|Budget Amount *help
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1996: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1995: ¥1,200,000 (Direct Cost: ¥1,200,000)
The aim of this study is to examine the association of DNA plasmids with the shiitake mushroom, Lentinula edodes (Berk.) Pegler and to describe their general properties. A survey of a total of one hndred and eleven dikaryotic strains (ninety natral isolates collected from geographically different workd regions and twenty-one commercial strains) for the presence of plasmids was carried out. About 80% of thesestrains employed were determined to harvor one or more different kinds of DNA plasmids. The plasmids detected were the six kinds of designated pLE1 (9.0kb) , pLE2 (11.1kb) , pLE3A (9.8kb) , pLE3B (10.8kb) , pLE3C (12.1kb) , and pLE3D (12.3kb) .Based on hybridization analysis, it was suggested that pLE1 and pLE2 were distinct plasmid types of different homology groups to each other, and the remaining four kinds of plasmids were variant types belonging to another, the third, common hoology group. Any of such plasmids gave no homology with their host's and non-host's nuclear and mitochondrial genome DNAs. Restriction analysis and electron microscopy on these plasmids indicated that they are linear in form. Since all of the six plasmids were transmitted uniparentally in sexual crosses, they were suggested to locate in cytoplasm. Considering the distribution of the six plasmids in natural populations of L.edodes, pLE1 and pLE2 each were known to show geographically wide distribution, but the other four plasmids were present to be uniqe for each of geographically distinct natural populations. From the geographical distribution pattern of plasmids, it was presumed that the ancestral area for shiitake mushroom is in the South Pacific.