated cherry virus Turkey (CVTR). The presence of the virus was confirmed by electron microscopy and overlapping RT-PCR for sequencing its whole-genome. The virus has a ssRNA genome of 8464 nucleotides which encodes five open reading frames (ORFs) and comprises two non-coding regions, 5′ UTR and 3′ UTR of 97 and 296 nt, respectively. Compared to the five most closely related robigoviruses, RdRp, TGB1, TGB2, TGB3 and CP share amino acid identities ranging from 43−53%, 44−60%, 39−43%, 38−44% and 45−50%, respectively. Unlike the four cherry robigoviruses, CVTR lacks ORFs 2a and 5a. Its genome organization is therefore more similar to African oil palm ringspot virus (AOPRV). Using specific primers, the presence of CVTR was confirmed in 15 sweet cherries and two sour cherries out of 156 tested samples collected from three regions in Turkey. Among them, five samples were showing slight chlorotic symptoms on the leaves. It seems that CVTR infects cherry trees with or without eliciting obvious symptoms, but these data should be confirmed by bioassays in woody and possible herbaceous hosts in future studies.

Apple stem grooving virus(ASGV) is the type species of the genusCapillovirusin the familyBetaflexiviridae. The virus naturally infects several important horticultural crops. Although many ASGV isolates from apple (Malusspp.), pear (Pyrusspp.), citrus (Citrusspp.) and lily (Liliumspp.) have been characterized, the occurrence status and molecular characteristics of the virus from kiwifruit trees are still largely unknown. In this study, by employing the strategy of small RNA deep sequencing coupled with conventional RT-PCR, we provide the first complete genome sequence of an ASGV isolate (named ASGV-Ac) infecting a kiwifruit plant (Actinidia chinensis) grown in China. The complete genome of ASGV-Ac consisted of 6496 nucleotides, excluding poly (A) tail at its 3ʹ end. ASGV-Ac shared high nucleotide sequence identities of 96.9% and 93.5% with a kiwifruit ASGV isolate reported from New Zealand (accession no. AF522459) for their CP and MP coding regions. However, the isolate was phylogenetically distal to ASGV isolates from all other hosts by sharing 79.5–82.4% genome sequence identity, and likely represented a novel variant. RT-PCR detection revealed the presence of ASGV-infected kiwifruit in two provinces in China. The partial CP gene of nine ASGV isolates determined in this study shared 87.8–99.6% nucleotide sequence identity with the corresponding sequences of other reported ASGV isolates from kiwifruit, indicating molecular diversity of ASGV isolates from kiwifruit plants. This study provides important evidence for monitoring the viral disease and novel molecular information for developing efficient detection techniques to prevent virus spread. Le virus du bois strié du pommier (VBSP) est l’espèce type du genreCapillovirusde la famille desBetaflexiviridae. Le virus infecte naturellement diverses cultures horticoles d’importance. Bien que plusieurs isolats de VBSP collectés sur les pommiers (Malusspp.), les poiriers (Pyrusspp.), les citrus (Citrusspp.) et les lis (Liliumspp.) aient été caractérisés, les caractéristiques moléculaires et le degré d’occurrence du virus chez le kiwi sont presque totalement inconnus. Dans cette étude, à l’aide du séquençage en profondeur des petits ARN, combiné à une RT-PCR classique, nous fournissons la première séquence génomique complète d’un isolat de VBSP (nommé VBSP-Ac) infectant un plant de kiwi (Actinidia chinensis) cultivé en Chine. Le génome complet de VBSP-Ac était constitué de 6 496 nucléotides, à l’exclusion de la queue poly (A) de l’extrémité 3ʹ. Le VBSP-Ac partageait de fortes identités de séquences de nucléotides de 96.9% et de 93.5% avec un isolat de VBSP de kiwi de Nouvelle-Zélande (n° d’accession AF522459) quant à leurs régions codantes CP et MP. Toutefois, l’isolat était phylogénétiquement distal quant aux isolats de VBSP provenant de tous les autres hôtes, et ce, en partageant de 79.5 à 82.4% de l’identité de la séquence du génome, représentant de toute évidence une nouvelle variante. La détection par RT-PCR a révélé l’occurrence de kiwis infectés par le VBSP dans deux provinces de Chine. Le gène partiel CP de neuf isolats de VBSP identifiés dans le cadre de cette étude partageait de 87.8 à 99.6% de l’identité de la séquence des nucléotides avec les séquences correspondantes d’autres isolats connus de VBSP provenant de kiwis, ce qui met en évidence la diversité moléculaire des isolats de VBSP provenant des plants de kiwi. Cette étude fournit suffisamment de preuves pour inciter à suivre l’évolution de cette maladie virale et amplement d’information moléculaire novatrice pour développer des techniques de détection efficaces visant à prévenir la dissémination du virus. [ABSTRACT FROM AUTHOR]

