Summerfield Tina C, Eaton-Rye Julian J
Department of Biochemistry, University of Otago, PO Box 56, Dunedin, New Zealand.
New Phytol. 2006;170(3):597-607. doi: 10.1111/j.1469-8137.2006.01701.x.
Pseudocyphellaria crocata, P. neglecta and P. perpetua specimens were examined to investigate links between genetic variation and morphology, geographical distribution and cyanobiont specificity. Fungal internal transcribed spacer (ITS), beta-tubulin and cyanobacterial tRNA(Leu) (UAA) intron sequences were used to investigate symbiont diversity in these lichens. Specimens were morphologically distinct but could not be distinguished by ITS sequences. Phylogenetic analyses split the P. crocata specimens into two clades, the larger of which contained P. neglecta and P. perpetua. Five cyanobionts were identified; two of these were in a number of specimens, while three were each restricted to a single lichen thallus. Fungus-specific molecular markers indicated that all specimens belonged to a single phylogenetic species. However, this may contain a cryptic species. Geography was linked to genetic diversity with Canadian specimens forming a monophyletic group, and most Southern Hemisphere specimens grouping together, although Chile represented a hot spot of genetic diversity. There was no connection between fungal genetic diversity and cyanobiont choice, consistent with the presence of a common pool of cyanobionts.
对橙黄拟杯点衣、疏叶拟杯点衣和永存拟杯点衣的标本进行了研究，以探讨遗传变异与形态、地理分布和蓝藻共生体特异性之间的联系。利用真菌内部转录间隔区（ITS）、β-微管蛋白和蓝藻tRNA（Leu）（UAA）内含子序列来研究这些地衣中的共生体多样性。标本在形态上有明显差异，但无法通过ITS序列进行区分。系统发育分析将橙黄拟杯点衣标本分为两个进化枝，其中较大的一个进化枝包含疏叶拟杯点衣和永存拟杯点衣。鉴定出了五种蓝藻共生体；其中两种存在于多个标本中，而另外三种分别局限于单个地衣叶状体。真菌特异性分子标记表明，所有标本都属于一个单一的系统发育物种。然而，这可能包含一个隐存种。地理因素与遗传多样性相关，加拿大的标本形成一个单系类群，大多数南半球标本聚集在一起，尽管智利是遗传多样性的一个热点地区。真菌遗传多样性与蓝藻共生体的选择之间没有关联，这与存在一个共同的蓝藻共生体库一致。
