Identification and genetic characterization of a new totivirus from Bursera graveolens in western Ecuador

Molecular characterization of birch toti-like virus, a plant-associated member of the new family Orthototiviridae

A novel totivirus, named "birch toti-like virus" (BTLV), was discovered in European white birch (Betula pendula) plants. The genome of BTLV is 4,967 nucleotides long and contains two overlapping open reading frames (ORFs) coding for the capsid protein (CP) and an RNA-dependent RNA-polymerase (RdRP). The encoded CP and RdRP proteins shared 46.9% and 60.2% amino acid sequence identity, respectively, with those of Panax notoginseng virus B. The presence of a putative slippery heptamer signal 82 nt upstream of the stop codon of ORF1 suggests that a -1 translational frameshifting strategy is involved in the expression of ORF2, like in other totiviruses. Phylogenetic analysis based on the CP and RdRP amino acid sequences placed this virus within a clade of plant-associated totiviruses, with taro-associated virus as its closest relative. Hence, based on its distinct host and the amino acid sequence similarity between BTLV and its relatives, we conclude that birch toti-like virus is a new member of the genus Totivirus.

Complete genome sequence of vaccinium-associated virus C, a new member of the family Totiviridae from Vaccinium floribundum

Blueberries (Vaccinium sp.) are a major crop grown in the Pacific Northwest region. Currently, there are at least 17 known viruses that infect blueberry plants, and some of them cause a wide range of symptoms and economic losses. A new virus, vaccinium-associated virus C (VaVC) (family Totiviridae, genus Totivirus) was identified in an imported blueberry accession from the USDA-ARS National Clonal Germplasm Repository in Corvallis, Oregon. The complete genomic sequence of VaVC was determined, but the biological significance of VaVC is unknown and requires further study. Additional Vaccinium sp. accessions should be screened to investigate the incidence of this new virus.

Transcriptome Analysis Reveals a Diverse Range of Novel Viruses in Australian Sugarcane Soldier Fly (Inopus flavus) Larvae

In Australia, Soldier flies (Inopus spp.) are economically significant pests of sugarcane that currently lack a viable management strategy. Despite various research efforts, the mechanisms underlying the damage caused by soldier fly larvae remain poorly understood. Our study aims to explore whether this damage is associated with the transmission of plant viruses during larval feeding. We also explore the larval transcriptome to identify any entomopathogenic viruses with the potential to be used as biocontrol agents in future pest management programs. Seven novel virus sequences are identified and characterised using de novo assembly of RNA-Seq data obtained from salivary glands of larvae. The novel virus sequences belong to different virus families and are tentatively named SF-associated anphevirus (SFaAV), SF-associated orthomyxo-like virus (SFaOV), SF-associated narna-like virus (SFaNV), SF-associated partiti-like virus (SFaPV), SF-associated toti-like virus (SFaTV-1 and SFaTV-2) and SF-associated densovirus (SFaDV). These newly identified viruses are more likely insect-associated viruses, as phylogenetic analyses show that they cluster with other insect-specific viruses. Small RNA analysis indicates prominent peaks at both 21 nt and 26-29 nt, suggesting the activation of host siRNA and piwiRNA pathways. Our study helps to improve understanding of the virome of soldier flies and could identify insect viruses for deployment in novel pest management strategies.

Identification and molecular characterization of a novel totivirus from Mangifera indica

In this study, we determined the complete genome sequence of a novel totivirus, tentatively named "Mangifera indica totivirus 1" (MiTV1), identified in 'Apple' mango in China. The double-stranded RNA genome of MiTV1 is 4800 base pairs (bp) in length and contains two open reading frames (ORFs) encoding a putative coat protein (CP) and an RNA-dependent RNA polymerase (RdRp). Phylogenetic analysis based on RdRp and CP amino acid sequences showed that MiTV1 is closely related to members of the genus Totivirus in the family Totiviridae. To our knowledge, this is the first report of a totivirus found in Mangifera indica.