United States Department of Agriculture - Agricultural Research Service, Fort Keogh Livestock & Range Research Laboratory, 243 Fort Keogh Road, Miles City, MT 59301-4016, USA.
New Phytol. 2010 Apr;186(2):484-95. doi: 10.1111/j.1469-8137.2009.03159.x. Epub 2010 Jan 19.
*Globally, exotic invaders threaten biodiversity and ecosystem function. Studies often report that invading plants are less affected by enemies in their invaded vs home ranges, but few studies have investigated the underlying mechanisms. *Here, we investigated the variation in prevalence, species composition and virulence of soil-borne Pythium pathogens associated with the tree Prunus serotina in its native US and non-native European ranges by culturing, DNA sequencing and controlled pathogenicity trials. *Two controlled pathogenicity experiments showed that Pythium pathogens from the native range caused 38-462% more root rot and 80-583% more seedling mortality, and 19-45% less biomass production than Pythium from the non-native range. DNA sequencing indicated that the most virulent Pythium taxa were sampled only from the native range. The greater virulence of Pythium sampled from the native range therefore corresponded to shifts in species composition across ranges rather than variation within a common Pythium species. *Prunus serotina still encounters Pythium in its non-native range but encounters less virulent taxa. Elucidating patterns of enemy virulence in native and nonnative ranges adds to our understanding of how invasive plants escape disease. Moreover, this strategy may identify resident enemies in the non-native range that could be used to manage invasive plants.
*在全球范围内，外来入侵物种威胁着生物多样性和生态系统功能。研究通常报告称，入侵植物在其入侵和原生范围中受到的天敌影响较小，但很少有研究调查其潜在机制。*在这里，我们通过培养、DNA 测序和控制致病性试验，调查了与原产于美国的树 Prunus serotina 及其非原产欧洲范围相关的土壤传播菌根病原体的流行率、物种组成和毒力的变化。*两项控制致病性试验表明，来自原生范围的菌根病原体引起的根腐病和幼苗死亡率分别增加了 38-462%和 80-583%，生物量减少了 19-45%，而来自非原生范围的菌根病原体则没有。DNA 测序表明，最毒的菌根生物类群仅从原生范围中取样。因此，原生范围中取样的菌根的更高毒性与范围之间的物种组成变化相对应，而不是同一菌根物种内的变化。Prunus serotina 在其非原生范围仍会遇到菌根，但遇到的毒力较低的生物类群。阐明原生和非原生范围中天敌毒力的模式，有助于我们了解入侵植物如何逃避疾病。此外，这种策略可能会识别非原生范围中的本地天敌，这些天敌可用于管理入侵植物。
