Rhododendron mariesii Hemsley et Wilson, 1907, a typical member of the family Ericaeae, possesses valuable medicinal and horticultural properties. In this research, the complete chloroplast (cp) genome of R. mariesii was sequenced and assembled, which proved to be a typical quadripartite structure with the length of 203,480 bp. In particular, the lengths of the large single copy region (LSC), small single copy region (SSC), and inverted repeat regions (IR) were 113,715 bp, 7,953 bp, and 40,918 bp, respectively. Among the 151 unique genes, 98 were protein-coding genes, 8 were tRNA genes, and 45 were rRNA genes. The structural characteristics of the R. mariesiicp genome was similar to other angiosperms. Leucine was the most representative amino acid, while cysteine was the lowest representative. Totally, 30 codons showed obvious codon usage bias, and most were A/U-ending codons. Six highly variable regions were observed, such as trnK-pafI and atpE-rpoB, which could serve as potential markers for future barcoding and phylogenetic research of R. mariesii species. Coding regions were more conserved than non-coding regions. Expansion and contraction in the IR region might be the main length variation in R. mariesii and related Ericaeae species. Maximum-likelihood (ML) phylogenetic analysis revealed that R. mariesii was relatively closed to the R. simsii Planchon, 1853 and R. pulchrum Sweet,1831. This research will supply rich genetic resource for R. mariesii and related species of the Ericaeae.

中文翻译：

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马里杜鹃完整叶绿体基因组序列和杜鹃花科相关物种的比较基因组学

 Rhododendron mariesii Hemsley et Wilson, 1907 是杜鹃花科的典型成员，具有宝贵的药用和园艺特性。本研究对R. mariesii完整的叶绿体（cp）基因组进行了测序和组装，结果证明其为典型的四部分体结构，长度为203,480 bp。特别是，大单拷贝区域（LSC）、小单拷贝区域（SSC）和反向重复区域（IR）的长度分别为113,715 bp、7,953 bp和40,918 bp。在151个独特基因中，98个是蛋白质编码基因，8个是tRNA基因，45个是rRNA基因。R. mariesiicp 基因组的结构特征与其他被子植物相似。亮氨酸是最具代表性的氨基酸，半胱氨酸是最低代表性的氨基酸。总共有30个密码子表现出明显的密码子使用偏差，并且大多数是A/U结尾的密码子。观察到 6 个高度可变的区域，例如 trnK-pafI 和 atpE-rpoB，它们可以作为未来 R. mariesii 物种的条形码和系统发育研究的潜在标记。编码区比非编码区更加保守。IR 区域的扩张和收缩可能是 R. mariesii 和相关杜鹃花科物种的主要长度变化。最大似然（ML）系统发育分析显示，R. mariesii 与 R. simsii Planchon, 1853 和 R. pulchrum Sweet,1831 相对接近。该研究将为杜鹃花科植物及相关物种提供丰富的遗传资源。