Chloroplast phylogenomics to resolve the phylogenetic relationships of major taxonomic groups in bryophytes

对7种苔藓、2种苔类和1种角藻的叶绿体基因组进行了新测序。叶绿体基因组的比较表明，鳞毛藻是苔藓中最大的cp基因组，其基因含量与地钱和金鱼藻的基因含量几乎相同。进化过程中的一些基因丢失事件被认为是考虑主要苔藓系之间关系的有效方法。此外，我们首次在泥炭苔藓中检测到叶绿体基因组的线形和环状DNA分子。一些较大的分子似乎是从单个基因组的多聚体构象中衍生出来的。在一些开花植物中也发现了线性和多聚体分子的存在。这种叶绿体基因组的结构可塑性似乎在陆地植物中是进化保守的。

Chloroplast genomes of seven mosses, two liverworts and one hornworts species were newly sequenced. Comparison of the chloroplast genomes showed that T. lepidozioides had the largest cp genome in the mosses and the gene content was almost identical to those of liverworts and hornworts. Some gene-loss events through the evolution were indicated to be effective for considering the relationships of major moss lineages.In addition, we firstly detected linear and circular DNA molecules of chloroplast genome in a Sphagnum moss. Some larger molecules seem to be derived from multimeric conformations of single genomes. The occurrence of linear and multimeric molecules also have been known in some flowering plants. Such structural plasticity of the chloroplast genome seems to be evolutionary conserved across land plants.