摘要
选取7个叶绿体基因片段,其中3个编码区基因片段(matK,rps4 and rbcL-a)和4个非编码区基因片段(atpB-rbcL,atpF-H,psbK-Iandtrn H-psbA),一个线粒体基因片段(nad5)和一个核基因片段(ITS2),材料包括5个属14个种的74份样品。分析比较了6个基因片段的多样性、种内和种间的遗传距离、鉴别率等。结果显示,在使用单个片段时ITS2的鉴定效果最好,而atpB-rbcL则是叶绿体基因片段中鉴别能力最高的。使用组合片段的结果发现,两个基因片段组合的鉴别效果最好。通过NJ树的方法检验,atpB-rbcL+trn H-psbA和rbcL-a++trn H-psbA的鉴定成功率是64%,当再增加一个或两个基因片段时其鉴定效果并没有提高。本研究表明在植物中应用DNA条码需要用质体基因和核基因联合。
We compared the performances of the candidate loci for moss DNA barcoding and the primers used in amplifying the loci. Primers for three coded loci （matK,rps4 and rbcL-a） and four non-coded loci （atpB-rbcL,atpF-H,psbK-I and trnH-psbA） of the chloroplast genome,one from the mitochondrial genome （nad5）,and one from the nucleus genome （ITS2） were evaluated. Seventy-four samples representing 14 species belonging to five genera of Trachypodoaceae （or Meteoriaceae） were screened. All primers for matK and a pair of primers for trnH-psbA failed. Low successes were encountered with the primers for atpF-H and psbK-I. The primers for psbK-I produced several bands and the PCR products of atpF-H were difficult to sequence. The powers of the remaining six loci were compared using the variability,identification success and the resolutions. It was found that ITS2 is the most promising candidate for DNA barcoding for mosses. Among the chloroplast genes,atpB-rbcL exhibited the highest resolution. Although trnH-psbA is very variable,it is too short to be an ideal barcode alone. Combinations of chloroplast genes were also tried and Ps of both atpB-rbcL＋trnH-psbA and rbcL-a＋＋trnH-psbA were 64% using NJ method. More additions of loci did not increase the resolution. No barcoding gap exists for all these loci. Phylogenetic analyses were carried out prior to the DNA barcoding evaluation and some taxonomic problems do exist. This study exemplifies the necessity of correct species delimitation and the adoption of both plastid and nuclear loci in plant DNA barcoding.
出处
《云南植物研究》
CSCD
北大核心
2010年第3期239-249,共11页
Acta Botanica Yunnanica
基金
国家自然科技资源平台项目(2005DKA21401)
中科院植物所(KSCX2-YW-Z-0807)
