红花木棉与黄花木棉核糖体 DNA 分子系统发育研究

摘要

The ribosome rDNA ITS sequences and phylogenetic tree of 14 Bombax malabaricum (red flower or yellow flower species) from 14 species of Bombax malabaricum genus were analyzed and established by adopting DNA extraction and PCR production. The two genus (Ceiba Mill.emend.Gaertn.and Ochroma Swartz) which have close genetic relations to Bombax were selected as the out-groups. And then, based on maximum likelihood analysis, maximum parsimony analysis and Bayesian inference, the molecular phylogenetic reconstruction for yellow kapok and red kapok individuals of Bombax genus were carried out. The results show that the botanical descriptions of yellow kapok and red kapok are basically consistent, the ribosome rDNA ITS sequences similarity between the tested materials and the recorded B. malabaricum was 99 %, the yellow kapok and red kapok had close genetic relationship with B. ceiba and B. insigne. RNA secondary structure simulation analysis showed the genetic variation in 5.8 sRNA was extremely small, the main genetic variation were in ITS1-ITS2 non-coding sequence. The results therefore implied that the characters of yellow kapok and red kapok produced was not genus or species differences, but caused by environmental mutagenesis; The comprehensive evaluations on main botanical characters and molecular biology of gene sequences of the two kapok species conducted, thus verifying that yellow kapok and red kapok belong to the same species.%以开红花和黄花木棉属木棉 Bombax malabaricum 的14株个体的核糖体 DNA ITS 序列测序结果，构建了系统发育树，并选取与木棉属较近亲缘关系的吉贝属 Ceiba Mill.emend.Gaertn.、轻木属 Ochroma Swartz 的种作为外类群，基于 Maximum likelihood analysis（最大似然法）、Maximum parsimony analysis（最大简约法）和Bayesian inference（贝叶斯方法）对木棉属红花和黄花的木棉个体植株进行分子系统发育重建。结果表明，开红花木棉和开黄花木棉的植物学特征描述基本一致，来源于不同地点或同一地点供试木棉植株分子序列与 Genbank中记录的木棉的 ITS 全长序列相似度为99%，与同属的 Bombax buonopozense 亲缘关系较近，并且与 ITS 序列对红花木棉和黄花木棉所有物种以100%的 Bootstrap 聚在一起。对两者的主要植物学性状和分子生物学基因序列综合评价，确认红花木棉和黄花木棉同属一个种。