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Roegneria is a polyploid perennial genus in the tribe Triticeae. Some species of Roegneria are morphologically similar to genus Elymus and have been classified in Elymus. To investigate the delimitation and phylogenetic relationships of Roegneria, nuclear (ITS, Acc1, and Pgk1) and chloroplast (trnL–trnF) DNA regions were sequenced for 38 allopolyploid species and 32 diploid species of Triticeae. Phylogenetic analyses of nuclear DNA revealed that all Roegneria species were included in the St and Y genome clades, and that the Y genome was closely related to the V and Xp genomes. The chloroplast DNA dataset showed that Roegneria species were grouped with Pseudoroegneria species. The Pseudoroegneria species from the Middle East (P. libanotica and P. tauri) and Central Asia (P. strigosa) were more closely related to Roegneria species. The results suggested that: (i) the species containing the St and Y genomes should be segregated from Elymus and treated as a distinct genus, Roegneria, based on the genomic constitution; (ii) P. libanotica, P. tauri, and/or P. strigosa potentially served as the maternal donor of the St genome in Roegneria; (iii) The Y genome of Roegneria originated from a diploid Y genome species, and the V and Xp genomes may have contributed to Y genome formation; (iv) among Roegneria species of previously uncertain genomic constitution, R. seriotina was tetraploid and possessed the StY genomes, E. calcicolus was hexaploid with the StYH genomic constitution and should be classified in Campeiostachys, R. glaucifolia possessed the StStY genomes, and R. tschimganica had the genomic constitution St1St2Y. [ABSTRACT FROM AUTHOR]

Abstract: Roegneria C. Koch is a relatively large polyploid perennial genus with 130 species in the Triticeae, and consisting of the St and Y genomes. There are different opinions about whether Roegneria is an independent genus, or whether it should be included in the genus Elymus L. For many species of Roegneria, their genome constitution and phylogenetic relationship are still unknown. More research about the maternal genome donor of the Roegneria species is needed. To investigate the phylogenetic relationships and maternal genome donor of Roegneria and its affinitive genera, phylogenetic analyses of two chloroplast regions ndhF and trnH–psbA sequences were carried out in this study. The results showed that: (i) Campeiostachys Drobow (StYH) and all Roegneria (StY, StStY) species were scattered with Pseudoroegneria Á. Löve (St) species; (ii) R. sinica Keng, R. schugnanica (Nevski) Nevski, R. seriotina Keng, and Elymus calcicolus (Keng) Á. Löve containing the St genome; (iii) there was differentiation among species of Pseudoroegneria; and (iv) the St genome in diploid, tetraploid, and hexaploid species are divergent. Thus, it is suggested that: (i) Pseudoroegneria served as the maternal genome donor of Roegneria, including four species with unknown genomic constitutions (R. sinica, R. schugnanica, R. seriotina, and E. calcicolus); (ii) species of Roegneria or Pseudoroegneria might serve as the maternal genome donor of Campeiostachys; and (iii) the St genome has undergone differentiation during polyploidization in diploid, tetraploid, and hexaploid species. [ABSTRACT FROM AUTHOR]