Institute for Agricultural and Fisheries Research, Plant Sciences Unit - Crop Protection, Burg. Van Gansberghelaan 96 box 2, 9820 Merelbeke, Belgium.
Fungal Biol. 2012 Nov;116(11):1178-91. doi: 10.1016/j.funbio.2012.09.003. Epub 2012 Oct 3.
Phytophthora ramorum is a recently introduced, aggressive Phytophthora species that has caused extensive mortality of oak and tanoak trees in the western USA and Japanese larch trees in the UK. P. ramorum is also present on Rhododendron, Camellia, and Viburnum in the nursery industry, which is thought to have been the pathway for its spread into new geographic regions including forests and natural ecosystems. Three lineages of P. ramorum have been described, informally designated EU1, NA1, and NA2, and each lineage is believed to originate from an as yet unknown exotic centre of origin. Preliminary SSR and sequence analysis of isolates from a UK P. ramorum survey revealed seven isolates with profiles that did not match the previously known lineages. Detailed SSR and multilocus sequence analysis of these isolates are presented, allowing us to assign these isolates to a new P. ramorum lineage, designated EU2. Although the known geographical origin of these isolates is currently limited to Northern Ireland and western Scotland, the EU2 lineage isolates have been obtained from four different host plants, including Japanese larch. All isolates are of A1 compatibility type, which implies that this finding does not increase the risk of outcrossing with the EU1 lineage isolates already present in the UK. The oldest EU2 strain was isolated in 2007 but no SSR-based intraEU2 lineage genotypic diversity was detected. The combination of these elements points to a recent introduction, despite emergency phytosanitary measures to control introduction and spread. A PCR-RFLP method for the rapid identification of EU2 lineage isolates is presented.
松材线虫是一种新近传入的、具有侵略性的松材线虫，它已导致美国西部的橡树和栓皮栎以及英国的日本落叶松大量死亡。松材线虫也存在于苗圃业的杜鹃、茶花和荚蒾属植物中，据认为这是其传播到新地理区域（包括森林和自然生态系统）的途径。已经描述了松材线虫的三个谱系，非正式地命名为 EU1、NA1 和 NA2，每个谱系都被认为起源于一个尚未确定的外来起源中心。对英国松材线虫调查中分离株的初步 SSR 和序列分析显示，有 7 个分离株的图谱与先前已知的谱系不匹配。对这些分离株进行了详细的 SSR 和多位点序列分析，使我们能够将这些分离株分配到一个新的松材线虫谱系 EU2 中。尽管这些分离株的已知地理起源目前仅限于北爱尔兰和苏格兰西部，但 EU2 谱系分离株已从包括日本落叶松在内的四种不同的宿主植物中获得。所有分离株均为 A1 相容性型，这意味着这一发现不会增加与已经存在于英国的 EU1 谱系分离株杂交的风险。最古老的 EU2 菌株于 2007 年分离，但未检测到 EU2 谱系内的 SSR 基于基因型多样性。这些因素的结合表明，尽管采取了紧急植物检疫措施来控制传入和传播，但仍有最近的传入。提出了一种用于快速鉴定 EU2 谱系分离株的 PCR-RFLP 方法。
