Ronan Keener (they/them/theirs)
Graduate Student
University of Minnesota
St. Paul, Minnesota, United States
Matthew Moscou
Research Plant Pathologist
USDA ARS Cereal Disease Laboratory
St Paul, Minnesota, United States
Molly Veregge
Graduate Student
University of Minnesota
St Paul, Minnesota, United States
Kim-Phuong Nguyen
Research Technician
USDA ARS Cereal Disease Laboratory
St Paul, Minnesota, United States
Pablo Olivero-Firpo
Research Plant Pathologist
USDA ARS Cereal Disease Laboratory
St Paul, Minnesota, United States
Robert Alvarez-Quinto
Assistant Professor
University of Minnesota
Minneapolis, Minnesota, United States
Puccinia graminis f. sp. tritici (Pgt), the causal organism of wheat stem rust, is a devastating fungal pathogen infecting cereal crops globally, particularly wheat species. Recently, mycoviruses infecting wheat stripe rust have been associated with increased fungal pathogenicity. However, mycoviruses infecting Pgt have yet to be explored. Here, a mycovirus discovery pipeline was created utilizing Kraken2, Trinity, Transdecoder, BlastX, and HMMSearch to screen for viral sequences in Pgt RNASeq datasets. Total RNA sequencing was conducted utilizing Illumina NovaSeqX on three Pgt samples of US races MCCFC and QFCFC. Additionally, dozens of existing RNA-Seq libraries of different Pgt genetic lineages and geographic origin, including isolates of a distinct sexually recombining population from Spain, were mined for mycoviruses. A wide diversity of viruses was identified within individual samples and across the examined Pgt lineages. Viral genera include Mitovirus, Narnavirus, Totivirus, and recently proposed groups including ormycoviruses and viviviruses. Additionally, numerous viral contigs were identified that have not yet been classified beyond the realm Riboviria. Based on the species demarcation criteria established by the ICTV, nearly all of the viruses presented are novel virus species. These results represent the first virome study for Pgt and show that Pgt hosts diverse viral species across different lineages and geographic regions. Future methods for investigating the biological relevance of these novel viruses will be discussed.