English

Abstract

Due to outstanding characteristics such as stress resistance and high biomass production, Elymus sibiricus (StH genomes) and E. nutans (StHY genomes) are regarded as ecologically important perennial bunchgrass species belonging to Elymus genus of tribe Triticeae (Poaceae), which were widely used to promote the restoration of degraded grassland in the eastern Tibetan Plateau. In this study, the complete chloroplast (cp) genome of E. sibiricus and E. nutans were sequenced and annotated with de novo analysis, to clarify their inter-species variation and their evolutionary relationships with relative species. The result showed that both two whole cp genomes shared a typical quadripartite structure, the cp genome length of E. sibiricus and E. nutans were 135,075 bp and 135,060 bp, respectively. Three genes tRNA-CGA, tRNA-CGU, and tRNA-CGU were unique in E. sibiricus while the gene ycf1 (hypothetical chloroplast reading frame no. 1) was only found in E. nutans. The identification of hotspot regions (tRNA-GUC~psbM, tRNA-UAA~ndhJ, rbcL~psaI, rpl33~rps18) between the two cp genomes would be pertinent to the development of barcode marker of these two Elymus species. Comparative cp genome analysis and phylogenetic relationships further confirmed that Pseudoroegneria were putative matrilineal donors of St genome of Elymus species at plastome level. Whole cp genomes could be used as an effective barcode for species identification or for developing specific markers, which is essential useful for the evolutionary history and conservation of Elymus species. © 2021 Friends Science Publishers