Genome Analysis of South American Elymus (Triticeae) and Leymus (Triticeae) Species Based on Variation in Repeated Nucleotide Sequences
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UC Davis UC Davis Previously Published Works Title Genome analysis of South American Elymus (Triticeae) and Leymus (Triticeae) species based on variation in repeated nucleotide sequences. Permalink https://escholarship.org/uc/item/54w48156 Journal Genome, 40(4) ISSN 0831-2796 Authors Dubcovsky, J Schlatter, AR Echaide, M Publication Date 1997-08-01 DOI 10.1139/g97-067 Peer reviewed eScholarship.org Powered by the California Digital Library University of California Genome analysis of South American Elymus (Triticeae) and Leymus (Triticeae) species based on variation in repeated nucleotide sequences Jorge DU~COVS~~,A.R. Schlatter, and M. Echaide Abstract: Variation in repeated nucleotide sequences (RNSs) at the level of entire families assayed by Southern blot hybridization is remarkably low within species and is a powerful tool for scrutinizing the origin of allopolyploid taxa. Thirty-one clones from RNSs isolated from different Triticeae genera were used to investigate the genome constitution of South American Elymus. One of these clones, pHch2, preferentially hybridized with the diploid H genome Hordeum species. Hybridization of this clone with a worldwide collection of Elymus species with known genome formulas showed that pHch2 clearly discriminates Elymus species with the H genome (StH, StHH, StStH, and StHY) from those with other genome combinations (Sty, StStY, StPY, and StP). Hybridization with pHch2 indicates the presence of the H genome in all South American Elymus species except Elymus erianthus and Elymus mendocinus. Hybridization with additional clones that revealed differential restriction fragments (marker bands) for the H genome confirmed the absence of the H genome in these species. Differential restriction fragments for the NS genome of Psathyrostachys were detected in E. erianthus and E. mendocinus and three species of Leymus. Based on genome constitution, morphology, and habitat, E. erianthus and E. mendocinus were transferred to the genus Leymus. Key words: Triticeae, Elymus, Leymus, repeated sequences. Resume : La variation des stquences nucltotidiques rtptttes (RNS) prtsente au niveau de familles botaniques enti&res,telle que rtvtlte par hybridation Southern, est ttonnamment faible entre esp2ces et constitue un outil puissant pour analyser l'origine de taxons allopolyploides. Trente et un clones RNS isolts chez difftrents genres appartenant aux Triticeae ont ttt employts pour analyser la composition gtnomique des esp2ces du genre Elymus en Amtrique du Sud. Un de ces clones, pHch2, montre une hybridation prtftrentielle avec les esp2ces du genre Hordeum h gtnome H diploides. L'emploi de ce clone comme sonde lors For personal use only. d'hybridations avec une collection internationale d'esp2ces d'Elymus ayant une composition gtnomique connue a montrt que pHch2 permet de distinguer nettement les tlymes portant le gtnome H (StH, StHH, StStH et StHY) des tlymes ne posstdant pas un tel gtnome (Sty, StStY, StPY et StP). L'hybridation avec la sonde pHch2 a montrt la presence du gtnome H chez toutes les esp2ces sud-amtricaines h l'exception du Elymus erianthus et du Elymus mendocinus. Des hybridations additionnelles avec des clones qui rtv2lent des bandes sptcifiques au gtnome H ont confirm6 l'absence de ce gtnome parmi ces esp2ces. Des fragments de restriction sptcifiques au gtnome NS du Psathyrostachys ont ttt dttectts chez les esp2ces E. erianthus et E. mendocinus de meme que chez trois esp2ces du genre Leymus. En se fondant sur leur composition gtnomique, leur morphologie et leur habitat, les esp2ces E. erianthus et E. mendocinus sont considtrtes comme faisant partie du genre Leymus. Mots clbs : Triticeae, Elymus, Leymus, stquences rtptttes. [Traduit par la Redaction] times as many as the second largest genus, Hordeum L. Genome Downloaded from www.nrcresearchpress.com by Calif Dig Lib - Davis on 03/28/17 Introduction (approximately 40 species). Species of Elymus are allopoly- The genus Elymus L. is the largest among the perennial ploids cytologically characterized by genome combinations of Triticeae. It contains approximately 150 species, almost four five basic genomes: S' from Pseudoroegneria (Nevski) A. Love, H from Hordeum L., Y from an unknown diploid spe- Corresponding Editor: G. Fedak. cies, P fror? Agropyron Gaertn., and W from Austmlopyrum Received January 3, 1996. Accepted April 14, 1997. (Tzvelev) A. Love (Dewey 1984; Love 1984; Jensen 1989; Jensen 1990a, 1990b, 1990~;Lu 1993). Genome symbols are J. ~ubcovsk~.'Department of Agronomy and Range Science, University of California, Davis, CA 95616, U.S.A. in accordance with the system proposed at the 2nd Interna- tional Triticeae Symposium (Wang et