峨眉山区唇形科药用植物ITS2和mat K条形码序列鉴定

目的 评价以ITS2和matK序列作为DNA条形码对峨眉山区唇形科药用植物的鉴定效果。方法 从峨眉山区采集23种唇形科药用植物样本,提取DNA,PCR扩增ITS2序列,并从Genbank上分别下载54与51条唇形科植物的ITS2及matK序列;使用MEGA 5.0软件计算全部序列的种间、种内遗传距离及序列变异位点,构建Neighbor Joining(NJ)系统进化树,最后开展barcoding gap分析。结果 峨眉山唇形科药用植物的ITS2序列长度为190～237 bp,GC含量为53%～73%,具有较为明显的barcoding gap,对唇形科植物的识别率为94%,而matK序列的barcoding gap不显著,有明显重叠现象,对唇形科植物的识别率为96%。结论 ITS2从种水平上对唇形科植物有更好的鉴定能力,但matK序列对唇形科植物的识别率更高,因此,以ITS2为主,matK序列为辅的鉴定方法能够对唇形科药用植物进行快速、准确的鉴定和识别,准确阐明物种之间的亲缘关系,对峨眉山区唇形科药用植物资源的有效保护和合理开发提供了理论依据。

Identification and analysis on medicinal plants of Labiatae from Emei Mountain Area Using ITS2 and matK sequences

Objective To evaluate the efficiency of ITS2 and matK DNA barcode for the identification the Labiatae medicinal plants in Emei Mountain. Methods A total of 23 samples of Labiatae medicinal plants were harvested in Emei Mountain. The DNA was extracted and used for PCR to obtain the ITS2 sequences. Meanwhile, 54 ITS2 and 51 matK sequences of the medicinal plants in Labiatae were downloaded from Genbank. The interspecies and intraspecific genetic distance and sequence variation sites of all sequences were determined by MEGA 5.0 software. The Neighbor Joining (NJ) phylogenetic tree was constructed, and barcoding gap analysis was then performed. Results The length of various ITS2 sequence was distributed from 190 to 237 bp, with GC content of 53%-73%. Moreover, significant barcoding gap was observed when comparing the distances, the recognition rate for plants of the Labiatae family was 94%.The barcoding gap of the matK sequence was not significant, there was obvious overlap, and the recognition rate for the Labiatae family was 96%. Conclusion ITS2 has a better ability to identify Lamiaceae plants at the species level, but the matK sequence has a higher recognition rate for Lamiaceae plants. Therefore, the employment of ITS2 as core with matK as supplement was able to identify Lamiaceae plants quickly and accurately, and understand the genetic relationship between species accurately. This provides an important theoretical basis for the effective protection and rational development of the medicinal plant resources of the Labiatae plants in Emei Mountain.