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Abstract: Ribosomal DNA polymorphism has been used to type strains as well as for phylogeny analyses. In Lentinula edodes, the ITS regions are sufficiently conserved (Hibbett et al. 1995) to be used to trace lineage relationships. Hibbett et al. (1995 & 1998) identified five lineages in Asia-Australasia with two lineages (named group I and V) appearing in China. As the sample size of all these earlier smdies was rather small, we carried out a large scale and more detailed collection program in China. This report will focus attention on three provinces that are not among those in which traditional cultivation is popular. These are central Hubei, north central Shaanxi and the most south west Yunnan. Several fruit bodies from a single fallen log and fruit bodies from different logs were collected and used for culture isolation (Chiu et al. 1999). Direct sequencing of the ITS regions as marked by fungal-specific primer set (ITS4 and ITS5) was performed. The results reveal that a dominant group I rDNA lineage appears in these three provinces. Isolates of the group V lineage previously reported in Nepal and Hubei were found in Shaanxi province instead. However, novel rDNA sequences (not belonging to any of the five lineages previously described) were found in the three provinces. Thus, several previously unsuspected rDNA lineages are present in China. Also, as isolates belonging to different rDNA lineages were found growing in one single log, it is evident that genetic recombination has freely occuned. This accounts for the high genetic polymorphism existing in the remote mountainous areas of China. Protecting the environment from unsympathetic exploitation is the best strategy for conserving this natural resource.
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