Identifying the genome of wood barley Hordelymus europaeus (Poaceae: Triticeae)

Abstract

Wood barley, Hordelymus europaeus, was compared with other Triticeae species by Southern and fluorescence in situ hybridisation using total genomic DNA and repetitive sequences as probes. On Southern blots, the total genomic probe from H. europaeus hybridised strongly to DNA of its own species and to Leymus and Psathyrostachys, indicating the presence of Ns genome in H. europaeus. Furthermore, the total genomic probe from P. fragilis hybridised to DNA of H. europaeus as much as to all of the Psathyrostachys and Leymus species examined. Ns genome-specific DNA sequences isolated from L. mollis (pLmIs1, pLmIs44 and pLmIs53) hybridised essentially to H. europaeus and all of the species of Leymus and Psathyrostachys. Chromosomal localization of these clones on H. europaeus confirmed the presence of Ns genome-specific DNA on all chromosomes, indiscriminately. Under moderate hybridisation stringency the Ns genome-specific probes, together with repetitive sequences pTa71 and pAesKB7, produced species-specific RFLP banding profiles on Southern blots. A phenetic tree based on these profiles revealed a distinct Ns species cluster within the Triticeae, represented by Leymus and Psathyrostachys species. Hordelymus europaeus belonged to this Ns cluster. Chromosomal mapping of the 18S-25S and the 5S ribosomal genes, together with the repetitive sequence pLrTaiI, corroborated that H. europaeus was most probably related to Leymus, especially the European/Eurasian members of sect. Leymus. In an attempt to identify the genome of H. europaeus, different approaches were employed; the results clearly showed that wood barley had the Ns basic genome and nothing else.

Sequence variation at the three chloroplast loci (matK, rbcL, trnH-psbA) in the Triticeae tribe (Poaceae): comments on the relationships and utility in DNA barcoding of selected species

“…The close similarity to the Ns genome was later confirmed by Petersen and Seberg (2008). Moreover, the southern and fluorescence in situ hybridization indicated that H. europaeus is an autotetraploid carrying only the Ns genome (Ellneskog-Staam et al 2006). The chloroplast non-coding trnS-psbC sequences of Hordelymus are similar to those of T. caput-medusae subsp.…”

Phylogeographic pattern of the European forest grass species Hordelymus europaeus: cpDNA evidence

“…The relationships of the genus to other taxa of the family Poaceae remain unclear (Mizianty et al, 2005(Mizianty et al, , 2007. Molecular studies (based on both nuclear and chloroplast DNA analyses) suggest an autotetraploid (or segmental allotetraploid) origin most closely related to the genus Leymus (tribe Triticae) (Ellneskog-Staam et al, 2006;Bouchenak-Khelladi et al, 2008).…”

“…It is classified as a diagnostic species for the Eu-Fagenion suballiance (herb-rich beech forests) and Atropion alliance (vegetation of forest clearings on eutrophic soils) (Chytrý and Tichý , 2003;Jarolímek andŠibík, 2008). H. europaeus is a caespitose perennial grass forming only short rhizomes and a tetraploid wind-pollinated species with considerable self-fertilisation ability (Tutin, 1980;Kubá t, 2002;Ellneskog-Staam et al, 2006;Mizianty et al, 2007).…”

Maternal origin, genome constitution and evolutionary relationships of polyploid Elymus species and Hordelymus europaeus

“…Recently, genomic southern hybridization data indicated the presence of an Ns genome highly homologous to that of Psathyrostachys and Leymus and rejected the presence of H, T, E or St genomes in Hor. europaeus (Ellneskog-Staam et al 2006). Phylogenetic analyses of sequence data from two plastid genes (rbcL and ndhF) provided substantial support for the progenitor of Psathyrostachys as female genome donor of Hordelymus (Petersen and Seberg 2008).…”

“…However, genomic hybridization suggested presences of Ns genome and absence of T genome in Hor. europaeus (Ellneskog-Staam et al 2006). Recently, Petersen and Seberg (2008) reported Psathyrostachys as female genome donor of Hordelymus.…”