Genetic homogeneity of cultivated strains of shiitake ( Lentinula edodes) used in China as revealed by the polymerase chain reaction

Abstract

Nineteen strains of shiitake (Lentinula edodes) which are used for spawn production for farms throughout mainland China were characterized by three arbitrarily-primed polymerase chain reaction (AP-PCR) profiles seven random amplified polymorphic DNA marker (RAPD) profiles and five restriction patterns (restriction fragment length polymorphism patterns of the PCR-amplified ribosomal DNAs; rDNA-RFLPs). For AP-PCR, 4–14 DNA bands were amplified for a particular strain while 1–9 DNA bands were amplified using RAPD. Among them only three of the strains tested showed different amplification profiles with most of the primers used. The others showed small differences in three or fewer DNA amplification profiles. All strains showed identical rDNA-RFLPs. The study indicates that cultivated strains of shiitake in China are genetically very homogeneous very like cultivated strains of Agaricus bisporus and Volvariella volvacea. However, our collection of L. edodes covers an enormous geographical area (approx. 1700 km N to S, 700 km E to W) and our results demonstrate that the shiitake industry in China depends on an extremely small gene pool. In comparison three wild strains collected from the same ecosystem in Fujian Province (SE China) showed more variable amplification profiles. This emphasises the importance of conservation of wild shiitake strains as a reserve of biodiversity for this important industry.