豆蔻属药用植物DNA条形码鉴定研究

目的：针对鉴定十分困难的豆蔻属药用植物筛选适合其鉴定的DNA条形码序列,探索豆蔻属药用植物鉴定新方法。方法：对该属植物36个物种,46个样本的8个候选条形码序列（psbA- trnH, matK, rbcL, psbK-psbI, rpoB, atpB-rbcL, ITS, ITS2）进行PCR扩增、测序和序列分析,我们采用了4种方法对于数据进行分析,应用Mega4.1计算不同序列的种间和种内遗传距离（K-2P）;用Wilcoxon秩和检验比较不同序列的变异性;用Taxon DNA软件评估“Barcoding Gap”;用Blast、Distance方法检验物种鉴定的可靠性。结果：ITS2和ITS序列变异显著,物种水平鉴定成功率达100％,其它6个候选序列（psbA-trnH, matK, rbcL, psbK-psbI, rpoB, atpB-rbcL）不能有效鉴定豆蔻属物种。结论：本文推荐将ITS2和ITS作为豆蔻属药用植物潜在的DNA条形码序列,并依此建立该属药用植物的DNA条形码鉴定方法。

Identification of Amomum (Zingiberaceae) through DNA Barcodes

It is very difficult to identify Amomum medicinal plants. In this study, we tested 8 candidate DNA barcodes (psbA-trnH, matK, rbcL, psbK-psbI, rpoB, atpB-rbcL, ITS, ITS2) to choose suitable barcodes for Amomum medicinal plants. 46 specimens representing 36 species were amplified, sequenced and analyzed. Four methods were used to analyze the data. Mega4.1 software was used to calculate intraspecific variation and interspecific divergence. Wilcoxon signed rank test was used to compare divergence among different barcodes. Taxon DNA software was adopted to evaluate the "barcoding gap". The distance and blast method was employed to test the reliability of different barcodes at the species level. The results showed that 6 out of the 8 candidate barcodes (psbA-trnH, matK, rbcL, psbK-psbI, rpoB, atpB-rbcL) displayed no significant divergence at the species level, while the other 2 candidate barcodes had significant divergence and high species identification reliability(100%). ITS2 and ITS may be the potential DNA barcodes for the identification of Amomum medicinal plants, thus making the establishment of new identification methods for this genus possible.