新变种上犹杜鹃的ITS分子标记证据分析

Analysis of the evidences of ITS from a new variety Rhododendron seniavinii var.shangyounicum

关键词:  杜鹃属  新变种  ITS证据

Key words:  Rhododendron  new variety  evidences of ITS

摘要:

对杜鹃花科杜鹃属的新变种上犹杜鹃进行了ITS分子标记分析。结果表明:(1)上犹杜鹃与原变种毛果杜鹃在系统树上没有聚合为一支;(2)上犹杜鹃ITS序列密码子第二位上的G+C含量与原变种毛果杜鹃差异明显,而且编码位上的G+C含量(G+Cc)也与原变种毛果杜鹃有差异;(3)上犹杜鹃与原变种毛果杜鹃的形态特征有明显的区别,并具间断性特征;(4)密码子偏向性指数CBI分析正好反映了上犹杜鹃处于“变种”等级阶段的特点。基于这些证据,认为上犹杜鹃处理为种以下等级“变种”比较合理。

Abstract:

Rhododendron seniavinii var.shangyounicum is a new variety,which belongs to the family Ericaceae and genus Rhododendron. As to make classification of this new variety more true,many evidences of ITS has been studied in this paper and the results are as follows:(1)Based on the strict consensus and most parsimonious tree of ITS sequences,Rh.seniavinii var.shangyounicum has not been clustered with Rh.seniavinii var.seniavinii;(2)G+C content at second codon positions(G+C2)is more different Rh.seniavinii var.shangyounicum and Rh.seniavinii var.seniavinii,and G+C content at coding positions(G+Cc)also is different between them;(3)morphologic characters between this two taxa is clearly different by some intermittent characters;(4)Codon Bias Index CBI shows features of a new variety Rh.seniavinii var.shangyounicum which is in evolving. According to the evidences above,it is reasonable that Rh.seniavinii var.shangyounicum should be treated as a variety.