Members of the family Secoviridae are non-enveloped plant viruses with mono- or bipartite linear positive-sense ssRNA genomes with a combined genome of 9 to 13.7 kb and icosahedral particles 25-30 nm in diameter. They are related to picornaviruses and are members of the order Picornavirales. Genera in the family are distinguished by the host range, vector, genomic features and phylogeny of the member viruses. Most members infect dicotyledonous plants, and many cause serious disease epidemics. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) report on the family Secoviridae, which is available at ictv.global/report/secoviridae.

• Klíčová slova
• ICTV report, Secoviridae, taxonomy,
• MeSH
• fylogeneze MeSH
• genom virový MeSH
• replikace viru MeSH
• RNA-viry * genetika   MeSH
• rostliny MeSH
• Secoviridae * genetika   MeSH
• virion genetika   MeSH
• viry * genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Members of the family Pospiviroidae have single-stranded circular RNA genomes that adopt a rod-like or a quasi-rod-like conformation. These genomes contain a central conserved region that is involved in replication in the nucleus through an asymmetric RNA-RNA rolling-circle mechanism. Members of the family Pospiviroidae lack the hammerhead ribozymes that are typical of viroids classified in the family Avsunviroidae. The family Pospiviroidae includes the genera Apscaviroid, Cocadviroid, Coleviroid, Hostuviroid and Pospiviroid, with >25 species. This is a summary of the ICTV Report on the family Pospiviroidae, which is available at ictv.global/report/pospiviroidae.

• Klíčová slova
• ICTV Report, Pospiviroidae, taxonomy,
• MeSH
• genom virový MeSH
• kruhová RNA MeSH
• replikace viru * MeSH
• RNA katalytická genetika   MeSH
• RNA virová genetika   MeSH
• RNA genetika   MeSH
• viroidy klasifikace   genetika   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• hammerhead ribozyme MeSH Prohlížeč
• kruhová RNA MeSH
• RNA katalytická MeSH
• RNA virová MeSH
• RNA MeSH

The Hypoviridae, comprising one genus, Hypovirus, is a family of capsidless viruses with positive-sense, ssRNA genomes of 9.1-12.7 kb that possess either a single large ORF or two ORFs. The ORFs appear to be translated from genomic RNA by non-canonical mechanisms, i.e. internal ribosome entry site-mediated and stop/restart translation. Hypoviruses have been detected in ascomycetous or basidiomycetous filamentous fungi, and are considered to be replicated in host Golgi-derived, lipid vesicles that contain their dsRNA as a replicative form. Some hypoviruses induce hypovirulence to host fungi, while others do not. This is a summary of the current ICTV report on the taxonomy of the Hypoviridae, which is available at www.ictv.global/report/hypoviridae.

• Klíčová slova
• Hypoviridae, ICTV Report, Taxonomy,
• MeSH
• dvouvláknová RNA genetika   MeSH
• fylogeneze MeSH
• genom virový MeSH
• houby virologie   MeSH
• otevřené čtecí rámce MeSH
• RNA virová genetika   MeSH
• RNA-viry klasifikace   genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• dvouvláknová RNA MeSH
• RNA virová MeSH

Members of the family Pleolipoviridae (termed pleolipoviruses) are pseudo-spherical and pleomorphic archaeal viruses. The enveloped virion is a simple membrane vesicle, which encloses different types of DNA genomes of approximately 7-16 kbp (or kilonucleotides). Typically, virions contain a single type of transmembrane (spike) protein at the envelope and a single type of membrane protein, which is embedded in the envelope and located in the internal side of the membrane. All viruses infect extremely halophilic archaea in the class Halobacteria (phylum Euryarchaeota). Pleolipoviruses have a narrow host range and a persistent, non-lytic life cycle. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Pleolipoviridae which is available at www.ictv.global/report/pleolipoviridae.

• Klíčová slova
• Halorubrum pleomorphic virus 1, ICTV, Pleolipoviridae, taxonomy,
• MeSH
• fyziologie virů MeSH
• genom virový MeSH
• hostitelská specificita MeSH
• virové proteiny genetika   metabolismus   MeSH
• viry klasifikace   genetika   izolace a purifikace   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• virové proteiny MeSH

Members of the family Avsunviroidae have a single-stranded circular RNA genome that adopts a rod-like or branched conformation and can form, in the strands of either polarity, hammerhead ribozymes involved in their replication in plastids through a symmetrical RNA-RNA rolling-circle mechanism. These viroids lack the central conserved region typical of members of the family Pospiviroidae. The family Avsunviroidae includes three genera, Avsunviroid, Pelamoviroid and Elaviroid, with a total of four species. This is a summary of the ICTV Report on the taxonomy of the family Avsunviroidae, which is available at http://www.ictv.global/report/avsunviroidae.

