title: Characterization of Five Novel Mitoviruses in the White Pine Blister Rust Fungus Cronartium ribicola.
abstract: The white pine blister rust (WPBR) fungus Cronartium ribicola (J.C. Fisch.) is an exotic invasive forest pathogen causing severe stem canker disease of native white pine trees (subgenus Strobus) in North America. The present study reports discovery of five novel mitoviruses in C. ribicola by deep RNA sequencing. The complete genome of each mitovirus was determined by rapid amplification of cDNA ends (RACE) and reverse transcriptase-polymerase chain reaction (RT-PCR). A single open reading frame (ORF) encoding a putative RNA-dependent RNA polymerase (RdRp) was detected in each of the viral genomes using mitochondrial genetic codes. Phylogenetic analysis indicated that the C. ribicola mitoviruses (CrMV1 to CrMV5) are new putative species of the genus Mitovirus. qRT-PCR and RNA-Seq analyses revealed that viral RNAs were significantly increased in fungal mycelia in cankered pine stems compared to expression during two different stages of spore development, suggesting that viral genome replication and transcription benefit from active growth of the host fungus. CrMVs were widespread with relatively high levels of minor allele frequency (MAF) in western North America. As the first report of mitoviruses in the Class Pucciniomycetes, this work allows further investigation of the dynamics of a viral community in the WPBR pathosystem, including potential impacts that may affect pathogenicity and virulence of the host fungus.
authors.affiliation: Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, Victoria, BC, V8Z 1M5, Canada.
authors.forename: Jun-Jun
authors.initials: JJ
authors.lastname: Liu
authors.affiliation: Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, Victoria, BC, V8Z 1M5, Canada.
authors.forename: Danelle
authors.initials: D
authors.lastname: Chan
authors.affiliation: Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, BC, V0H 1Z0, Canada.
authors.forename: Yu
authors.initials: Y
authors.lastname: Xiang
authors.affiliation: Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, Victoria, BC, V8Z 1M5, Canada.
authors.forename: Holly
authors.initials: H
authors.lastname: Williams
authors.affiliation: Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, Victoria, BC, V8Z 1M5, Canada.
authors.forename: Xiao-Rui
authors.initials: XR
authors.lastname: Li
authors.affiliation: USDA Forest Service, Dorena Genetic Resource Center, Cottage Grove, Oregon, 97424, United States of America.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Sniezko
authors.affiliation: Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, Victoria, BC, V8Z 1M5, Canada.
authors.forename: Rona N
authors.initials: RN
authors.lastname: Sturrock
mesh_terms: D000483:Alleles; D001487:Basidiomycota / Q000821:virology*; D018076:DNA, Complementary / Q000032:analysis; D014644:Genetic Variation; D016679:Genome, Viral; D009690:Nucleic Acid Conformation; D016366:Open Reading Frames; D010802:Phylogeny; D028223:Pinus / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology*; D018547:Plant Stems / Q000382:microbiology; D012328:RNA Viruses / Q000145:classification / Q000302:isolation & purification*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017423:Sequence Analysis, RNA; D059467:Transcriptome
chemical_list: D018076:DNA, Complementary