基于ITS序列分析探讨我国栽培凤尾菇的分类地位

Taxonomic Status of Pleurotus sajor-caju Cultivated in China Based on ITS Sequence Analysis

针对我国栽培凤尾菇(Pleurotus sajor-caju)及其近缘种共10个菌株的ITS序列,应用特异引物进行PCR扩增,对其产物进行测序,并从GenBank上下载侧耳属(Pleurotus)3个种7条ITS序列、韧伞属(Lentinus)的4条ITS序列和香菇属(Lentinula)的3条ITS序列,以冬虫夏草(Cordyceps sinensis)和蛹虫草(Cordyceps militaris)为外类群,用NJ(Neighbor-joining)法构建系统发育树,结果表明:凤尾菇在侧耳属分支上与侧耳属内种的相似性达98.5%以上,韧伞属和香菇属的属内相似性也均为98%以上,而侧耳属和韧伞属、香菇属的属间相似性仅约80%,故凤尾菇应归于侧耳属;在进一步研究中,将该凤尾菇与其近缘种的ITS1-5.8S-ITS2序列作碱基完全比对,结果发现它与肺形侧耳(Pleurotus pulmonarius)的碱基完全一致,而与其它近缘种均存在较大碱基差异,因此,目前我国广泛栽培的凤尾菇与肺形侧耳可能是同物异名种,建议订正其名称,将其拉丁名统一为P.pulmonarius。本研究首次将ITS序列分析和碱基比对结合对凤尾菇的分类地位及拉丁名进行研究,结果表明ITS序列分析在近缘种的分类鉴定上很有价值。

In order to clarify the taxonomic status of Pleurotus sajor-caju, we determined ITS sequences from six Pleurotus （including one strain of P. sajor-caju） and four Lentinula strains cultivated in China. Data were combined with ITS sequences from 11 related strains, including Pleurotus, Lentinus, Lentinula, Cordyceps and Ophiocordyceps, obtained from GenBank to construct a phylogenetic tree using the Neighbor-joining method with Cordyceps militaris and Ophiocordyceps sinensis as the outgroups. The P. sajor-caju test strain was located on a branch that incorporated all the other Pleurotus strains examined with a shared similarity value ~〉98.5%. Similarity values among Lentinus and Lentinula strains was also 〉98%, but only 80% when all three genera were compared. In a further complete alignmentstudy, comparison of sections of ITS1-5.8S-ITS2 sequences from four P. sajor-caju strains with corresponding sequences from strains of P. pulmonarius, P. ostreatus and P. eryngii revealed that the sequences from P. sajor-caju and P. pulmonarius strains were identical but were different from the other Pleurotus strains. Our data indicate that the P. sajor-caju test strain was synonymous with P. pulmonarius and recommend that it be renamed accordingly.