相近石韦叶绿体基因组学分析

目的:测定相近石韦Pyrrosia assimilis叶绿体基因组,分析其序列特征并探讨相近石韦本草基因组学研究。方法:应用高通量测序技术对相近石韦进行了叶绿体全基因组测序,利用生物信息学方法分析其结构特征和系统发育关系。结果:相近石韦叶绿体基因组呈环形双链结构,全长154 964 bp,鸟嘌呤和胞嘧啶(GC)总量41. 2%;共注释到131个基因,包括88个蛋白编码基因,35个转运RNA(tRNA)基因和8个核糖体RNA(rRNA)基因;共检测到43个散在重复序列和56个简单重复序列(SSR);编码亮氨酸的密码子使用频率最高,编码色氨酸的密码子数最少;叶绿体基因组全局比对分析筛选出5个高变异区(psb A,rrn16,pet A-psbJ,ndh C-trnM和psb M-petN);系统发育树显示相近石韦与波氏石韦P. bonii亲缘关系较近。结论:相近石韦叶绿体基因组中非编码区变异高于编码区,大单拷贝区(LSC)和小单拷贝区(SSC)变异大于反向重复区(IR),筛选出的5个高变区可作为石韦属物种鉴定的候选DNA条形码。相近石韦的叶绿体基因组学研究为其他石韦属药用植物在分子鉴定、遗传基因转化、抗性蛋白表达及次生代谢途径解析等方面的研究提供了参考。

Chloroplast Genomic Analysis of Pyrrosia assimilis

Objective: The complete chloroplast genome of Pyrrosia assimilis was sequenced, its sequence characteristics was analyzed and herbgenomics of P. assimilis was discussed. Method: Its complete chloroplast genome sequence was determined through high-throughput sequencing technology, and its structural characteristics and phylogenetic relationships were analyzed by bioinformatics. Result: The chloroplast genome of P. assimilis was a circular double-chain structure with a total length of 154 964 bp, and the total content of guanine and cytosine (GC) was 41.2%. A total of 131 genes were annotated, including 88 protein-coding genes, 35 transfer RNA (tRNA) genes and 8 ribosomal RNA (rRNA) genes. A total of 43 dispersed repetitive sequences and 56 simple sequence repeats (SSRs) were detected. The frequency of codon encoding leucine was the highest, while the number of codon encoding tryptophan was the lowest. Five highly divergent regions (psbA, rrn16, petA-psbJ, ndhC-trnM, and psbM-petN) were screened, phylogenetic analysis showed that P. assimilis was closely related to P. bonii. Conclusion: Comparative analysis of the complete chloroplast genome of P. assimilis reveals that non-coding regions exhibited a higher divergence than the coding regions, the large single copy region (LSC) and small single copy region (SSC) are more divergent than the reverse repeat region (IR), the selected five highly variable regions can be used as specific DNA barcodes for identification of Pyrrosia species. Study on the chloroplast genome of P. assimilis can provide a reference for the molecular identification, genetic transformation, expression of resistance protein and secondary metabolism pathway analysis of other Pyrrosia medicinal plants.