Single-gene FISH maps and major chromosomal rearrangements in Elymus sibiricus and E. nutans

Abstract

AbstractBackgroundChromosomal variations have been revealed in bothE. sibiricusandE. nutans, but chromosomal structural variations, such as intra-genome translocations and inversions, are still not recognized due to the cytological limitations of previous studies. Furthermore, the syntenic relationship between both species and wheat chromosomes remains unknown.ResultsFifty-nine single-gene fluorescence in situ hybridization (FISH) probes, including 22 single-gene probes previously mapped on wheat chromosomes and other newly developed probes from the cDNA ofElymusspecies, were used to characterize the chromosome homoeologous relationship and collinearity of bothE. sibiricusandE. nutanswith those of wheat. Eight species-specific chromosomal rearrangements (CRs) were exclusively identified inE. sibiricus, including five pericentric inversions in 1H, 2H, 3H, 6H and 2St; one possible pericentric inversion in 5St; one paracentric inversion in 4St; and one reciprocal 4H/6H translocation. Five species-specific CRs were identified inE. nutans, including one possible pericentric inversion in 2Y, three possible pericentric multiple-inversions in 1H, 2H and 4Y, and one reciprocal 4Y/5Y translocation. Polymorphic CRs were detected in three of the six materials inE. sibiricus, which were mainly represented by inter-genomic translocations. More polymorphic CRs were identified inE. nutans, including duplication and insertion, deletion, pericentric inversion, paracentric inversion, and intra- or inter-genomic translocation in different chromosomes.ConclusionsThe study first identified the cross-species homoeology and the syntenic relationship betweenE. sibiricus,E. nutansand wheat chromosomes. There are distinct different species-specific CRs betweenE. sibiricusandE. nutans, which may be due to their different polyploidy processes. The frequencies of intra-species polymorphic CRs inE. nutanswere higher than that inE. sibiricus. To conclude, the results provide new insights into genome structure and evolution and will facilitate the utilization of germplasm diversity in bothE. sibiricusandE. nutans.