目的 分析14種山藥種質ITS序列，為山藥種質資源分子鑒別和進化關系研究提供依據。方法 PCR克隆擴增ITS序列并進行雙向測序，Clustal X（v1.83）軟件進行序列比對，Mega（v4.1）計算序列核苷酸比例及遺傳距離，并構建鄰接樹（Neighbor-joining tree，NJ Tree）和最大簡約樹（Maximum parsimony tree，MP Tree）。結果 14種山藥種質ITS序列全長為558～594 bp，其中ITS1長度為141～165 bp，ITS2長度為146～158 bp；ITS序列存在大量的轉換、顛換，轉化/顛換比率為5.347，ITS1和ITS2序列均顯示102個變異位點；14種山藥種質K2-P遺傳距離為0～0.517 2；薯蕷Dioscorea opposita、褐苞薯蕷Dioscorea persimilis、日本薯蕷Dioscore japonica關系親密，組成單一支系；參薯Dioscorea alata與山薯Dioscorea fordii關系親密，聚為另一分支，并位于發(fā)育樹基部。結論 ITS序列系統(tǒng)樹為澄清山藥類資源進化關系奠定了基礎，序列中豐富的變異位點為多基原山藥鑒別提供了科學依據。

Objective To provide scientific evidence for molecular identification and phylogenetic evolution by analyzing ITS sequences in 14 different germplasms from Dioscorea spp. Methods The internal transcribed spacer (ITS) regions were cloned by PCR amplification and sequenced bi-directionally. The ITS sequences were aligned using Clustal X software (version 1.83), the genetic distances were calculated via kimura 2-parameter (K2-P) model using Mega software (version 4.1), and the phylogenetic trees were constructed through the Neighbor-joining (NJ) and maximum parsimony (MP) methods. Results The length of ITS sequences obtained ranged from 558 to 594 bp, of which ITS1 was from 141 to 165 bp and ITS2 was from 146 to 158 bp. There were a lot of transitions and transversions in ITS sequences, and the transition/transversion bias among 14 different germplasms was 5.347. Both in ITS1 and in ITS2, 102 variable sites were further observed. The genetic distance among 14 different germplasms ranged form 0 to 0.517 2. The phylogenetic trees suggested that there are close genetic relationship among Dioscorea opposita, Dioscorea persimilis, and Dioscore japonica, they grouped closely into clade I; furthermore, Dioscorea alata and Dioscorea fordii also shared a closer genetic relationship and comprised another clade (Clade II). Conclusion The phylogenetic analyses based on ITS sequences can present a foundation for clearing the evolution of Dioscorea spp.; The variable bases can also provide reliable molecular evidences for identifying different genotypic germplasms of Dioscorea spp.

浙江省重點實驗室項目（2011E10015）；溫州市科技項目（N20100003）