Nexus-formatted text file of ISSR band presence/absence for 75 loci in Corallorhiza bentleyi

Mycoheterotrophic plants derive most or all carbon and nutrients from fungal partners and represent poorly understood components of forest biodiversity. Many are rare or endangered yet can be ecological indicators of forest ecosystem function due to their often highly specific fungal host requirements. One such species is the IUCN red-listed (‘vulnerable’), fully mycoheterotrophic orchid, Corallorhiza bentleyi. This recently described species is among the rarest plants in Appalachia, known from five counties in Virginia and West Virginia, USA. The species has a restricted range, small population size, and is self-pollinating. Here, an integrative approach was taken in conservation genetic assessment of C. bentleyi using floral morphometrics, simple-sequence repeats, and fungal host DNA to characterize variation within and among sampling localities. Morphology reveals some differentiation among individuals from six sampling localities. Surprisingly, most genetic variation is found within localities, contrary to the expectation for a selfing species. Fungal host DNA reveals extreme specificity upon a few genotypes of a single ectomycorrhizal host species, Tomentella fuscocinerea, across all localities. The conservation implications of morphological, genetic, and symbiotic diversity in this vulnerable species are discussed, and additional assessment of conservation status is recommended based on: an obligate reproductive mode of selfing, preventing benefits of outcrossing among genetically non-identical individuals; extreme host specificity, severely restricting niche space; and highly fragmented habitat under threat from anthropogenic disturbance. This study underscores the importance of integrative conservation assessment, analyzing multiple data sources, and reveals patterns not readily apparent from census-based assessments alone.菌异养植物（mycoheterotrophic plants）从真菌共生体中获取大部分乃至全部碳源与营养物质，是森林生物多样性中认知程度较低的类群。该类群多数物种较为稀少甚至处于濒危状态，且由于其通常对真菌宿主具有高度专一性，可作为森林生态系统功能的生态指示物。本特利珊瑚兰（Corallorhiza bentleyi）便是其中之一，它是被世界自然保护联盟（International Union for Conservation of Nature, IUCN）红色名录列为"易危"的完全菌异养兰花。该物种为近年新描述类群，是阿巴拉契亚地区最为珍稀的植物之一，目前仅在美国弗吉尼亚州与西弗吉尼亚州的5个县有分布记录。该物种分布范围狭窄、种群规模较小，且为自花授粉物种。本研究采用整合性方法，通过花形态测量学、简单序列重复（simple-sequence repeats）标记与真菌宿主DNA分析，对本特利珊瑚兰开展保护遗传学评估，以解析采样样地内及样地间的变异特征。形态学分析显示，来自6个采样样地的个体间存在一定程度的分化。令人意外的是，与自花授粉物种的预期遗传模式相反，该物种的大部分遗传变异存在于样地内部。真菌宿主DNA分析结果显示，所有采样样地的本特利珊瑚兰均对单一外生菌根宿主物种Tomentella fuscocinerea的少数基因型具有极端专一性。本研究讨论了该易危物种的形态、遗传与共生多样性所蕴含的保护学意义，并建议基于以下三方面开展进一步的保护现状评估：专性自花授粉的繁殖模式无法使遗传异质个体间通过异交获得演化收益；极端的宿主专一性严重限制了其生态位空间；以及栖息地高度破碎化，正面临人为活动干扰的威胁。本研究凸显了整合多源数据开展保护学评估的重要性，并揭示了仅基于种群普查评估难以发现的种群模式。