Open AccessAppearance of mycovirus‐like double‐stranded RNA s in the white root rot fungus, R osellinia necatrix , in an apple orchard
Author(s) -
Yaegashi Hajime,
Nakamura Hitoshi,
Sawahata Takuo,
Sasaki Atsuko,
Iwanami Yasuhiko,
Ito Tsutae,
Kanematsu Satoko
Publication year - 2013
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2012.01454.x
Subject(s) - mycovirus , biology , root rot , mycelium , fungus , hypha , botany , microbiology and biotechnology , virology , genetics , rna , gene , rna polymerase
In general, mycoviruses are transmitted through hyphal anastomosis between vegetatively compatible strains of the same fungi, and their entire intracellular life cycle within host fungi limits transmission to separate species and even to incompatible strains belonging to the same species. Based on field observations of the white root rot fungus, Rosellinia necatrix , we found two interesting phenomena concerning mycovirus epidemiology. Specifically, apple trees in an orchard were inoculated with one or two R . necatrix strains that belonged to different mycelial compatibility groups ( MCG s), strains W563 (virus‐free, MCG 139) and NW 10 (carrying a mycovirus‐like double‐stranded (ds) RNA element (N10), MCG 442). Forty‐two sub‐isolates of R . necatrix , which were retrieved 2–3 years later, were all genetically identical to W563 or NW 10: however, 22 of the sub‐isolates contained novel ds RNA s. Six novel ds RNA s (S1‐S6) were isolated: S1 was a new victorivirus; S2, S3, and S4 were new partitiviruses; and S5 and S6 were novel viruses that could not be assigned to any known mycovirus family. N10 ds RNA was detected in three W563 sub‐isolates. These findings indicated that novel mycoviruses, from an unknown source, were infecting strains W563 and NW 10 of R . necatrix in the soil, and that N10 ds RNA was being transmitted between incompatible strains, NW 10 to W563.