Phylogenetic analysis of the maternal genome of tetraploid StStYY Elymus (Triticeae: Poaceae) species and the monogenomic Triticeae based on rps16 sequence data

摘要

Although there have been several studies on the maternal genome donor of StStYY Elymus species, due to either the lack of inclusion of all the Triticeae diploid species or limited number of StY species used in the previous studies, it is necessary to investigate the origin of the maternal genome of the StStYY Elymus species with comprehensive samples of Triticeae diploid species. In this study we analyzed 18 tetraploid StStYY Elymus species along with 27 diploid Triticeae species using chloroplast gene encoding ribosomal protein S16 (rps16) in an attempt to identify the maternal genome donor of StStYY Elymus species. The rps16 data indicates that Pseudoroegneria is the maternal genome donor of StStYY Elymus species. A close relationship of the chloroplast of Thinopyrum and Dasypyrum with the St genome is found which leaves the possibility that Thinopyrum and Dasypyrum may have contributed to the chloroplast genome in StStYY species. We also analyzed the cpDNA phylogeny for the monogenomic genera. Psathyrostachys juncea is at the base of the Triticeae tree, while the rest of the Triticeae species forms a well supported clade with a 91% bootstrap value. Triticum monococcum, Secale cereale, Heteranthelium piliferum and all the Aegilops species form a clade. A very similar chloroplast genome between Agropyron and Eremopyrum is detected. Our rps16 data supports the placement of Henrardia within the Triticeae in a Henrardia + Eremopyrum clade.