Host matrix has major impact on the morphology of Pseudoperonospora cubensis
Host matrix has major impact on the morphology of Pseudoperonospora cubensis
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寄主基质对古巴假霜霉的形态有重要影响
DOI：
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发表时间：
2011
影响因子：
1.8
通讯作者：
M. Thines
中科院分区：
文献类型：
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作者：
F. Runge;M. Thines
卵菌含有一些对开花植物具有重要经济意义的病原体。大多数昆虫的寄主范围相当窄，通常局限于单一寄主物种。在霜霉病和其他专性的生物营养植物寄生虫中，如白粉病和锈病，根据形态特征来划分物种往往是不可能的，因此往往只基于细微的差异。这导致了对这些生物体的广泛的物种概念的应用。因此，尽管报道了不同寄主种类对南瓜黑星病的形态差异，但相应的新病原菌并不被认为是独立的，据报道，南瓜黑星病的寄主范围包括温带至热带气候下的葫芦科50多种寄主。然而，最近的研究报告了其他霜霉菌属的寄主范围狭窄，并倡导狭义的物种概念。在这里，我们报告了一株黄瓜假丛孢菌在葫芦科五个不同部落的成功定殖，并证明了寄主基质对病原体的形态有重要影响。根据5个形态指标，所有寄主均存在显着差异。这些差异在系统发育无关的宿主中比在相关宿主中更明显。我们的研究结果为黄瓜黄孢霉具有广泛的寄主范围提供了证据，并表明基于形态特征的物种划分是不可行的。同样，在其他生物营养植物病原体中，情况也可能类似，因此需要进行彻底的形态、分子系统发育和交叉接种实验来识别物种。
Oomycetes contain some of the economically most important pathogens of flowering plants. Most have a rather narrow host range, often being restricted to single host species. In downy mildews and other obligate biotrophic plant parasites, like powdery mildews and rusts, delimitating species on grounds of morphological characteristics is often hardly possible and thus often based on only subtle differences. This has led to the widespread application of a broad species concept for these organisms. Consequently, despite the fact that morphological differences were reported for Pseudoperonospora cubensis from different host species, the corresponding new pathogen species were not accepted as being independent, and the host range of Pseudoperonospora cubensis is reported to encompass more than 50 host species in the Cucurbitaceae in temperate to tropical climates. However, recent studies have reported narrow host ranges for other downy mildew genera and advocated a narrow species concept. Here, we report successful colonisation of five different tribes of the Cucurbitaceae by a strain of Pseudoperonospora cubensis and demonstrate that the host matrix has a major impact on the morphology of the pathogen. On the basis of five morphological criteria significant differences could be found for all hosts. These differences were more pronounced in phylogenetically unrelated than in related hosts. Our results provide evidence for a broad host range of Pseudoperonospora cubensis and demonstrate that species delimitation based on morphological characters is not feasible in Pseudoperonospora on Cucurbitaceae. Also in other biotrophic plant pathogens, the situation could be similar, thus necessitating thorough morphological, molecular phylogenetic and cross inoculation experiments for species recognition.