Laboratory of Plant Taxonomy and Evolution, Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan;
Am J Bot. 2007 Oct;94(10):1630-41. doi: 10.3732/ajb.94.10.1630.
Taxonomical classification of higher fungi remains an important challenge and can benefit from the application of molecular analysis. We propose that the ectomycorrhizal (EM) fungal taxa might include a number of cryptic species because there are few morphological characteristics useful for distinguishing among these fungi. Previously, host specificity in most EM fungi was thought to be low, but we suspect that confusion of cryptic species has led to an underestimate of fungal host specificity. We analyzed both nuclear and mitochondrial DNA sequences from Strobilomyces fungi and obtained evidence that what were previously described as four species can be grouped into 14 distinct lineages, suggesting that these lineages might be distinct biological species. Moreover, we identified host plants for Strobilomyces via nucleotide sequencing of both fungal and plant DNA from EM samples. Most lineages of Strobilomyces tested in this study were associated only with Fagaceae trees, even though Strobilomyces species were previously thought to be generalists with regard to hosts. Thus, we present an approach useful for identifying cryptic species and detecting the true host range of a set of EM fungi in natural conditions.
高等真菌的分类仍然是一个重要的挑战，可以受益于分子分析的应用。我们提出，外生菌根（EM）真菌类群可能包含一些隐种，因为很少有形态特征可用于区分这些真菌。以前，大多数 EM 真菌的宿主特异性被认为较低，但我们怀疑隐种的混淆导致对真菌宿主特异性的低估。我们分析了 Strobilomyces 真菌的核和线粒体 DNA 序列，并获得了证据，证明以前描述的四个种可以分为 14 个不同的谱系，这表明这些谱系可能是不同的生物种。此外，我们通过从 EM 样本中的真菌和植物 DNA 进行核苷酸测序，鉴定了 Strobilomyces 的宿主植物。在这项研究中测试的大多数 Strobilomyces 谱系仅与壳斗科树木有关，尽管以前认为 Strobilomyces 物种是宿主的多面手。因此，我们提出了一种在自然条件下识别隐种和检测一组 EM 真菌真实宿主范围的有用方法。
