open access

https://hdl.handle.net/2115/49461

A novel virus-like double-stranded RNA in an obligate biotroph arbuscular mycorrhizal fungus: a hidden player in mycorrhizal symbiosis

英語

2012

APS Press

Molecular Plant-Microbe Interactions

25(7)

120314052115002

Arbuscular mycorrhizal (AM) fungi form mutualistic associations with most land plants and enhance phosphorus uptake of the host plants. Fungal viruses (mycoviruses) that possess a double-stranded RNA (dsRNA) genome often impact on plant-fungal interactions via altering phenotypic expression of their host fungi. The present study for the first time demonstrates the presence of dsRNAs, which is highly likely to be mycoviruses, in AM fungi. dsRNA was extracted from mycelia of Glomus sp. RF1, purified, and subjected to electrophoresis. The fungus was found to harbor various dsRNA segments that differed in size. Among them, a 4.5-kbp segment was termed Glomus sp. RF1 virus-like-medium dsRNA (GRF1V-M) and characterized in detail. The GRF1V-M genome segment was 4,557 nucleotides in length and encoded RNA-dependent RNA polymerase and a structural protein. GRF1V-M was phylogenetically distinct and could not be assigned to known genera of mycovirus. The GRF1V-M-free culture line of Glomus sp. RF1, which was raised by single spore isolation, produced two-fold greater number of spores and promoted plant growth more efficiently than the GRF1V-M-positive lines. These observations suggest that mycoviruses in AM fungi, at least some of them, have evolved under unique selection pressures and are a biologically active component in the symbiosis.

学術雑誌論文

Accepted Manuscript

0894-0282