al. 1994). A.R. Schlatter and M. Echaide. Instituto de Recursos Biol6gicos. Elymus species with different genome combinations differ Centro de Investigaciones en Recursos Naturates (CIRN), Instituto in their geographic distribution. The basic genome W has been Nacional de Tecnologia Agropecuaria (INTA), Villa Udaondo, 17 12 Castelar, Buenos Aires, Argentina. identified only in one Australasian hexaploid (S'YW; Torabinejad and Mueller 1993) and the basic genome P is ' Author to whom all correspondence should be addressed restricted to some Central Asiatic hexaploids (S'PY; Jensen (e-mail: [email protected]). Genome, 40: 505-520 (1997) 01997 NRC Canada Genome, Vol. 40, 1997 1990b, 1990~).The Y genome has a wider distribution and is NSgenome specific repeated nucleotide sequences and H and found in many Asiatic tetraploids and hexaploids (s'Y, S'S'Y, NS genome specific restriction fragments of repeated se- S'HY, and S'PY; Lu 1993). Finally, species with St-H quences (marker bands). We also investigate the use of these genome combinations (S'H, S'S'H, S'HH, and S'S'HH) have repetitive sequences as a tool for genome analysis in Elymus the widest geographic distribution, being found in Europe, by using a worldwide set of species with known genome con- Asia, North America, South America, Australia, and New stitutions. Zealand (Dewey 1984; Love 1984). Genome formulas are known only for a small number of Materials and methods South American Elymus species. Genome analysis has resulted in the tetraploid species Elymus agropyroides Plant materials Presl, Elymus tilcarensis (Hunziker) A. Love, and Elymus The species analyzed, together with their genome constitution, acces- magellanicus (Desv.) A. Love being assigned the genome sion number, and origin, are listed in Table 1. Voucher specimens of formula S'H (Dewey 1970b, 1977; Jensen 1993) and the the South American Elymus species are deposited in the herbarium of the Instituto de Recursos Biologicas (IRB), Instituto Nacional de hexaploid species Elymus patagonicus Speg. and Elymus Tecnologia Agropecuaria (INTA) (BAB, Castelar, Buenos Aires, scabriglumis (Hakel) A. Love being assigned the genome for- Argentina). Herbarium acronyms are according to Holmgren et al. mula S'HH (Hunziker 1953, 1966; Dewey 1972c; Seberg (Holmgren et al. 1990). Seeds of the Elymus species from North 1991). Gupta et. a1 (1988) suggested that the Y genome was America, Europe, and Asia were provided by Dr. R.C. Johnson of the present in E. scabriglumis, but later concluded that the genome United States Department of Agriculture, Agricultural Research formula of this species was S'HH (Lee et al. 1994). In spite of Service, Western Regional Plant Introduction Station, Pullman, this apparent genome uniformity, poor chromosome pairing in Wash., U.S.A. Seeds of the Hordeum species were provided by Dr. R. meiosis of interspecific hybrids has revealed the presence of von Bothmer of the Swedish University of Agricultural Sciences, genome differentiation among some tetraploid South Ameri- Svalov, Sweden. can Elymus species (Hunziker et al. 1965; Hunziker and South American Elymus species were identified using the keys of Nicora (1978) and Hunziker (1966). Elymus angulatus Presl did not Ferrari 1986). flower and it was not possible to verify the identification provided by Karyotype analysis of the South American Elymus species the collector, Dr. 0. Seberg (University of Copenhagen, Denmark). suggested that the S'H genome was present in all South Delimitation of the genus Elymus followed Love (Love 1984; American tetraploids analyzed, but indicated differential char- Zuloaga et al. 1994), and Hordeum was considered in sensu Bothmer acteristics in the karyotypes of the hexaploid Elymus erianthus (Bothmer et al. 1991). When all the South American species of Philippi and the octoploid Elymus mendocinus (Parodi) Agropyron were transferred to Elymus (Love 1984), Agropyron A. Love (Dubcovsky et al. 1989; Lewis et al. 1996). C-banding scabrifolium (Doll) Parodi wa: included as a subspecies of Elymus and N-banding of E. erianthus chromosomes (Seberg and breviaristatus (A.S. Hitchc.) A. Love. This is probably incorrect, Linde-Laursen 1996) and hybridization with a GAA satellite because A. scabrifolium and Agropyron breviaristatum A.S. Hitchc. (Pedersen et al. 1996) and four repetitive DNA sequences are reproductively isolated species (Hunzik~ret al. 1965). Since E. breviaristatus ssp. scabrifolious (Doll) A. Love (Love 1984; For personal use only. cloned from barley (Svitashev et al. 1996) revealed additional Zuloaga et al. 1994) is the only published name for this taxon under differences and suggested the absence of the St and H genomes Elymus, we temporarily use it for the sake of consistency. A taxo- from this species (Seberg and Linde-Laursen 1996). nomic review of this species is in preparation (0. Seberg,