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Citrus yellow-vein disease (CYVD) was first reported in California in 1957. We now report that CYVD is associated with a virus-like agent, provisionally named citrus yellow-vein associated virus (CYVaV). The CYVaV RNA genome has 2,692 nucleotides and codes for two discernable open reading frames (ORFs). ORF1 encodes a protein of 190 amino acid (aa) whereas ORF2 is presumably generated by a -1 ribosomal frameshifting event just upstream of the ORF1 termination signal. The frameshift product (717 aa) encodes the RNA-dependent RNA polymerase (RdRp). Phylogenetic analyses suggest that CYVaV is closely related to unclassified virus-like RNAs in the family Tombusviridae. Bio-indexing and RNA-seq experiments indicate that CYVaV can induce yellow vein symptoms independently of known citrus viruses or viroids.

The invasive soybean aphid, Aphis glycines, is a major pest in soybeans, resulting in substantial economic loss. We analyzed the A. glycines transcriptome to identify sequences derived from viruses of A. glycines. We identified sequences derived from a novel virus named Aphis glycines virus 2 (ApGlV2). The assembled virus genome sequence was confirmed by reverse transcription polymerase chain reaction (RT-PCR) and Sanger sequencing, conserved domains were characterized, and distribution, and transmission examined. This virus has a positive sense, single-stranded RNA genome of ~4850 nt that encodes three proteins. The RNA-dependent RNA polymerase (RdRp) of ApGlV2 is a permuted RdRp similar to those of some tetraviruses, while the capsid protein is structurally similar to the capsid proteins of plant sobemoviruses. ApGlV2 also encodes a larger minor capsid protein, which is translated by a readthrough mechanism. ApGlV2 appears to be widespread in A. glycines populations and to persistently infect aphids with a 100% vertical transmission rate. ApGlV2 is susceptible to the antiviral RNA interference (RNAi) pathway. This virus, with its unique genome structure with both plant- and insect-virus characteristics, is of particular interest from an evolutionary standpoint. [ABSTRACT FROM AUTHOR]

Abstract: A small isometric virus has been isolated from larvae of the Guatemala potato tuber moth, Tecia solanivora (Povolny), collected in Ecuador. It was designated the Anchilibi virus (AnchV). The non-enveloped viral particles have an estimated diameter of 32±2nm. Three major proteins were found in virions, with estimated sizes of 102.0±2.1, 95.8±2.0 and 92.4±1.5kDa for AnchV as determined by polyacrylamide gel electrophoresis. After denaturing agarose gel electrophoresis, the genome of AnchV appeared to be a tri-segmented single-stranded RNA with fragment sizes of 4.1±0.2, 2.8±0.2 and 1.65±0.2kb. In addition to a high virulence towards its original host, AnchV also caused high mortality in larvae of two other potato tuber moth species, Phthorimaea operculella (Zeller) and Symmetrischema (tangolias) plaesiosema (Turner). Electron microscopy confirmed that AnchV replication occurs in the cell cytoplasm, mainly in vesicles. Several important characteristics exhibited by this virus differ from those reported for known families of insect viruses. Thus, AnchV might be member of a new taxonomic group. [Copyright &y& Elsevier]

Citrus yellow-vein disease (CYVD) was first reported in California in 1957. We now report that CYVD is associated with a virus-like agent, provisionally named citrus yellow-vein associated virus (CYVaV). The CYVaV RNA genome has 2,692 nucleotides and codes for two discernable open reading frames (ORFs). ORF1 encodes a protein of 190 amino acid (aa) whereas ORF2 is presumably generated by a -1 ribosomal frameshifting event just upstream of the ORF1 termination signal. The frameshift product (717 aa) encodes the RNA-dependent RNA polymerase (RdRp). Phylogenetic analyses suggest that CYVaV is closely related to unclassified virus-like RNAs in the family Tombusviridae . Bio-indexing and RNA-seq experiments indicate that CYVaV can induce yellow vein symptoms independently of known citrus viruses or viroids., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Kwon, Bodaghi, Dang, Gadhave, Ho, Osman, Al Rwahnih, Tzanetakis, Simon and Vidalakis.)