Elymus nutans is an important forage and ecological restoration herbage in the Qinghai-Tibet Plateau, which is an allohexaploid species with the StStYYHH genomes. Previous studies suggested that Pseudoroegneria is the maternal genome donor to E. nutans, but exactly which Pseudoroegneria species is still unknown. Here, we report the complete chloroplast (cp) genome sequence of two E. nutans from the Qinghai-Tibet and five Pseudoroegneria species. The cp genomes of the seven samples ranged narrowly from 134,924 bp to 135,142 bp in size, comprising inverted repeats of 20,808–20,814 bp, single-copy regions of 80,536–80,754 bp (LSC) and 12,762–12,772 bp (SSC). It encoded 111 total genes, of which 78 protein-coding genes, 29 tRNA genes, and four rRNA genes. A comparative cp genome analysis and characteristic junctions of St-containing species revealed that the gene content and organization were conserved, but differences were still found in sequence variation and border regions. Further, the Bayesian inference (BI) phylogenetic tree using the whole chloroplast genome sequence demonstrated that P. cognata might be the most likely St genome donor of E. nutans in the Qinghai-Tibet Plateau, followed by P. strigosa. However, whether E. nutans has other maternal genomes still needs further research.

中文翻译：

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基于叶绿体基因组的青藏高原Elymus nutans母源基因组分析

Elymus nutans是青藏高原重要的牧草和生态恢复牧草，是具有StStYYHH基因组的异源六倍体物种。以前的研究表明，假单胞菌是E. nutans的母体基因组供体，但究竟是哪种假单胞菌物种仍然未知。在这里，我们报告了来自青藏地区的两个E. nutans和五个Pseudoroegneria的完整叶绿体 (cp) 基因组序列物种。七个样本的 cp 基因组的大小范围从 134,924 bp 到 135,142 bp，包括 20,808–20,814 bp 的反向重复、80,536–80,754 bp (LSC) 和 12,762–12,772 bp (SSC) 的单拷贝区域。它总共编码了 111 个基因，其中 78 个蛋白质编码基因、29 个 tRNA 基因和 4 个 rRNA 基因。比较 cp 基因组分析和含St物种的特征连接表明，基因含量和组织是保守的，但在序列变异和边界区域仍然存在差异。此外，使用整个叶绿体基因组序列的贝叶斯推理 (BI) 系统发育树证明P. cognata可能是E. nutans最可能的St基因组供体在青藏高原，其次是P. strigosa。然而，E. nutans是否有其他母体基因组仍需进一步研究。