桑黄真菌分子鉴定及遗传多样性分析

药用真菌桑黄具有明显的抗肿瘤、抗氧化、增强免疫等药理活性,但研究者对其基源还没有达成共识,多种Phellinus属真菌被当作桑黄入药使用。采用rDNA ITS序列分析技术,对桑黄真菌进行分子鉴定及遗传多样性分析。通过rDNA ITS序列分析,成功鉴定出一份混淆样品(Phellinus spp-04),并将中国主要使用的桑黄真菌明确鉴定为P.baumii和P.linteus两种,未检测到P.igniarius的使用。依据rDNA ITS序列计算遗传距离并构建系统发育树,结果表明3种主要桑黄真菌存在明显的遗传分化,在系统发育树中明确聚为3个独立菌种类群。在3种桑黄真菌rDNA ITS序列中,存在颠换、转换及插入/缺失3种类型的变异位点,分别在P.linteus、P.baumii和P.igniarius中鉴定出9、9、8种rDNA ITS单倍型序列,不同单倍型菌种间遗传分歧度变化表现出明显的物种差异性。

Molecular identification and genetic diversity of a traditional Chinese medicinal fungus 'Sanghuang'

‘Sanghuang’, a traditional Chinese medicinal fungus, was famous for its pharmacological activities, such as anti-tumor, anti-oxidant and enhancing immune. However, until now its actual scientific name has not been confirmed, and some species, belonging to Phellinus were widely used for medicinal purposes as ‘Sanghuang’ in practice. In this study, the ribosomal DNA internal transcribed spacer (rDNA ITS) region was amplified and sequenced to identify the species of so-called ‘Sanghuang’ and detect its genetic diversity. One counterfeit ‘Sanghuang’ strain, Phellinus spp-04, was detected successfully, and the certified ‘Sanghuang’germplasms were distinguished as P. baumii or P. linteus unambiguously. Based on rDNA ITS sequences, the genetic distance and phylogenetic tree were obtained. The results showed that there were distinct genetic divergences among P. linteus, P. baumii and P. igniarius, which formed three separate species cluster in the topology tree obviously with high bootstrap value. Three types of variation sites, including transversion, transition and insertion/deletion, were detected from different rDNA ITS sequences, and 9, 9 and 8 haplotypes were identified in P. linteus, P. baumii and P. igniarius, respectively. The variation of genetic divergence of different haplotype strains indicated the obvious species difference. Generally speaking, the character of rDNA ITS sequence could be used as an exact, reliable and straightforward typing method to identify the fungus so-called ‘Sanghuang’ and explore its genetic diversity.