Molecular characterization of the St genome in Pseudoroegneria species and their relationships to the Y genome in Elymus species, and origin of Elymus caninus

Abstract

Although five basic genomes (St, H, Y, P and W ) have so far been identified in species of the genus Elymus , the origin of the Y genome in species with an StY genome is still unknown and under debate. Previous studies suggested that the St and Y genomes may share a common progenitor genome. To test this hypothesis and to avoid under-sampling biases, we analyzed extensive accessions of diploid Pseudoroegneria (St) species using molecular markers. The results showed that diploid St-genome species have a high level of nucleotide variation, especially in P. spicata , and rejected the suggestion of the same origin of the St and Y genomes. In addition, the study on the origin of Elymus caninus clearly confirmed the StH genome constitution in E. caninus and indicated that both the St and H genomes in this species have multiple origins.