The present work reports the discovery and the complete genome sequencing of a novel member of the genus Vitivirus in the family Betaflexiviridae (subfamily Trivirinae) from a symptomless grapevine of unknown variety from Portugal. Total RNAs extracted from phloem scrapings were sequenced using Illumina technology. Bioinformatic analysis of the RNA-seq data revealed a mixed infection involving three viruses and two viroids in addition to a novel vitivirus. Completion and analysis of the genome sequence (7446 nt excluding the polyA tail) showed a typical vitivirus genomic organization. Phylogenetic analysis of the various ORFs clearly showed the new virus to belong in the genus Vitivirus, but sequence divergence firmly establishes it as a member of a new species, for which the name ' Grapevine virus H' is proposed. [ABSTRACT FROM AUTHOR]

We report a sequence of a novel vitivirus from Vitis vinifera obtained using two high-throughput sequencing (HTS) strategies on RNA. The initial discovery from small-RNA sequencing was confirmed by HTS of the total RNA and Sanger sequencing. The new virus has a genome structure similar to the one reported for other vitiviruses, with five open reading frames (ORFs) coding for the conserved domains described for members of that genus. Phylogenetic analysis of the complete genome sequence confirmed its affiliation to the genus Vitivirus, with the closest described viruses being grapevine virus E (GVE) and Agave tequilana leaf virus (ATLV). However, the virus we report is distinct and shares only 51% amino acid sequence identity with GVE in the replicase polyprotein and 66.8% amino acid sequence identity with ATLV in the coat protein. This is well below the threshold determined by the ICTV for species demarcation, and we propose that this virus represents a new species. It is provisionally named 'grapevine virus G'. [ABSTRACT FROM AUTHOR]

Cowpea mild mottle virus ( CPMMV) is an emerging severe disease of soybean. The resistant genotypes, DS 12-5 and SL958, were crossed with susceptible genotypes F4C7-32 and JS335, respectively. Resistance reactions of sap-inoculated F2 plants and individual F2 plant-derived F3 families indicated that resistance was controlled by a single dominant gene. Molecular mapping with bulked segregant analysis showed that Satt635 and UO8405 are linked to resistance gene which is located on linkage group H. [ABSTRACT FROM AUTHOR]

Apple stem grooving virus (ASGV), apple chlorotic leaf spot virus (ACLSV), and prunus necrotic ringspot virus (PNRSV) were identified in a crab apple tree by small RNA deep sequencing. The complete genome sequence of ACLSV isolate BJ (ACLSV-BJ) was 7554 nucleotides and shared 67.0%-83.0% nucleotide sequence identity with other ACLSV isolates. A phylogenetic tree based on the complete genome sequence of all available ACLSV isolates showed that ACLSV-BJ clustered with the isolates SY01 from hawthorn, MO5 from apple, and JB, KMS and YH from pear. The complete nucleotide sequence of ASGV-BJ was 6509 nucleotides (nt) long and shared 78.2%-80.7% nucleotide sequence identity with other isolates. ASGV-BJ and the isolate ASGV_kfp clustered together in the phylogenetic tree as an independent clade. Recombination analysis showed that isolate ASGV-BJ was a naturally occurring recombinant. [ABSTRACT FROM AUTHOR]

El cultivo de papa en Colombia es afectado por diversos virus, que incluyen PVY, PLRV, PVX, PMTV y PVS; aunque se han realizado pocos estudios sobre la biología, distribución y patogenicidad de dichos virus en Colombia, siendo especialmente escasa la información referente al PVS. En este trabajo se evaluó mediante pruebas de ELISA, la presencia del PVS en cuatro departamentos de Colombia, así como sus niveles de variación, a partir de la secuenciación de una porción del gen de la cápside viral. Los resultados indicaron una detección promedio del virus en el 40% de las 320 muestras analizadas, con zonas como el Oriente cercano de Antioquia (49%) y Pasto (Nariño) (47%), donde se detectó en mayor proporción el virus. Los análisis de variación molecular indicaron la presencia de las dos razas de PVS (Ordinaria y Andina) en Colombia, siendo los aislamientos de PVS A los más diversos, al pre- sentar un rango de identidad del 88 al 99%. Estos hallazgos indican que es imperativo el fortalecimiento de los programas de certificación de semilla y vigilancia cuarentenaria en el país, especialmente para virus como el PVS, que aunque puede ser asintomático, causa pérdidas hasta del 20% en cultivos de papa.

Apricot latent virus (ApLV) is a definitive species of the Foveavirus genus, the Betaflexiviridae family. Although the virus is not highly prevalent, it was identified in several European and Mediterranean countries thus far. Biological experiments demonstrated that, in addition to the only known natural host, Prunus armeniaca, ApLV can be experimentally graft-transmitted to several Prunus species. Therefore, the eradication of the viral pathogen largely depends on the use of virus-free propagating materials and rootstocks, which should be seriously considered when designing and implementing stone fruit certification schemes. Although ApLV is not present on the list of viruses and other pathogens that require testing in the EPPO certification schemes for the production of healthy stone fruit trees for planting, Peach asteroid spot disease (PAS) causing agent whose occurrence was often justly correlated with ApLV, is included on the list. This review summarises the current available knowledge of ApLV on the biological, morphological, physicochemical and molecular levels and includes the contemporary management approaches.

