Novel victorivirus from a pakistani isolate of alternaria alternata lacking a typical translational stop/restart sequence signature

Atif Jamal, Yukiyo Sato, Sabitree Shahi, Wajeeha Shamsi, Hideki Kondo, Nobuhiro Suzuki

    Research output: Contribution to journalArticlepeer-review

    9 Citations (Scopus)


    The family Totiviridae currently contains five genera Totivirus, Victorivirus, Leishmavirus, Trichomonasvirus, and Giardiavirus. Members in this family generally have a set of two-open reading frame (ORF) elements in their genome with the 5’-proximalORF (ORF1) encoding a capsid protein (CP) and the 3’-proximal one (ORF2) for RNA-dependent RNA polymerase (RdRp). How the downstream open reading frames (ORFs) are expressed is genus-specific. All victoriviruses characterized thus far appear to use the stop/restart translation mechanism, allowing for the expression of two separate protein products from bicitronic genome-sized viral mRNA, while the totiviruses use a -1 ribosomal frame-shifting that leads to a fusion product of CP and RdRp. We report the biological and molecular characterization of a novel victorivirus termed Alternaria alternata victorivirus 1 (AalVV1) isolated from Alternaria alternata in Pakistan. The phylogenetic and molecular analyses showed AalVV1 to be distinct from previously reported victoriviruses. AalVV1 appears to have a sequence signature required for the -1 frame-shifting at the ORF1/2 junction region, rather than a stop/restart key mediator. By contrast, SDS–polyacrylamide gel electrophoresis and peptide mass fingerprinting analyses of purified virion preparations suggested the expression of two protein products, not a CP-RdRp fusion product. How these proteins are expressed is discussed in this study. Possible effects of infection by this virus were tested in two fungal species: A. alternata and RNA silencing proficient and deficient strains of Cryphonectria parasitica, a model filamentous fungus. AalVV1 showed symptomless infection in all of these fungal strains, even in the RNA silencing deficient C. parasitica strain.

    Original languageEnglish
    Article number577
    Issue number6
    Publication statusPublished - Jun 2019


    • Alternaria alternata
    • Cryphonectria parasitica
    • DsRNA
    • Indian subcontinent
    • Mycovirus
    • Pseudoknot structure
    • Stop/restart translation
    • Totiviridae
    • Victorivirus

    ASJC Scopus subject areas

    • Infectious Diseases
    • Virology


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