DNA条形码在热带龙脑香科树种鉴定中的应用

龙脑香科植物是东南亚地区重要的热带木材来源树种, 对其开展DNA条形码评估在林业监管及森林资源保护等方面具有非常重要的实际应用价值。通过对龙脑香科植物样品进行rbcL、matK、trnL-trnF和ITS2四个片段的扩增和测序, 结合GenBank下载的数据, 共获得龙脑香科树种14属244种共计899条序列。通过比较4个片段的通用性、序列特征、种内和种间的遗传变异, 基于Best Match (BM)、Best Close Match (BCM)、相似性搜索算法(BLAST)和邻接树(NJ) 4种方法评估DNA条形码对于龙脑香科树种的鉴定能力。结果表明, ITS2在龙脑香科树种中鉴定效率最高, 通过优化的扩增体系能够从该科植物叶片中获得较高质量的ITS2片段; 叶绿体matK片段扩增和测序效率为100%, 且种内及种间遗传变异明显, 鉴定成功率高于其它叶绿体片段, 并据此提出ITS2和matK适合作为龙脑香科树种的DNA条形码。

Use of DNA Barcoding in Identifying Tropical Trees from Dipterocarpaceae

Plants from Dipterocarpaceae are vital tropical timber trees in Southeast Asia. They have high potential in forest supervision, forest resource protection and other aspects to evaluate the efficiency of DNA barcodes. We obtained 899 sequences from 244 species for 14 genera combined with sequences from the GenBank. We amplified and sequenced four DNA regions (rbcL, matK, trnL-trnF and ITS2) in samples from the family Dipterocarpaceae. The discrimination ability of DNA barcodes was evaluated by using effective sequence ratios, characteristics of sequences, divergence of intra- and inter-varieties, and identification success rates (Best Match, Best Close Match, BLAST and neighbor-joining methods). The ITS2 fragment showed the highest identification efficiency. High-quality ITS2 sequence can be obtained from the leaves of Dipterocarpaceae plants by using an optimized amplification system. The matK fragment showed obvious genetic variation and 100% amplification and sequencing efficiency, and its identification ability was higher than with other chloroplast markers. Therefore, ITS2 and matK are suitable markers for tropical trees from Dipterocarpaceae.