ABSTRACT

Plantago princeps var. princeps is an endangered native Hawaiian plant, and part of the recovery plan includes repopulation using plants grown in a nursery. However, disease pressure from downy mildew is hindering repopulation efforts. The organism associated with the downy mildew was determined to be a Peronospora species with brown, ellipsoid conidia measuring 21 by 16 µm on average, which was morphologically different from validly described species of Peronospora that infect Plantago species, but it was morphologically similar to the invalidly published species Peronospora lanceolatae (Art. 40.1). Comparison of mitochondrial cytochrome oxidase subunit I (cox1), mitochondrial cytochrome oxidase subunit II (cox2), nuclear internal transcribed spacer (ITS), and nuclear 28S rRNA D1–D2 (28S) loci revealed the unknown Peronospora to be molecularly divergent from Peronospora alta and Peronsopora plantaginis, but very similar to Peronospora from Plantago lanceolata, the type host of P. lanceolatae. Phylogenetic trees inferred with maximum likelihood and Bayesian inference from a concatenated alignmaent and individual gene trees confirmed the divergence of the unknown Peronospora from P. alta and P. plantaginis and its similarity to P. lanceolatae. However, attempts to inoculate Plantago lanceolata with the strain from Plantago princeps var. princeps were unsuccessful, which, in conjunction with divergence in ITS, suggests that the unknown Peronospora is specific to Plantago princeps var. princeps. Herein, the Peronospora strain on Plantago princeps var. princeps is described as the new species Peronospora kuewa based on morphology, molecular phylogenetics, and host specificity. In addition, Peronospora gaponenkoae is described here to honor Nina Ivanova Gaponenko on the basis of her description of P. lanceolatae.

摘要

车前草变种。Princeps是一种濒临灭绝的夏威夷本土植物，恢复计划的一部分包括使用苗圃种植的植物重新繁殖。然而，霜霉病的疾病压力正在阻碍重新繁殖的努力。与霜霉病相关的微生物被确定为霜霉属物种，具有棕色椭圆形分生孢子，平均为 21 x 16 µm，在形态学上与有效描述的感染车前子物种的霜霉属物种不同，但在形态学上与无效的霜霉属物种相似。已发表的物种披针孢 Peronospora lanceolatae（第 40.1 条）。线粒体细胞色素氧化酶亚基I（cox1)、线粒体细胞色素氧化酶亚基 II ( cox 2)、核内转录间隔区 (ITS) 和核 28S rRNA D1-D2 (28S) 位点揭示未知霜霉属与高霜霉属和车前霜霉在分子上不同，但非常相似从Plantago lanceolata到Peronospora，P . lanceolatae的类型宿主。系统发育树的最大似然推断和贝叶斯推断从连接的排列和单个基因树证实了未知霜霉属与P. alta和P. plantaginis的分歧及其与披针叶树。然而，尝试用来自车前子变种的菌株接种车前草。Princeps是不成功的，这与 ITS 的分歧相结合，表明未知的霜霉属是车前子变种所特有的。王子。在本文中，车前子变种上的霜霉属菌株。princeps的被描述为新种霜霉kuewa基于形态学，分子系统和宿主特异性。此外，霜霉病菌在这里描述是为了纪念 Nina Ivanova Gaponenko，根据她对P. lanceolatae 的描述。