University of Hawaii at Manoa, College of Tropical Agriculture and Human Resources, Department of Plant and Environmental Protection Sciences, Cooperative Extension Service, 875 Komohana Street, Hilo, Hawaii 96720, USA.
Mycologia. 2010 Jan-Feb;102(1):122-34. doi: 10.3852/08-209.
A homothallic, papillate Phytophthora species causing foliar and fruit blight of noni (Morinda citrifolia var. citrifolia) in Hawaii was identified. The asexual phase of this species is characterized by the production of umbellate sporangiophores and papillate sporangia that are ellipsoid and obpyriform with conspicuously tapered bases and possess caducous, medium to long pedicels. The sexual phase is characterized by the production of oogonia with tapered bases, small amphigynous antheridia and thick-walled, plerotic oospores. The morphology of the taxon does not match any of the valid 95 Phytophthora species described to date. Phylogenetic analysis based on sequences of the internal transcribed spacer rDNA region (ITS) and the translation elongation factor 1 alpha (EF-1 alpha) of this taxon and those from other Phytophthora species from GenBank and the Phytophthora database indicates that the new taxon is most closely related to species in ITS clade 10, including P. kernoviae, P. boehmeriae and the recently described P. gallica. The most closely related species is P. kernoviae, an invasive plant pathogen causing bleeding stem lesions on forest trees (beech, Fagus sylvatica) and foliar necrosis of ornamentals (rhododendron, pieris and magnolia) in the UK, and isolated in New Zealand from necrotic cherimoya shoots and fruits and soil. Although the morphological characters of the sexual phase of P. morindae and P. kernoviae are similar, the umbellate sporangiophores produced by the new taxon marks the main morphological distinction. In this paper we describe the morphological characteristics, the phylogenetic relationships and pathogenicity characteristics that support the description of this taxon as a new species with the proposed name Phytophthora morindae sp. nov.
一种同宗配合、具乳突的疫霉种引起了夏威夷诺丽（Morinda citrifolia var. citrifolia）的叶部和果实疫病，该种的无性阶段的特征是产生伞形孢子梗和具乳突的孢子囊，呈椭圆形和倒卵形，基部明显变细，具易脱落的中长柄。有性阶段的特征是产生具渐细基部的卵孢子，小的雌雄同体的藏卵器和厚壁、充满原生质的卵孢子。该分类群的形态与迄今为止描述的 95 种有效疫霉种都不匹配。基于 ITS 区（ITS）和翻译延伸因子 1α（EF-1α）的序列对该分类群和来自 GenBank 和 Phytophthora 数据库的其他疫霉种的系统发育分析表明，新分类群与 ITS 分支 10 中的种最为密切相关，包括 P. kernoviae、P. boehmeriae 和最近描述的 P. gallica。最密切相关的种是 P. kernoviae，一种入侵植物病原体，可引起英国森林树木（山毛榉，Fagus sylvatica）的出血茎病和观赏植物（杜鹃、悬钩子和木兰）的叶坏死，并从新西兰的坏死鳄梨嫩枝和果实及土壤中分离出来。尽管 P. morindae 和 P. kernoviae 的有性阶段的形态特征相似，但新分类群产生的伞形孢子梗是主要的形态区别。本文描述了支持该分类群描述为具有新名称 Phytophthora morindae sp. nov. 的新种的形态特征、系统发育关系和致病性特征。
