Chloroplast genome evolution in early diverged leptosporangiate ferns.
Chloroplast genome evolution in early diverged leptosporangiate ferns.
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DOI：
10.14348/molcells.2014.2296
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发表时间：
2014-05
影响因子：
3.8
通讯作者：
Kim KJ
中科院分区：
文献类型：
--
作者：
Kim HT;Chung MG;Kim KJ
本研究对三种早期分化的细囊蕨类植物的叶绿体基因组序列进行了分析，以了解蕨类植物谱系的基因组进化。薇菜属植物薇菜（Osmundacinnamomea）cp基因组全序列为142，812 bp。cp基因组结构与厚囊蕨相似。细囊蕨cp基因组中常见的基因/内含子缺失在O.肉桂此外，CP基因组中的推定RNA编辑位点在O. cinnamomea，即使该网站经常被预测存在于leptosporangiate蕨类植物。灰叶双翅草（Diplopterygium glaucum）（Gleicheniales）的完整cp基因组序列为151，007 bp，与O.肉桂在反转断点附近检测到几个重复序列。海金沙（Lygodiumjaponicum，Schizaeales）cp基因组全序列为157，142 bp，并检测到rpoC 1内含子的缺失。这种内含子丢失是海金沙属的所有研究物种所共有的。蕨类植物的GC含量和有效密码子数（ENC）与种子植物相比差异显著。早期分歧leptosporangiate蕨类植物的ENC值之间的厚囊和核心leptosporangiate蕨类植物的中间水平。然而，我们基于所有cp基因序列的系统发育树清楚地表明，O。Cinnamomea（Osmundales）和厚囊蕨是合形，而不是联会。因此，我们的数据是一致的观点，贯众是一个独特的早期分歧的谱系在leptosporangiate蕨类。
In this study, the chloroplast (cp) genome sequences from three early diverged leptosporangiate ferns were completed and analyzed in order to understand the evolution of the genome of the fern lineages. The complete cp genome sequence of Osmunda cinnamomea (Osmundales) was 142,812 base pairs (bp). The cp genome structure was similar to that of eusporangiate ferns. The gene/intron losses that frequently occurred in the cp genome of leptosporangiate ferns were not found in the cp genome of O. cinnamomea. In addition, putative RNA editing sites in the cp genome were rare in O. cinnamomea, even though the sites were frequently predicted to be present in leptosporangiate ferns. The complete cp genome sequence of Diplopterygium glaucum (Gleicheniales) was 151,007 bp and has a 9.7 kb inversion between the trnL-CAA and trnV-GCA genes when compared to O. cinnamomea. Several repeated sequences were detected around the inversion break points. The complete cp genome sequence of Lygodium japonicum (Schizaeales) was 157,142 bp and a deletion of the rpoC1 intron was detected. This intron loss was shared by all of the studied species of the genus Lygodium. The GC contents and the effective numbers of co-dons (ENCs) in ferns varied significantly when compared to seed plants. The ENC values of the early diverged leptosporangiate ferns showed intermediate levels between eusporangiate and core leptosporangiate ferns. However, our phylogenetic tree based on all of the cp gene sequences clearly indicated that the cp genome similarity between O. cinnamomea (Osmundales) and eusporangiate ferns are symplesiomorphies, rather than synapomorphies. Therefore, our data is in agreement with the view that Osmundales is a distinct early diverged lineage in the leptosporangiate ferns.