Donahoo Ryan, Blomquist Cheryl L, Thomas Samantha L, Moulton John K, Cooke David E L, Lamour Kurt Haas
Department of Entomology and Plant Pathology, The University of Tennessee, 2431 Joe Johnson Drive, Rm 205, Ellington Plant Science, Knoxville, TN 37996, USA.
Mycol Res. 2006 Nov;110(Pt 11):1309-22. doi: 10.1016/j.mycres.2006.07.017. Epub 2006 Oct 25.
A previously unknown Phytophthora was recovered more than 60 times from evergreen hybrid azalea leaves collected during surveys for the sudden oak death pathogen Phytophthora ramorum in California and Tennessee. The novel Phytophthora was discovered when genomic DNA from this species cross-reacted with the ITS-based diagnostic PCR primers used to screen plants for the presence of P. ramorum. This species had caducous, semi-papillate sporangia, was homothallic with both paragynous and amphigynous antheridia, and was pathogenic on both wounded and intact azalea leaves. Nuclear and mitochondrial sequence data indicate that this species is related to, but distinct from, P. ramorum. AFLP analysis indicates that the isolates of this species have limited genotypic diversity and share no markers with P. ramorum. This paper presents the formal description of P. foliorum as a new species and underscores the need for caution when relying solely on DNA-based diagnostic tools.
在加利福尼亚州和田纳西州针对橡树猝死病原体恶疫霉（Phytophthora ramorum）进行调查期间，从常绿杂交杜鹃叶片上60多次分离出一种此前未知的疫霉。当该物种的基因组DNA与用于筛选植物中是否存在恶疫霉的基于内转录间隔区（ITS）的诊断性PCR引物发生交叉反应时，发现了这种新型疫霉。该物种具有脱落性、半乳头状孢子囊，是同宗配合的，具有侧生和周生雄器，并且对受伤和完整的杜鹃叶片均具有致病性。核序列和线粒体序列数据表明，该物种与恶疫霉相关，但又有所不同。扩增片段长度多态性（AFLP）分析表明，该物种的分离株基因型多样性有限，且与恶疫霉没有共享标记。本文对叶疫霉（P. foliorum）这一新物种进行了正式描述，并强调仅依靠基于DNA的诊断工具时需谨慎。
