North Carolina State University, Department of Plant Pathology, Raleigh, North Carolina 27695-7616.
Mycologia. 2013 Nov-Dec;105(6):1524-34. doi: 10.3852/12-336. Epub 2013 Aug 8.
The wood-decay fungi Fomes fasciatus and F. fomentarius share many morphological characters that historically have made species delimitation challenging. We examined morphological, molecular and physiological characters of basidiomata and pure cultures of F. fasciatus and F. fomentarius sampled from multiple plant hosts and geographic regions in the United States to determine whether they support separation of the two species. We find that mean basidiospore size is significantly larger in F. fomentarius and represents the most informative morphological character for delineating the species. Basidiomata and pore-surface shape provided additional resolution of the species, but these characters often overlap and are more variable than basidiospore size. Phylogenetic analyses of ITS and RPB2 sequences suggest that F. fasciatus and F. fomentarius represent distinct evolutionary lineages. The two species share less than 88% maximum identity for the ITS region. Limited intraspecific sequence variation at each locus also was observed. In vitro experiments of hyphal-growth response to a wide range of temperatures support differences in physiology between the two species.
腐朽真菌 Fomes fasciatus 和 F. fomentarius 具有许多相似的形态特征，这使得物种界定一直具有挑战性。我们研究了来自美国多个植物宿主和地理区域的 F. fasciatus 和 F. fomentarius 的担子果和纯培养物的形态、分子和生理特征，以确定它们是否支持这两个物种的分离。我们发现，F. fomentarius 的担孢子大小明显较大，是区分这两个物种最具信息量的形态特征。担子果和孔面形状为物种的划分提供了额外的分辨率，但这些特征通常重叠，而且比担孢子大小更具变异性。ITS 和 RPB2 序列的系统发育分析表明，F. fasciatus 和 F. fomentarius 代表不同的进化谱系。这两个物种的 ITS 区域的最大同一性小于 88%。在每个基因座上也观察到有限的种内序列变异。菌丝生长对广泛温度范围的反应的体外实验支持这两个物种在生理学上的差异。
