Hassold Sonja, Lowry Porter P, Bauert Martin R, Razafintsalama Annick, Ramamonjisoa Lolona, Widmer Alex
Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland.
Missouri Botanical Garden, St. Louis, Missouri, United States of America.
PLoS One. 2016 Jun 30;11(6):e0157881. doi: 10.1371/journal.pone.0157881. eCollection 2016.
Illegal selective logging of tropical timber is of increasing concern worldwide. Madagascar is a biodiversity hotspot and home to some of the world's most sought after tropical timber species. Malagasy rosewoods belong to the genus Dalbergia (Fabaceae), which is highly diverse and has a pantropical distribution, but these timber species are among the most threatened as a consequence of intensive illegal selective logging and deforestation. Reliable identification of Dalbergia species from Madagascar is important for law enforcement but is almost impossible without fertile plant material, which is often unavailable during forest inventories or when attempting to identify logged trees of cut wood. DNA barcoding has been promoted as a promising tool for species identification in such cases. In this study we tested whether DNA barcoding with partial sequences of three plastid markers (matK, rbcL and trnL (UAA)) can distinguish between Dalbergia from Madagascar and from other areas of its distributional range, and whether Malagasy species can be distinguished from one another. Phylogenetic analyses revealed that the Malagasy Dalbergia species studied form two monophyletic groups, each containing two subgroups, only one of which corresponds to a single species. We characterized diagnostic polymorphisms in the three DNA barcoding markers that allow rapid discrimination between Dalbergia from Madagascar and from other areas of its distribution range. Species identification success based on individual barcoding markers or combinations was poor, whereas subgroup identification success was much higher (up to 98%), revealing both the value and limitations of a DNA barcoding approach for the identification of closely related Malagasy rosewoods.
非法选择性采伐热带木材在全球范围内日益受到关注。马达加斯加是生物多样性热点地区，拥有一些世界上最受追捧的热带木材物种。马达加斯加紫檀属于黄檀属（豆科），该属种类繁多，分布于泛热带地区，但由于密集的非法选择性采伐和森林砍伐，这些木材物种成为最受威胁的物种之一。从马达加斯加可靠鉴定黄檀属物种对执法至关重要，但如果没有可育的植物材料几乎不可能做到，而在森林清查期间或试图鉴定采伐树木或锯材时，可育植物材料往往难以获得。在这种情况下，DNA条形码技术已被推崇为一种有前景的物种鉴定工具。在本研究中，我们测试了利用三个质体标记（matK、rbcL和trnL（UAA））的部分序列进行DNA条形码分析，是否能够区分马达加斯加的黄檀属物种与其分布范围内其他地区的黄檀属物种，以及马达加斯加的物种之间是否能够相互区分。系统发育分析表明，所研究的马达加斯加黄檀属物种形成两个单系类群，每个类群包含两个亚群，其中只有一个亚群对应一个单一物种。我们鉴定了三个DNA条形码标记中的诊断性多态性，这些多态性能够快速区分马达加斯加的黄檀属物种与其分布范围内其他地区的黄檀属物种。基于单个条形码标记或其组合的物种鉴定成功率较低，而亚群鉴定成功率则高得多（高达98%），这揭示了DNA条形码技术在鉴定亲缘关系密切的马达加斯加紫檀时的价值和局限性。