• Klíčová slova
• Avsunviroidae, ICTV, avocado sunblotch viroid, eggplant latent viroid, peach latent mosaic viroid, taxonomy, viroid,
• MeSH
• genom virový MeSH
• kruhová RNA MeSH
• replikace DNA MeSH
• replikace viru * MeSH
• RNA katalytická genetika   MeSH
• RNA virová genetika   MeSH
• RNA genetika   MeSH
• viroidy klasifikace   genetika   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• hammerhead ribozyme MeSH Prohlížeč
• kruhová RNA MeSH
• RNA katalytická MeSH
• RNA virová MeSH
• RNA MeSH

Members of the family Secoviridae are non-enveloped viruses with mono- or bipartite (RNA-1 and RNA-2) linear positive-sense ssRNA genomes with the size of the RNAs combined ranging from 9 to 13.7 kb. They are related to picornaviruses and are classified in the order Picornavirales. The majority of known members infect dicotyledonous plants and many are important plant pathogens (e.g. grapevine fanleaf virus and rice tungro spherical virus). This is a summary of the current International Committee on Taxonomy of Viruses (ICTV) report on the taxonomy of the family Secoviridae available at www.ictv.global/report/secoviridae.

• MeSH
• RNA virová genetika   MeSH
• RNA-viry klasifikace   genetika   MeSH
• rostlinné viry klasifikace   genetika   MeSH
• rostliny virologie   MeSH
• virové nemoci virologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• RNA virová MeSH

Bromoviridae is a family of plant viruses with tripartite, positive-sense RNA genomes of about 8 kb in total. Genomic RNAs are packaged in separate virions that may also contain sub-genomic, defective or satellite RNAs. Virions are variable in morphology (spherical or bacilliform) and may be transmitted between hosts mechanically, via pollen, or non-persistently by insect vectors. Members of the family are responsible for major disease epidemics in fruit, vegetable and fodder crops such as tomatoes, cucurbits, bananas, fruit trees, common beans and alfalfa. Since the adoption of metagenomic high-throughput sequencing methodologies, there has been a notable increase in the number of species in the genus Ilarvirus. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the family Bromoviridae, which is available at ictv.global/report/bromoviridae.

• Klíčová slova
• Bromoviridae, ICTV Report, taxonomy,
• MeSH
• Bromoviridae * klasifikace   genetika   izolace a purifikace   ultrastruktura   MeSH
• fylogeneze MeSH
• genom virový MeSH
• nemoci rostlin * virologie   MeSH
• RNA virová genetika   MeSH
• rostlinné viry * klasifikace   genetika   MeSH
• virion genetika   ultrastruktura   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• RNA virová MeSH

Barley yellow dwarf disease, a ubiquitous virus disease of cereal crops worldwide, is caused by a group of related, single-stranded RNA viruses assigned to Luteovirus (Barley yellow dwarf virus [BYDV] spp. PAV, PAS, MAV, and GAV) or Polerovirus (Cereal yellow dwarf virus-RPV) genera or unassigned to a genera (BYDV-SGV, BYDV-RMV, and BYDV-GPV) in the family Luteoviridae (1). Incidence of BYDV in cereal crops (e.g., barley, wheat, and oats) was high, and in recent years, reached epidemic levels in many regions of the Czech Republic. BYDV-PAV and BYDV-PAS have been identified in Czech cereal crops (2,4). Surveys of the incidence of BYDV were carried out using ELISA (SEDIAG SAS, Longvic, France) and one-step reverse transcription (RT)-PCR (Qiagen, Hilden, Germany) (2) during 2007 and 2008. Samples (125) were collected from different fields around the Czech Republic and 96 were BYDV positive. Three of the field isolates, CZ-6815, CZ-1561, and CZ-10844, from oat (Avena sativa; cv. Auron), winter wheat (Triticum aestivum; cv. Apache), and winter barley (Hordeum vulgare; cv. Merlot), respectively, were identified as BYDV-MAV by sequencing of the RT-PCR product (641-bp fragment) used to identify BYDV, which spanned 2839-3479 of the BYDV genome (GenBank Accession Nos. EF043235 and NC_002160) (2). The partial coat protein gene sequence of 483 nt was compared with the available sequences of 12 BYDV-PAV isolates (PAV-JP, PAV-NY, PAV-ILL, PAV-AUS, PAV-WG2, PAV-whG4y3, PAV-on21-4, Tahoe1, CA-PAV, HB3, FH3, and MA9501); nine BYDV-PAS isolates (PAS-129, PAS-64, WS6603, WG13, PAS-Tcb4-1, PASwaw5-9, FL2, PAS-Vd29, and PAS-MA9516); and six BYDV-MAV isolates (MAV-CA, MAV-PS1X1, MAV-Alameds268, LMB2a, SI-o4, and MAV-CN) by MEGA4 (3). Nucleotide and amino acid sequence identities for the three isolates ranged from 92.9 to 99.4% and 88.0 to 95.8%, respectively, for available BYDV-MAV isolates; 76.8 to 78.2% and 62.7 to 67.6%, respectively, for available BYDV-PAS isolates; and 77.6 to 79.3% and 65.5 to 70.4%, respectively, for available PAV isolates. The sequence data indicates that these isolates (CZ-6815, CZ-1561, and CZ10844; GenBank Accession Nos. FJ645747, FJ645758, and FJ645746, respectively) are BYDV-MAV. To my knowledge, this is the first record of BYDV-MAV in the Czech Republic. References: (1) C. J. D'Arcy and L. L. Domier. Page 891 in: Virus Taxonomy-8th Report of the ICTV. C. M. Fauquet et al., eds. Springer-Verlag, NY, 2005. (2) J. K. Kundu. Plant Dis. 92:1587, 2008. (3) K. Tamura et al. Mol. Biol. Evol. 24:1596, 2007. (4) J. Vacke. Page 100 in: Sbornik Referatu z Odborneho Seminare, Aktualni Problemy Ochrany Polnich Plodin, Praha, 1991.

