基因条码在条斑紫菜(Pyropia yezoensis)不同品系间种质鉴定中的适用性

Applicability of DNA Barcoding in the Identification of Different Strains in Pyropia yezoensis

中文关键词: 条斑紫菜  基因条码  品系  种质鉴定

英文关键词: Pyropia yezoensis  DNA barcodings  Strains  Germplasm identification

中文摘要:

      为寻找适宜的条斑紫菜(Pyropia yezoensis)品系间种质分子标记鉴定法，利用4种基因条码(RUBISCO Spacer、UPA、Cox2-3和ITS-5.8S)对产自中国和日本的6个条斑紫菜品系的亲缘关系进行了分析研究。结果显示，在6个条斑紫菜品系中，上述4种基因条码的序列同源性较高，同源性为97.8%–100%，其中，RUBISCO Spacer序列的同源性为100%。UPA序列的同源性分析结果显示，在中国产的LS、B4、HT和TM18品系中，该序列完全相同，但与日本产的GT和ROS-2两个品系的序列有差异，该序列的同源性为99.2%。在6个品系中，Cox2-3和ITS-5.8S序列的同源性相对较低，分别为97.8%–99.2%和98.4%–99.8%。根据UPA、Cox2-3和ITS-5.8S基因条码通过邻接法构建的系统进化树显示，依据ITS-5.8S和UPA序列均能分别区分中国产的4个品系(LS、B4、HT和TM18)与日本产的两个品系(GT和ROS-2)，分别形成两个大分支，其聚类结果与实际亲缘关系一致。但利用ITS-5.8S序列均能对中国产的4个品系和日本产的两个品系进行再区分，而利用UPA序列却无法对中国产的4个品系进行再区分，只能区分日本产的两个品系。使用Cox2-3序列则将GT、ROS-2、LS和TM18这4个品系聚成一个大分支，其聚类结果与实际亲缘关系不一致。上述结果说明，利用ITS-5.8S序列对本研究的6个条斑紫菜品系进行种质鉴定，效果最好。

英文摘要:

      In order to find out an effective method to identify Pyropia yezoensis germplasm, we tested the efficacy of four common DNA barcodings—RUBISCO Spacer, UPA, Cox2-3, and ITS-5.8S—in determining the genetic relationships between six strains of P. yezoensis from China and Japan. The four DNA barcodings showed high sequence homologies varying from 97.8% to 100%, and the homology of RUBISCO Spacer was 100%. Four Chinese strains (LS, B4, HT, and TM18) shared the same UPA sequence. However, the barcoding was different from that of the Japanese strains GT and ROS-2 and the homology was 99.2%. The homologies of Cox2-3 and ITS-5.8S sequences were 97.8%-99.2% and 98.4%-99.8% respectively, which were lower than those of RUBISCO Spacer and UPA. Phylogenesis of UPA, Cox2-3 and ITS-5.8S sequences revealed that the four Chinese strains clustered into one branch according to their UPA and ITS-5.8S sequences, whereas the two Japanese strains belonged to another branch. These results were consistent with their actual relationships. Moreover, the four Chinese strains could be further distinguished according to their ITS-5.8S sequences, but were identified as in the same branch with the Cox2-3 barcoding. The results confirmed that ITS-5.8S was the most effective barcoding for identifying P. yezoensis strains in this study