药用植物华重楼(黑药花科)叶绿体全基因组研究

Complete Chloroplast Genome of the Medicinal Plant Paris polyphylla var. chinensis (Melanthiaceae)

摘要:

为探究华重楼(Paris polyphylla var. chinensis)的叶绿体基因组特征,利用叶绿体系统发育基因组学方法,对华重楼与其它百合目植物的叶绿体全基因组进行了比较。结果表明,华重楼的叶绿体全基因组长158307 bp,由4个区组成,包括2个反向重复区(IRA和IRB,27473 bp)、1个小单拷贝区(SSC,18175 bp)和1个大单拷贝区(LSC,85187 bp)。其叶绿体基因组有115个基因,包括81个编码蛋白质基因、30个转运RNA基因和4 个核糖体RNA基因。11种百合目植物的叶绿体全基因组的基因组成和基因顺序相似。华重楼的cemA基因是假基因,其起始密码子后有多聚核苷酸poly(A)及CA双核苷酸重复序列,编码序列中出现多个终止密码子, 且与北重楼(Paris verticillata)的cemA编码序列中的终止密码子位置不同。因此,华重楼叶绿体基因组比较保守;cemA结构及假基因化现象可能具有重要的进化与系统发育信息,其编码序列中的终止密码子可以区分华重楼和北重楼。

Abstract:

In order to understand the characters of chloroplast genome (cp genome) in Paris polyphylla var. chinensis, the chloroplast genome (cp genome) of P. polyphylla var. chinensis was compared with those of 10 species within Liliales by using phylogenomics methods based on complete chloroplast genomes. The results showed that the cp genome of P. polyphylla var. chinensis was 158307 bp in length and display a typical quadripartite structure including two inverted repeat regions (IRA and IRB, 27473 bp), one small singlecopy region (SSC, 18175 bp) and one large single-copy region (LSC, 85187 bp). It contained 115 unique genes, including 81 protein-coding genes, 30 tRNAs and 4 rRNAs. The genome structure, gene contents and arrangement of 10 Liliales species cp genomes were very similar. The cemA gene of P. polyphylla var. chinensis was pseudogene with poly(A) and CA SSR patterns after the start codon, and the loci of premature stop codons are different from those of Paris veticillata. In conclusion, the cp genome of P. polyphylla var. chinensis was conservative. The cemA structure and pseudogenization might play an important role in the evolution and phylogeny, and the location of the stop codons in cemA was useful for distinguishing P. polyphylla var. chinensis from P. veticillata.