Detection and distribution of six linear mitochondrial plasmids in the shiitake mushroom, Lentinula edodes

Abstract

The presence of plasmids was surveyed in 90 wild isolates of Lentinula edodes collected from geographically different world regions. DNA plasmids of different sizes were found in about 80% of the isolates. The plasmids detected were of six kinds, designated as pLE1 (9.0 kb), pLE2 (11.1 kb, =pLLE1 described by other authors), pLE3A (9.8 kb), pLE3B (10.8 kb), pLE3C (12.1 kb), and pLE3D (12.3 kb). Hybridization analysis suggested that pLE1 and pLE2 were distinct plasmid types of different homology groups to each other, and the four other plasmids were variant types belonging to a third homology group. These plasmids had no homology with their host's and non-host's nuclear and mitochondrial genome DNAs. Restriction analysis and electron microscopy indicated that the plasmids are linear in form. Since all six plasmids were transmitted uniparentally in sexual crosses and were consistently associated with the DNA preparations from mitochondria fractionated from mycelia of representative isolates, they were suggested to be located in mitochondria, similar to many other known fungal DNA plasmids. Geographically, pLE1 and pLE2 were widely distributed in natural populations of L. edodes, while the remaining four plasmids were uniquely present in delimited natural populations.

Transmission of mitochondrial plasmids in protoplast cell fusion between compatible monokaryons of Lentinula edodes

“…3). Among these bands, the 6.5 and 4.6 kb bands were accordance with those from pLE2, and the remaining three bands from pLE3C, as reported by Fukumasa-Nakai et al 3 The BamHI digestion pattern of pLE3D from 1569a, which consists three restriction bands of 5.8, 3.8 and 2.7 kb (Fig. 3), was identical to published results.…”

“…3), was identical to published results. 3 Thus, pLE3C and pLE3D could be distinguished from each other by BamHI digestion. BamHI restriction pattern of the two high molecular weight bands from each of the 13 fusants matched the pattern of 1158a plasmids (Fig.…”

“…In electrophoretic analysis, both parental monokaryons of L. edodes used in this study were found to retain a set of all plasmids harbored by their original dikaryons, namely two plasmids [11.1kb (pLE2) and 12.1kb (pLE3C)] for 1158a and its derived dikaryon TMIC-1158, and two plasmids [9.0kb (pLE1) and 12.3kb (pLE3D)] for 1569a and its derived dikaryon TMIC-1569 as reported previously 3 ( Fig. 1).…”

“…Extraction of total DNA from lyophilized mycelia was done by the procedure of Fukumasa-Nakai et al 3 A portion of the total DNA was examined by electrophoresis on a 1% agarose (Type S, Nippon Gene, Tokyo, Japan) slab gel in TAE (40 mM Tris/acetate, 10 mM EDTA, pH 8.0) at 5 V/cm for 4 h for plasmid detection. Plasmids were detected 4 on a UV transilluminator after staining the gel with ethidium bromide (0.5 µg/ml).…”

“…However, although Fukumasa-Nakai et al 3 characterized six different linear mitochondrial plasmids and demonstrated that their transmission pattern in sexual crosses is uniparental, there is no evidence for behavior of the plasmids in protoplast cell fusion. In this study we investigated the transmission of mitochondrial plasmids in protoplast cell fusants between compatible monokaryons of L.…”