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 journalArticle

4 Citations (Scopus)

Abstract

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
JournalViruses
Volume11
Issue number6
DOIs
Publication statusPublished - Jun 2019

Keywords

  • 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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