Mayu Maeda, Jamjan Meeboon, Vasyl P Heluta, Shu-Yan Liu, Shu Rong Tang, Susumu Takamatsu
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引用次数: 0
Abstract
The genus Fraxinus (Oleaceae), known as ash trees, currently comprises 43 recognized species that are distributed in temperate and subtropical regions of the Northern Hemisphere. Two Phyllactinia species, P. fraxini and P. fraxinicola, have been known on Fraxinus spp. so far. In this study, powdery mildews belonging to Phyllactinia were collected on Fraxinus spp. from different areas of the world to make molecular and morphological analyses. These specimens are divided into four distinct molecular phylogenetic groups, which are distinguishable by their morphology and/or host preference. Two new species, viz. P. japonica occurring on F. sieboldina and F. lanuginosa f. serrata, and P. fraxini-longicuspidis on F. longicuspis, are proposed in this study. An epitype is designated for P. fraxini. This study indicates very high host specificity among the four Phyllactinia species on Fraxinus, suggesting that genetic isolation by host specificity played a more important role than geographic segregation in the speciation events of these Phyllactinia species. Evolutionary timing calculated by molecular clock analysis suggests that these powdery mildews diverged in accordance with host phylogeny after divergence of host plants.
白蜡树属(油桐科)目前有 43 个公认的物种,分布在北半球的温带和亚热带地区。迄今为止,在梣属植物上已知有两种白粉菌(Phyllactinia),即 P. fraxini 和 P. fraxinicola。本研究从世界不同地区的梣树上采集了属于 Phyllactinia 的白粉菌,并对其进行了分子和形态学分析。这些标本被划分为四个不同的分子系统发育群,它们可以通过形态和/或寄主偏好进行区分。本研究提出了两个新种,即发生在 F. sieboldina 和 F. lanuginosa f. serrata 上的 P. japonica,以及发生在 F. longicuspis 上的 P. fraxini-longicuspidis。P. fraxini 被指定为一种表型。这项研究表明,梣树上的四个Phyllactinia物种具有很高的寄主特异性,这表明在这些Phyllactinia物种的物种演化过程中,寄主特异性所导致的遗传隔离比地理隔离发挥了更重要的作用。通过分子钟分析计算的进化时间表明,这些白粉病菌是在寄主植物分化后根据寄主系统发育进行分化的。
期刊介绍:
Mycoscience is the official English-language journal of the Mycological Society of Japan and is issued bimonthly. Mycoscience publishes original research articles and reviews on various topics related to fungi including yeasts and other organisms that have traditionally been studied by mycologists. The research areas covered by Mycoscience extend from such purely scientific fields as systematics, evolution, phylogeny, morphology, ecology, physiology, biochemistry, genetics, and molecular biology, to agricultural, medical, and industrial applications. New and improved applications of well-established mycological techniques and methods are also covered.