扁果草叶绿体基因组特征分析

Characteristics of the chloroplast genome of Isopyrum anemonoides

摘要:

为探讨扁果草(Isopyrum anemonoides)叶绿体基因组特征及该属物种的系统发育关系，采用Illumina Hiseq高通量测序技术，对扁果草进行全基因组测序，组装、注释和完成扁果草叶绿体全基因组图谱绘制。结果显示，扁果草叶绿体全基因组总长161 034 bp，为典型的四分体结构，包含85个蛋白编码基因、37个转运RNA和8个核糖体RNA。共检测到44个散在重复序列和47个简单重复序列。此外，扁果草叶绿体基因组中共包含53 678个密码子，其中编码亮氨酸的密码子最多(5 251个)，编码色氨酸的密码子最少(712个)。共线性分析结果显示，扁果草与近缘种叶绿体基因组中不存在倒位或重排现象。系统发育分析表明，扁果草并未与该属的东北扁果草(I.manshuricum)聚在一个分支上，而是与假耧斗菜(Paraquilegia microphylla)有很近的亲缘关系。本研究为开展后续的扁果草属物种鉴定、系统发育研究提供基础资料。

Abstract:

In order to characterize the chloroplast genome and phylogenetic relationships of Isopyrum anemonoides, we performed Illumina Hiseq high-throughput sequencing to sequence the complete chloroplast genome of this plant and constructed a whole-genome map based on contig assembly and annotation. The chloroplast genome of I. anemonoides is 161 034 bp in length and has a typical tetrad structure, comprising 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The genome also contains a total of 44 dispersed repeat sequences and 47 simple sequence repeats. Among the genome's 53 678 codons, the largest proportion are leucine-encoding codons (5 251), whereas the smallest proportion encode tryptophan (712). Colinear analysis revealed an absence of inversions and rearrangements between I. anemonoides and related species at the chloroplast genome level. Whereas phylogenetic analysis indicated that I. anemonoides did not cluster in a clade with I. manshuricum, it did show a very close phylogenetic relationship with Paraquilegia microphylla. The findings of this study provide basic data that will contribute to further species identification and phylogenetic study of the genus Isopyrum.