Natural and Medical Sciences Research Centre, University of Nizwa, 616, Nizwa, Oman.
Department of Engineering Technology, University of Houston, Sugar Land, TX, 77479, USA.
Sci Rep. 2022 Oct 6;12(1):16787. doi: 10.1038/s41598-022-20304-6.
Dracaena (Asparagaceae family) tree is famous for producing "dragon blood"-a bioactive red-colored resin. Despite its long history of use in traditional medicine, little knowledge exists on the genomic architecture, phylogenetic position, or evolution. Hence, in this study, we sequenced the whole chloroplast (cp) genomes of D. serrulata and D. cinnabari and performed comparative genomics of nine genomes of the genus Dracaena. The results showed that the genome sizes range from 155,055 (D. elliptica) to 155,449 (D. cochinchinensis). The cp genomes of D. serrulata and D. cinnabari encode 131 genes, each including 85 and 84 protein-coding genes, respectively. However, the D. hokouensis had the highest number of genes (133), with 85 protein coding genes. Similarly, about 80 and 82 repeats were identified in the cp genomes of D. serrulata and D. cinnabari, respectively, while the highest repeats (103) were detected in the cp genome of D. terniflora. The number of simple sequence repeats (SSRs) was 176 and 159 in D. serrulata and D. cinnabari cp genomes, respectively. Furthermore, the comparative analysis of complete cp genomes revealed high sequence similarity. However, some sequence divergences were observed in accD, matK, rpl16, rpoC2, and ycf1 genes and some intergenic spacers. The phylogenomic analysis revealed that D. serrulata and D. cinnabari form a monophyletic clade, sister to the remaining Dracaena species sampled in this study, with high bootstrap values. In conclusion, this study provides valuable genetic information for studying the evolutionary relationships and population genetics of Dracaena, which is threatened in its conservation status.
龙血树（天门冬科）因产生具有生物活性的红色树脂而闻名，这种树脂被称为“龙血”。尽管它在传统医学中的应用历史悠久，但人们对其基因组结构、系统发育位置或进化知之甚少。因此，在这项研究中，我们对 1 种弯叶龙血树（Dracaena serrulata）和 1 种红海血树（Dracaena cinnabari）的整个叶绿体（cp）基因组进行了测序，并对 9 种 Dracaena 属植物的基因组进行了比较基因组学分析。结果表明，基因组大小范围为 155055（D.elliptica）至 155449（D.cochinchinensis）。弯叶龙血树和红海血树的 cp 基因组共编码 131 个基因，分别包含 85 个和 84 个蛋白编码基因。然而，D.hokouensis 的基因数量最多（133 个），其中 85 个为蛋白编码基因。同样，在弯叶龙血树和红海血树的 cp 基因组中分别鉴定出约 80 和 82 个重复序列，而在 D.terniflora 的 cp 基因组中检测到的重复序列最多（103 个）。弯叶龙血树和红海血树的 cp 基因组中简单序列重复（SSR）的数量分别为 176 和 159 个。此外，对完整 cp 基因组的比较分析显示出高度的序列相似性。然而，在 accD、matK、rpl16、rpoC2 和 ycf1 基因以及一些内含子间隔区观察到一些序列分歧。系统发育分析表明，弯叶龙血树和红海血树形成一个单系分支，与本研究中采样的其余 Dracaena 物种亲缘关系最近，支持率较高。总之，这项研究为研究龙血树的进化关系和群体遗传学提供了有价值的遗传信息，龙血树的保护状况受到威胁。
