CBS Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands;
Persoonia. 2009 Jun;22:83-94. doi: 10.3767/003158509X439364. Epub 2009 Apr 2.
Eucalyptus spp. are susceptible to a large number of foliar pathogens, some of which can cause serious defoliation and die-back. In this study, a single leaf spot on a Eucalyptus leaf collected in Madagascar revealed an unusual association of microfungi with disease symptoms. Initial observations indicated that the leaf spot was associated with Mycosphaerella marksii, a common pathogen of eucalypts. However, more intensive scrutiny showed the presence of several other microfungi co-occurring in this, and other leaf spots on the leaf. A total of 41 single conidial propagules were subsequently obtained from a single lesion for morphological study and DNA sequence comparisons. Based on these data, 11 members of the Capnodiales, including one species of Pestalotiopsis (Xylariales), were observed. Of the capnodialean taxa, nine could be cultivated, which revealed one known species, M. marksii, two taxa in the Cladosporium cladosporioides species complex that were not treated here, and six new species, including Passalora intermedia, Pseudocercospora madagascariensis, Teratosphaeria hortaea, Toxicocladosporium chlamydosporum, T. rubrigenum and T. veloxum. Results of this study highlight a remarkable fungal biodiversity that can occur within a very specific niche. Furthermore, the results emphasise the importance of verifying the identity of fungal isolates in culture, as many taxa, especially those of the Capnodiales, frequently co-occur in the same niche, lesion or leaf spot.
桉树易感染大量叶部病原菌，其中一些可导致严重落叶和枯梢。在本研究中，从马达加斯加采集的一片桉树叶上的单个叶斑显示出一种不寻常的微生物与病症的关联。初步观察表明，该叶斑与常见的桉树病原菌球腔菌属（Mycosphaerella）的马克西姆氏菌（M. marksii）有关。然而，更深入的观察表明，在该叶斑和叶片上的其他叶斑中还存在其他几种微生物共存。从单个病灶中总共获得了 41 个单个分生孢子用于形态学研究和 DNA 序列比较。基于这些数据，观察到了包括一个拟盘多毛孢属（Xylariales）种在内的 41 个胶孢炭疽菌目（Capnodiales）成员。在这些胶孢炭疽菌目中，有九个可以被培养，其中包括一个已知种，马克西姆氏菌（M. marksii），两个未在此处理的炭疽菌属（Cladosporium）无性型种复合体种，以及六个新种，包括中间拟盘多毛孢（Passalora intermedia）、马达加斯加拟尾孢（Pseudocercospora madagascariensis）、短梗隔孢腔菌（Teratosphaeria hortaea）、生藏壳孢（Toxicocladosporium chlamydosporum）、红隔孢腔菌（T. rubrigenum）和速旋隔孢腔菌（T. veloxum）。本研究结果突出了一个非常具体生态位内存在的显著真菌生物多样性。此外，结果强调了在培养中验证真菌分离物身份的重要性，因为许多分类群，尤其是胶孢炭疽菌目，经常在同一生态位、病灶或叶斑中共存。
