白豆杉的叶绿体基因组结构与系统进化分析

以红豆杉科单种属植物白豆杉(Pseudotaxus chienii(W.C.Cheng)W.C.Cheng)为材料,进行叶绿体全基因组测序,并对其基因含量、结构及重复序列进行分析。结果显示:白豆杉叶绿体基因组不包含典型的反向重复区,基因组全长为130427 bp,共编码116个基因,包含83个蛋白编码基因、4个rRNA基因和29个tRNA基因;其叶绿体基因组包含44个简单重复序列和11个串联重复序列。系统发育关系分析结果表明,红豆杉科和三尖杉科互为姐妹群;在红豆杉科内部,白豆杉属(Pseudotaxus)与红豆杉属(Taxus)亲缘关系较近,榧树属(Torreya)与穗花杉属(Amentotaxus)聚为一支。红豆杉科8种植物的叶绿体基因组结构比较结果显示,红豆杉属与白豆杉属的叶绿体基因组结构基本一致,红豆杉科其他属之间存在不同程度的重排。研究结果表明采用叶绿体基因组数据可以较好地解决红豆杉科植物的系统发育关系。

Structure and phylogenetic analysis of the Pseudotaxus chienii (W. C. Cheng) W. C. Cheng chloroplast genome

The complete chloroplast genome sequence of Pseudotaxus chienii (W. C. Cheng) W. C. Cheng was determined in this study. Gene content, genome structure, and repeat sequences were also analyzed. Results revealed that the chloroplast genome did not contain typical inverted repeats. The genome was 130 427 bp in length, containing 83 protein coding, four rRNA, and 29 tRNA genes. Forty-four simple sequence repeat loci and 13 tandem repeats were identified in the chloroplast genome of P. chienii. Phylogenetic analysis supported Taxaceae as sister to Cephalotaxaceae. Within Taxaceae, Pseudotaxus and Taxus formed a monophyletic group, while Torreya and Amentotaxus clustered together. The alignment of eight Taxaceae species showed that the chloroplast genome organization of P. chienii was highly similar to that of Taxus, while rearrangement also existed between different genera of Taxaceae. Thus, these results indicate that chloroplast genome data can better solve the phylogenetic relationships of Taxus plants.