Detection and characterization of DNA plasmids from the shiitake mushroom, Lentinula edodes

本研究旨在探讨DNA质粒与香菇(Lentinula edodes(Berk.)Pegler和描述它们的一般性质。对1株双核菌和11株双核菌(90株采自不同工作地区的天然菌株和21株商品菌株)进行了质粒检测。大约80%的受试者被确定为获得一种或多种不同类型的DNA质粒。检测到6种pLE1(9.0kb)、pLE2(11.1kb)、pLE3A(9.8kb)、pLE3B(10.8kb)、pLE3c(12.1kb)和pLE3D(12.3kb)，杂交分析表明，pLE1和pLE2是不同同源类群的不同质粒型，其余4种为不同同源类群的变异型。这些质粒中的任何一个与宿主和非宿主的核和线粒体基因组DNA没有同源性。限制性内切酶分析和电子显微镜观察表明，它们在形式上是线性的。由于这6个质粒在有性杂交中都是单亲传递的，因此建议它们定位在细胞质中。从香菇自然种群中6个质粒的分布来看，pLE1和pLE2在地理上分布广泛，而其他4个质粒在地理上不同的自然种群中的分布是唯一的。从质粒的地理分布格局推测，香菇的原产地在南太平洋。

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.