Data from: Promise and challenge of DNA barcoding in Venus slipper (Paphiopedilum)

Orchidaceae are one of the largest families of flowering plants, with over 27,000 species described and all orchids are listed in CITES. Moreover, the seedlings of orchid species from the same genus are similar. The objective of DNA barcoding is rapid, accurate, and automated species identification, which may be used to identify illegally traded endangered species from vegetative specimens of Paphiopedilum (Venus slipper), a flagship group for plant conservation with high ornamental and commercial values. Here, we selected eight chloroplast barcodes and nrITS to evaluate their suitability in Venus slippers. The results indicate that all tested barcodes had no barcoding gap and the core plant barcodes showed low resolution for the identification of Venus slippers (18.86%). Of the single-locus barcodes, nrITS is the most efficient for the species identification of the genus (52.27%), whereas matK + atpF-atpH is the most efficient multi-locus combination (28.97%). Therefore, we recommend the combination of matK + atpF-atpH + ITS as a barcode for Venus slippers. Furthermore, there is an upper limit of resolution of the candidate barcodes, and only half of the taxa with multiple samples were identified successfully. The low efficiency of these candidate barcodes in Venus slippers may be caused by relatively recent speciation, the upper limit of the barcodes, and/or the sampling density. Although the discriminatory power is relatively low, DNA barcoding may be a promising tool to identify species involved in illegal trade, which has broad applications and is valuable for orchid conservation.

兰科（Orchidaceae）是被子植物最大的科之一，已描述物种逾27000种，且所有兰科植物均被列入《濒危野生动植物种国际贸易公约》（CITES）。此外，同属兰科植物的幼苗形态相似度极高。DNA条形码（DNA barcoding）的核心目标是实现快速、准确且自动化的物种鉴定，可用于从兜兰属（Paphiopedilum，俗称金星拖鞋兰）的营养体标本中甄别非法交易的濒危物种——兜兰属兼具极高观赏与商业价值，是植物保护领域的旗舰类群。本研究选取8个叶绿体条形码及核核糖体内转录间隔区（nrITS），评估其在兜兰属物种鉴定中的适用性。结果显示，所有受试条形码均未形成条形码间隙，且植物核心条形码对兜兰属的鉴定分辨率仅为18.86%，表现不佳。在单基因位点条形码中，nrITS对该属物种的鉴定效率最高，达52.27%；而多位点组合中，matK + atpF-atpH的鉴定效率最优，为28.97%。因此，本研究推荐将matK + atpF-atpH + ITS组合作为兜兰属的专用条形码标记。此外，候选条形码的鉴别能力存在上限，仅半数带有多份采样的类群可被成功鉴定。兜兰属候选条形码鉴定效率偏低的原因可能包括：物种形成事件相对较近、条形码本身的鉴别上限，以及/或采样密度不足。尽管鉴别能力相对有限，但DNA条形码仍有望成为识别非法交易濒危兰科物种的有效工具，其应用前景广阔，对兰科植物保护具有重要价值。