Variations in abundance of 2 repetitive sequences in Leymus and Psathyrostachys species

Abstract

The Ns genome of the genus Psathyrostachys is a component of the polyploid genome in the genus Leymus. Using fluorescence in situ hybridization (FISH), the occurrence and abundance of 2 tandem repetitive sequences from Leymus racemosus (Lam.) Tzvelev, pLrTaiI-1 (TaiI family) and pLrPstI-1 (1 class of 350-bp family), were assayed in 4 species of the genera Psathyrostachys and Leymus. The pLrPstI-1 sequence was absent in all 4 Psathyrostachys species. While P. fragilis and P. huashanica did not have the pLrTaiI-1 sequence, 15 accessions of P. juncea and 2 accessions of P. lanuginosa had pLrTaiI-1 sites ranging in number from 7 to 16 and from 2 to 21, respectively. The numbers of pLrTaiI-1 and pLrPstI-1 sites were 1-24 and 0-30, respectively, in L. ramosus; 2-31 and 5-36 in L. racemosus; 0-4 and 0 in L. mollis; 2-9 and 24-27 in L. secalinus. The FISH assay on pLrTaiI-1 was successfully converted to a sequence-tagged-site polymerase chain reaction (STS-PCR) test using a primer pair designed from the sequence of this repetitive DNA. Seventy-three accessions representing 27 Leymus species were assayed for the abundance of pLrTaiI-1 by STS-PCR. With a few exceptions of uniformity in some accessions, nearly all Leymus species observed were heterogeneous for the abundance of pLrTaiI-1 sequence and no Leymus species was totally devoid of this repetitive sequence. These findings may have significance for the understanding of phylogeny, nature of polyploidy, adaptive ranges, and breeding potential of Leymus species.

Phylogeny and evolutionary history of Leymus(Triticeae; Poaceae) based on a single-copy nuclear gene encoding plastid acetyl-CoA carboxylase

“…Psathyrostachys is the Ns haplome donor genus, which contains approximately eight diploids (NsNs) or tetraploids (NsNsNsNs) speices distributed in the Middle East, central Asia, and northern China [ 3 ]. Based on DNA hybridization and FISH analyses, Wang et al [ 54 ] suggested that the Ns genome of Leymus species may be originated from Psa. juncea and Psa.…”

Development and annotation of perennial Triticeae ESTs and SSR markers

“…North American Elymus species contain the St and H genomes (Mason-Gamer et al 2002), with the St genome derived from a perennial diploid, Pseudoroegneria spicata (Pursh) A. Löve, and the H genome derived from an unknown Hordeum species (Dewey 1971). Leymus species contain the Ns and Xm genomes, where the Ns genome is derived from the genus Psathyrostachys and the Xm genome remains uncharacterized (Zhang and Dvorak 1991;Wang et al 2006).…”

Efficient anchoring of alien chromosome segments introgressed into bread wheat by new Leymus racemosus genome-based markers

“…Also, the transferred markers were found to be reasonably polymorphic in wheat (Table 6 ), suggesting their suitability for characterizing wheat genotypes with alien chromosomes from the three genomes. The genera of these species, because of their recognition as profitable forage grasses and gene mines for hexaploid breeding, have received fair research attention [ 13 , 14 , 23 , 25 , 48 – 50 ]. However, their genomes have not yet been sequenced, leaving breeders with the option of transferring markers from evolutionary closely related species to analyze their genomes and wheat genotypes carrying their chromosomes.…”