Origin of a new Phytophthora pathogen through interspecific hybridization
Origin of a new Phytophthora pathogen through interspecific hybridization
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DOI：
10.1073/pnas.96.10.5878
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发表时间：
1999-05-11
影响因子：
11.1
通讯作者：
Duncan, JM
中科院分区：
文献类型：
--
作者：
Brasier, CM;Cooke, DEL;Duncan, JM
由外来真菌植物病原体的引入引起的植物病害流行是众所周知的现象。相关风险——由于引入的或引入的和常驻的真菌病原体之间的基因交换可能导致病原体进化加速——在很大程度上未被认识到。这部分是因为真菌中自然的种间杂交的例子非常罕见。潜在的进化发展范围从新宿主特异性的获得到全新病原体分类群的出现。我们从细胞学行为、rRNA编码DNA (rDNA)重复内转录间隔区中的附加核苷酸碱基以及总DNA的扩增片段长度多态性中提供证据，表明欧洲桤树的一种新的、侵略性的疫霉病原体包括 一系列异倍体种间杂种，涉及类似葡萄疫霉的物种和类似于草莓疫霉的未知分类群，这些杂种的明显发育不稳定、不寻常的形态变异性以及其内部转录间隔区重组的证据表明它们是最近起源的并且它们的进化仍在继续。此类进化事件发生的可能性很大。随着世界植物贸易的加强，这一数字将会增加。然而，目前使用的常规诊断程序不够灵敏，无法检测到它们。
Plant disease epidemics resulting from introductions of exotic fungal plant pathogens are a well known phenomenon. An associated risk-that accelerated pathogen evolution may be occurring as a consequence of genetic exchange between introduced, or introduced and resident, fungal pathogens-is largely unrecognized, This is, in part, because examples of natural, interspecific hybridization in fungi are very rare. Potential evolutionary developments range from the acquisition of new host specificities to emergence of entirely new pathogen taxa, We present evidence from cytological behavior, additive nucleotide bases in repetitive internal transcribed spacer regions of the rRNA-encoding DNA (rDNA), and amplified fragment length polymorphisms of total DNA that a new, aggressive Phytophthora pathogen of alder trees in Europe comprises a range of heteroploid-interspecific hybrids involving a Phytophthora cambivora-like species and an unknown taxon similar to Phytophthora fragariae, The hybrids' marked developmental instabilities, unusual morphological variability, and evidence for recombination in their internal transcribed spacer profiles indicates that they are of recent origin and that their evolution is continuing. The likelihood of such evolutionary events mag. be increasing as world trade in plants intensifies. However, routine diagnostic procedures currently in use are insufficiently sensitive to allow their detection.