地黄属核基因与叶绿体基因DNA条形码比较研究

目的比较单拷贝核基因、叶绿体基因及ITS等DNA条形码在地黄属的物种分辨率,探讨地黄属种间亲缘关系。方法利用距离法与建树法分析了地黄属植物13个居群的12个单拷贝核基因、6个叶绿体基因以及ITS片段物种鉴定成功率,构建了地黄属系统发育树。结果叶绿体matk和rbc L、单拷贝核基因物种分辨率普遍较低,多基因联合分析有助于物种鉴定成功率的提高。在NJ树中,地黄-茄叶地黄聚为一支,其他物种都是单系群,裂叶地黄位于系统发育树基部。结论 ITS是地黄属物种鉴定的核心条形码,psb A-trnH、trnL-F、trnM-V、trnS-G可以作为备选方案,核基因RR255与R257可用作地黄专用鉴定条形码。四倍体地黄起源方式有待进一步澄清。

Comparison on DNA barcodes of nuclear and chloroplast gene fragments in Rehmannia Libosch. ex Fisch. et Mey. (Rehmanniaceae)

Objective To compare the usage of single-copy nuclear genes (SCNGs), chloroplast gene fragments and internal transcribed spacer (ITS) as DNA barcodes in plants of Rehmannia Libosch. ex Fisch. et Mey. and elucidate the interspecific relationships in the genus. Methods Distance and tree-based methods were performed to analyze 12 SCNGs, six cpDNA regions, and ITS fragment in 13 populations of Rehmannia Libosch. ex Fisch. et Mey. Neighbor-joining tree was constructed to investigate the relationships among the species. Results CpDNA regions (matK and rbcL) and SCNGs had lower identification rates than others, especially ITS. Multiple DNA barcodes combination would be helpful to improve the species identification rate. The NJ tree indicated that R. glutinosa and R. solanifolia were clustered together, other species in the genus were monophyletic, and R. piasezkii was the basal group. Conclusion ITS should be used as the core barcode in the genus while psbA-trnH, trnL-F, trnM-V, and trnS-G would be considered as the candidates, and nuclear genes R255 and R257 might be utilized as unique barcode for the identification of R. glutinosa. The origin of tetraploid species (R. glutinosa and R. solanifolia) still remains unknown and further works should be done to solve the question.