A novel virus with distinct genome features was discovered by high throughput sequencing in a symptomatic blackcurrant plant. The virus, tentatively named Ribes americanum virus A (RAVA), has distinct genome organization and molecular features bridging genera in the order Tymovirales. The genome consists of 7106 nucleotides excluding the poly(A) tail. Five open reading frames were identified, with the first encoding a putative viral replicase with methyl transferase (MTR), AlkB, helicase, and RNA dependent RNA polymerase (RdRp) domains. The genome organization downstream of the replicase resembles that of members of the order Tymovirales with an unconventional triple gene block (TGB) movement protein arrangement with none of the other four putative proteins exhibiting significant homology to viral proteins. Phylogenetic analysis using replicase conserved motifs loosely placed RAVA within the Betaflexiviridae. Data strongly suggest that RAVA is a novel virus that should be classified as a species in a new genus in the Betaflexiviridae or a new family within the order Tymovirales.

The complete genome sequence of ligustrum virus A (LVA) from a Ligustrum obtusifolium Sieb. & Zucc. plant was determined. The genomic RNA has 8,525 nucleotides, excluding the poly(A) tail, and consists of six open reading frames typical of members of the genus Carlavirus, family Betaflexiviridae. Phylogenetic analysis of the viral replicase and coat protein (CP) indicated that LVA is closely related to daphne virus S and helenium virus. The replicase and CP of LVA shared 44.73-52.35 % and 25.39-62.46 % amino acid identity, respectively, with those of other carlaviruses. These results suggest that LVA is a member of a distinct carlavirus species. [ABSTRACT FROM AUTHOR]

The complete nucleotide sequence of a novel virus from red currant, provisionally named currant virus A (CuVA), was determined. The genome is 7925 nucleotides long and has a 3′-poly(A) tail. The genome organization with two overlapping open reading frames is similar to that of capilloviruses, but the CuVA genome is about 600 nucleotides longer than that of the longest known capillovirus, cherry virus A. The RNA is predicted to encode a polyprotein with domains of methyltransferase, 2OG-Fe(II) oxygenase, papain-like protease, RNA helicase, RdRp, and capsid protein. Phylogenetic analysis confirms that CuVA is a new and distinct member of the genus Capillovirus. [ABSTRACT FROM AUTHOR]

Grapevine Pinot gris virus (GPGV), a member of the genus Trichovirus in the family Betaflexiviridae, was recently discovered in Italy and subsequently in other European countries and in Korea. In this study, we assessed the occurrence of GPGV in 441 samples from Western and Eastern Europe collected over the period 2002-2014. The results suggest that the virus had recently appeared in the Veneto region (Northeast Italy) and had been present in some Eastern European countries for at least 10 years. The molecular characterization of the 5'-terminal genomic region of several GPGV isolates from Italy and other European countries showed low polymorphism, with a maximum nucleotide sequence divergence of 3.2 %. [ABSTRACT FROM AUTHOR]

Double-stranded RNAs purified from cultivated (Lactuca sativa) or wild (L. serriola) lettuce from southwest France were analyzed by high-throughput sequencing. For both samples, BLAST annotation revealed contigs with homology to Betaflexiviridae family members. The full genome sequence of the isolate from cultivated lettuce (JG1) was completed (8,536 nucleotides [nt], excluding the poly(A) tail). The sequence of the 3’ half of the genome (4,800 nt) of a wild lettuce isolate (P22) was determined and found to share 95.1% nt sequence identity with the JG1 isolate. The JG1 genome contains four open reading frames, encoding a replicase, a movement protein, a capsid protein, and a protein of unknown function, respectively. Based on genome organization and phylogenetic relationships, the lettuce virus is most closely related to the recently described carrot chordoviruses 1 and 2 in the family Betaflexiviridae. Considering the species demarcation criteria in this family, the two lettuce viruses represent isolates of a new chordovirus species for which the name “lettuce chordovirus 1” (LeCV1) is proposed. [ABSTRACT FROM AUTHOR]

The complete genome sequence of a member of a distinct species of the genus Carlavirus in the family Betaflexiviridae, tentatively named atractylodes mottle virus (AtrMoV), has been determined. Analysis of its genomic organization indicates that it has a single-stranded, positive-sense genomic RNA of 8866 nucleotides, excluding the poly(A) tail, and consists of six open reading frames typical of members of the genus Carlavirus. The individual open reading frames of AtrMoV show moderately low sequence similarity to those of other carlaviruses at the nucleotide and amino acid sequence levels. Pairwise comparison and phylogenetic analysis suggest that AtrMoV is most closely related to chrysanthemum virus B. [ABSTRACT FROM AUTHOR]