蒟蒻薯属 (薯蓣科) 植物DNA条形码研究

蒟蒻薯属（Tacca）植物种间在形态上差别不大，导致分类上存在一定的困难。DNA条形码是一种利用短的DNA标准片段来鉴别和发现物种的方法。本研究利用核基因ITS片段和叶绿体基因trnH psbA, rbcL, matK片段对蒟蒻薯属6个种的DNA条形码进行研究,对4个DNA片段可用性，种内种间变异，barcode gap进行了分析，采用Tree based和BBA两种方法比较不同序列的鉴定能力。结果显示：单片段ITS正确鉴定率最高，片段组合rbcL+matK正确鉴定率最高。支持CBOL植物工作组推荐的条码组合rbcL+matK可作为蒟蒻薯属物种鉴定的标准条码，建议ITS片段作为候选条码。丝须蒟蒻薯Tacca integrifolia采自西藏的居群与马来西亚居群形成了2个不同的遗传分支，且两者在形态上也存在一定的差异，很可能是一个新种。

Using DNA Barcoding in Genus Tacca (Dioscoreaceae)

Tacca (Dioscoreaceae) is a small genus which is taxonomically difficult because of a lack of obvious morphologically differences among species. DNA barcoding is a new method of rapid species identification and discovery using short, standardized genes or DNA regions. In this study, four candidate DNA barcoding regions that three (rbcL, matK, trnH psbA) from chloroplast genome and one (ITS) from the nuclear genome, were evaluated among 36 accessions representing 6 species of Tacca. The capability of those regions were evaluated by intra and inter specific divergence and barcode gap analyses, and the identification efficiency was assessed using Tree based and BBA methods. The results indicated that both ITS and the core barcode rbcL+matK proposed by CBOL exhibited the highest resolution as a single and combined data respectively. Based on overall performance: matK+rbcL can be considered as a potential barcode for identifying the species of Tacca, ITS can be used as a supplementary barcode. DNA barcoding revealed two distinct lineages of T.integrifolia distributed allopatrically in Tibet and Malaysia. And these two lineages with morphological variations may potentially represent new species.