背景:乌头属物种,属于毛貂科,具有很高的药用重要性,但由于其过度开发而被列入IUCN(国际自然保护联盟)红色名单。乌头属物种的精确鉴定同样重要,因为它们用于草药配方。本研究旨在开发一种有效的DNA条形码系统,用于乌头属物种的真实鉴定。
结果:5种乌头属物种的一组92个条形码基因序列(包括本研究中开发的12个和从NCBI中检索的80个)(A。异叶,A.vialoceum,A.japonicum,A.napellus,和Stapfianum)使用三种方法(基于树的,基于距离,和基于相似性)的物种歧视。发现PWG距离方法对物种区分最有效。PWG-距离的判别率从33.3%(rbcL+trnH-psbA)到100%(ITS,rbcL+ITS,ITS+trnH-psbA和rbcL+ITS+trnH-psbA)。在DNA条形码及其组合中,ITS标记的物种歧视程度最高(NJ-40%,PWG-100%和BLAST-40%),其次是trnH-psbA(NJ-20%,PWG-60%和BLAST-20%)。与其他单个条形码及其组合相比,ITS还具有更高的条形码间隙。Further,我们还分析了六种乌头植物(A.balfourii,A.ferox,A.异叶树,A.rotundifolium,喜马拉雅西部的A.soongaricum和A.violaceum)。通过基于树的方法使用具有100%物种分辨率的ITS条形码基因清楚地区分这些物种。
结论:ITS显示出最佳的物种辨别能力,并用于开发乌头属物种的物种特异性条形码。在本研究中开发的DNA条形码可用于鉴定乌头属物种。
BACKGROUND: Aconitum species, belonging to Ranunculaceae, have high medicinal importance but due to their overexploitation come under IUCN (International Union for Conservation of Nature) red list. The precise identification of the Aconitum species is equally important because they are used in herbal formulations. The present study aimed to develop an efficient DNA barcode system for the authentic identification of Aconitum species.
RESULTS: A set of 92 barcode gene sequences (including 12 developed during the present study and 80 retrieved from NCBI) of 5 Aconitum species (A. heterophyllum, A. vialoceum, A. japonicum, A. napellus, and A. stapfianum) were analyzed using three methods (tree-based, distance-based, and similarity-based) for species discrimination. The PWG-distance method was found most effective for species discrimination. The discrimination rate of PWG- distance ranged from 33.3% (rbcL + trnH-psbA) to 100% (ITS, rbcL + ITS, ITS + trnH-psbA and rbcL + ITS + trnH-psbA). Among DNA barcodes and their combinations, the ITS marker had the highest degree of species discrimination (NJ-40%, PWG-100% and BLAST-40%), followed by trnH-psbA (NJ-20%, PWG-60% and BLAST-20%). ITS also had higher barcoding gap as compared to other individual barcodes and their combinations. Further, we also analyzed six Aconitum species (A. balfourii, A. ferox, A. heterophyllum, A. rotundifolium, A. soongaricum and A. violaceum) existing in Western Himalaya. These species were distinguished clearly through tree-based method using the ITS barcode gene with 100% species resolution.
CONCLUSIONS: ITS showed the best species discrimination power and was used to develop species-specific barcodes for Aconitum species. DNA barcodes developed during the present study can be used to identify Aconitum species.