老芒麦和垂穗披碱草rDNA-ITS序列分析

rDNA-ITS sequence in Elymus sibiricus and E.nutans

分析了老芒麦和垂穗披碱草rDNA-ITS序列,为这两个种的鉴别提供分子指纹图谱,为系统发育提供分子生物学依据。结果表明,22份材料的ITS、ITS1、5.8S、ITS2序列长度均相同,依次为604bp、222bp、164bp、218bp,GC含量依次为62.25%～63.08%,62.16%～63.06%,59.76%,64.22%～65.60%。除5.8S外,碱基位点都有不同程度的变化,一些变异位点有明显的种性变异规律,可作为老芒麦和垂穗披碱草种质DNA指纹特异鉴别位点。7个ITS序列的同源性98.7%～99.8%,遗传分歧0.2～1.3,具有保守性,为非近期分化类群。系统发育分析表明不同来源地的同种材料,差异主要表现在DNA变化快慢及碱基替换数,但相同的种归为一类,进一步反映了种内的遗传稳定性。

Analysis of ITS sequences of Elymus sibiricus and E.nutans will provide useful information for germplasm DNA fingerprint identification and phylogeny.The results showed that the lengths of ITS,ITS1,5.8S and ITS2 in 22 accessions tested were identical,which were 604bp,222bp,164bp,and 218bp,and GC contents were 62.25%-63.08%,62.16%-63.06%,59.76%,and 64.22%-65.60%,respectively.Except for 5.8S,base sites varied to some extent.Some variable sites were species-specific,which can be used as DNA molecular markers of E.sibiricus and E.nutans.The identity of the seven ITS sequences ranged from 98.7% to 99.8%,and the divergence was 0.2-1.3.These sequences were conserved and not recent differentiated groups.Phylogenetic analysis indicated that the difference for various sources of the same species was the speed of DNA changes and the number of base substitution.However,the same species were classified in the same group,further reflecting the intraspecific genetic stability.