Chloroplast (cp) genomes are considered important for the study of lineage-specific molecular evolution, population genetics, and phylogenetics. Our aim here was to elucidate the molecular evolution in cp genomes of species in the Dracunculus clade (Aroideae, Araceae). We report de novo assembled cp genomes for eight species from eight genera and also retrieved cp genomes of four species from the National Center for Biotechnology Information (NCBI). The cp genomes varied in size from 162,424 bp to 176,835 bp. Large Single Copy (LSC) region ranged in size from 87,141 bp to 95,475 bp; Small Single Copy (SSC) from 14,338 bp to 23,981 bp; and Inverted Repeats (IRa and IRb) from 25,131 bp to 32,708 bp. The expansion in inverted repeats led to duplication of ycf1 genes in four species. The genera showed high similarity in gene content and yielded 113 unique genes (79 protein-coding, 4 rRNA, and 30 tRNA genes). Codon usage, amino acid frequency, RNA editing sites, microsatellites repeats, transition and transversion substitutions, and synonymous and non-synonymous substitutions were also similar across the clade. A previous study reported deletion of ycf1, accD, psbE, trnL-CAA, and trnG-GCC genes in four Amorphophallus species. Our study supports conservative structure of cp genomes in the Dracunculus clade including Amorphophallus species and does not support gene deletion mentioned above. We also report suitable polymorphic loci based on comparative analyses of Dracunculus clade species, which could be useful for phylogenetic inference. Overall, the current study broad our knowledge about the molecular evolution of chloroplast genome in aroids.

叶绿体 (cp) 基因组被认为对于谱系特异性分子进化、种群遗传学和系统发育学的研究很重要。在这里我们的目的是阐明在该物种的基因组CP的分子进化龙蒿枝（Aroideae，天南星科）。我们报告了来自 8 个属的 8 个物种的从头组装的 cp 基因组，并且还从国家生物技术信息中心 (NCBI) 检索了 4 个物种的 cp 基因组。cp 基因组的大小从 162,424 bp 到 176,835 bp 不等。大单拷贝 (LSC) 区域的大小范围从 87,141 bp 到 95,475 bp；小单拷贝 (SSC) 从 14,338 bp 到 23,981 bp；和反向重复（IRa 和 IRb）从 25,131 bp 到 32,708 bp。反向重复的扩展导致ycf1 的重复四个物种的基因。该属在基因含量上表现出高度相似性，并产生了 113 个独特的基因（79 个蛋白质编码基因、4 个 rRNA 和 30 个 tRNA 基因）。密码子使用、氨基酸频率、RNA 编辑位点、微卫星重复、转换和颠换替换以及同义和非同义替换在进化枝中也相似。先前的一项研究报告了四种魔芋属物种中ycf1、accD、psbE、trnL-CAA和trnG-GCC基因的缺失。我们的研究支持包括魔芋在内的Dracunculus 进化枝中 cp 基因组的保守结构种，不支持上述基因缺失。我们还基于对Dracunculus clade 物种的比较分析报告了合适的多态位点，这可能对系统发育推断有用。总的来说，目前的研究拓宽了我们对植物叶绿体基因组分子进化的认识。