• Publikační typ
• časopisecké články MeSH

Barley yellow dwarf disease, an important, ubiquitous virus disease of cereal crops worldwide, is caused by a group of related single-stranded RNA viruses assigned to luteovirus (Barley yellow dwarf virus (BYDV) spp. PAV, PAS, MAV, and GAV) or polerovirus (Cereal yellow dwarf virus-RPV) genera or unassigned to a genera (BYDV-SGV, BYDV-RMV, and BYDV-GPV) in the family Luteoviridae (2). Incidence of BYDV in cereal crops (e.g., barley, wheat, and oats) was high and reached epidemic levels in recent years in many regions of the Czech Republic. Previously, only PAV isolates have been identified here on the basis of serological detection (4), although antibodies to differentiate between PAV, PAS, and MAV are not widely available. Field samples of cereal crops were routinely tested in 2006 and 2007 and BYDVs were detected by ELISA. One-step-reverse transcription (RT)-PCR (Qiagen, Hilden, Germany) was adapted for BYDV detection using primer pairs BYcpF (5'-CCACTAGAGAGGTGGTGAATG-3') and BYcpR (5'-CCGGTGTTGAGGAGTCTACC-3') designed from conserved sequences identified by aligning multiple BYDV sequences available in public databases. These primers amplify a 641-bp fragment spanning nucleotides 2839-3479 from PAV (GenBank Accession No. EF043235) or PAS (GenBank Accession No. NC_002160) that includes a region of the coat protein gene and the intergenic region. RT-PCR amplicons were generated from two field isolates, PS-RuJK (spring wheat isolate, cv. Granny, collected in July 2007 from experimental plots at the CRI in Prague) and JE-120JK (winter barley isolate, cv. Merlot, collected in January 2008 from a barley field in Rychnov), both of which induced severe BYD symptoms. Amplicons were sequenced in both directions in a CEQ2000XL sequencer (Beckman Coulter, Fullerton, CA). The partial coat protein gene sequence of 483 nt of PS-RuJK and JE-120JK was analyzed and compared with available sequences of 26 PAV, 17 PAS, and 13 MAV isolates by MEGA4 (3). PS-RuJK (GenBank Accession No. EU863652) nucleotide and amino acid sequence identities ranged from 96.3 to 99.2% and 93.7 to 98.7%, respectively, for available PAS isolates, and 89.9 to 90.5% and 85.5 to 86.9%, respectively, for available PAV isolates, and 78.3 to 79.5% and 70.0 to 72.5%, respectively, for available MAV isolates. Similarly, nucleotide and amino acid sequence identities JE-120JK (GenBank Accession No. EU863653) ranged from 95.2 to 98.6% and 90.6 to 96.9%, respectively, for PAS isolates, 88.8 to 90.1% and 83.1 to 84.4%, respectively, for PAV isolates, and 77.6 to 78.7% and 67.5 to 70.0%, respectively, for MAV isolates. Also, both of these isolates have the conserved amino acid motif "SIPGS" that is usually present in a variable region of the coat protein gene on the surface of virion (1) at position 52 to 56 of amino acid sequences of all published PAS-like isolates, including Vd29:AY167109, FH1:AJ223588, MA9516:AJ007926, FL2:AJ223586, ASL-1:AJ810418, and WS6603:DQ285680, contrary to "PVFRP" or "LISGP" motif in PAV or MAV, respectively. Therefore, the sequence data clearly confirm that these two isolates belong to the PAS species. To our knowledge, this is the first record of PAS detected in the Czech Republic. References: (1) C. A. Chay et al. Phytopathology 86:370, 1996. (2) C. J. D'Arcy and L. L. Domier. Page 891 in: Virus Taxonomy-8th Report of the ICTV. C. M. Fauquet et al., eds. Springer-Verlag, NY, 2005. (3) K. Tamura et al. Mol. Biol. Evol. 24:1596, 2007. (4) J. Vacke. Page 100 in: Sbornik Referatu z Odborneho Seminare, Aktualni Problemy Ochrany Polnich Plodin. Praha, 1991.

• Publikační typ
• časopisecké články MeSH