Abstract
Characterization of newly isolated mycoviruses may contribute to understanding of the evolution and diversity of viruses. Here, a deep sequencing approach was used to analyze the double-stranded RNA (dsRNA) mycoviruses isolated from field-collected P. striiformis samples in China. Database searches showed the presence of at least four totivirus-like sequences, termed Puccinia striiformis virus 1 to 4 (PsV1 to 4). All of these identified sequences contained two overlapping open reading frames (ORFs) which encode a putative coat protein (CP) and an RNA-dependent RNA polymerase (RdRp) showing similar structures to members of the genus Totivirus. Each PsV contained a -1 ribosomal frameshifting region with a slippery site and a pseudoknot structure in the overlapped regions of these ORFs, indicating that the RdRp is translated as a CP-RdRp fusion. Phylogenetic analyses based on RdRp and CP suggested that these novel viruses belong to the genus Totivirus in the family Totiviridae. The presences of these PsVs were further validated by transmission electron microscope (TEM) and RT-PCR. Taken together, our results demonstrate the presence of diverse, novel totiviruses in the P. striiformis field populations.
Highlights
Mycoviruses are of common occurrence in all major taxonomic groups of filamentous fungi, yeasts and oomycetes (Pearson et al, 2009; Ghabrial et al, 2015)
Some progress has been made in obtaining double-stranded RNA (dsRNA) from rust mycoviruses, little is known about their genome organization, which is due in a large extent to their asymptomatic infections (Zhang et al, 1994)
Four P. striiformis-derived totivirus-like sequences, termed as Puccinia striiformis virus 1 to 4 (PsV1 to 4) (Supplementary Table S2), were identified from the post-assembly contigs by deep sequencing
Summary
Mycoviruses (fungal viruses) are of common occurrence in all major taxonomic groups of filamentous fungi, yeasts and oomycetes (Pearson et al, 2009; Ghabrial et al, 2015). The family Totiviridae currently comprises five approved genera, of which totiviruses and victoriviruses infect only fungi, while giardiaviruses, trichomonasviruses and leishmaniaviruses infect mainly protozoa (Goodman et al, 2011; Kondo et al, 2016). Members of this family have nonsegmented dsRNA genomes being 4.6–7.0 kbp in length and usually contain two large, partially overlapping open reading frames (ORFs) which encode a capsid protein (CP) and an RNAdependent RNA polymerase (RdRp) respectively (Ghabrial et al, 2015)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
