Department of Genetics, Forestry and Agricultural, Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa.
Mycologia. 2004 Sep-Oct;96(5):990-1001.
The fungal genera Endothia and Cryphonectria include some of the most important pathogens of forest trees. Despite available new technology, no comprehensive comparative study based on DNA sequence data and morphology has been done on the available isolates representing these two genera. The main objectives of this study were to assess the phylogenetic relationships among species of Cryphonectria and Endothia, for which cultures are available, and to establish a taxonomic framework based on DNA sequence and morphological data, which will aid future studies and identification of species in these and related genera. Comparisons were based on sequence variation found in the ITS region of the ribosomal RNA operon and two regions of the β-tu-bulin gene. In addition, the morphology of these species was examined. The phylogenetic data indicated that Endothia and Cryphonectria reside in two distinct phylogenetic clades. Cryphonectria parasitica, C. macrospora, C. nitschkei, C. eucalypti and C. radicalis represented the Cryphonectria clade. Endothia gyrosa and E. singularis were included in the Endothia clade. An isolate representing E. viridistroma grouped outside the Endothia clade and separately from other groups. Other clades outside the one encompassing Cryphonectria were those represented by the C. cubensis isolates and fungi isolated from Elaeocarpus dentatus originating from New Zealand. These clades could be distinguished from Endothia and Cryphonectria, based on anamorph morphology, stromatal structure and ascospore septation. Cryphonectria and Endothia, therefore, appear to be paraphyletic and taxonomic relationships for these fungi need to be revised.
真菌属 Endothia 和 Cryphonectria 包括一些最重要的森林树木病原体。尽管有新的技术可用，但尚未对代表这两个属的现有分离物进行基于 DNA 序列数据和形态学的全面比较研究。本研究的主要目的是评估 Cryphonectria 和 Endothia 物种之间的系统发育关系，这些物种有可用的培养物，并基于 DNA 序列和形态学数据建立一个分类框架，这将有助于未来对这些和相关属中物种的研究和鉴定。比较是基于核糖体 RNA 操纵子的 ITS 区域和 β-tu-bulin 基因的两个区域中发现的序列变异进行的。此外，还检查了这些物种的形态。系统发育数据表明，Endothia 和 Cryphonectria 位于两个不同的系统发育分支中。Cryphonectria parasitica、C. macrospora、C. nitschkei、C. eucalypti 和 C. radicalis 代表 Cryphonectria 分支。Endothia gyrosa 和 E. singularis 被包括在 Endothia 分支中。代表 E. viridistroma 的一个分离物在 Endothia 分支之外与其他群体分开。Endothia 之外的其他分支是由 C. cubensis 分离物和从新西兰原产的 Elaeocarpus dentatus 中分离的真菌代表的。这些分支可以根据无性形态、菌组织结构和分生孢子分隔来区分 Endothia 和 Cryphonectria。因此，Cryphonectria 和 Endothia 似乎是并系的，这些真菌的分类关系需要修订。
