Fluorescence in situ hybridization with probes for 45 cDNAs and five tandem repeats revealed homoeologous relationships of Agropyron cristatum with wheat. The results will contribute to alien gene introgression in wheat improvement. Crested wheatgrass (Agropyron cristatum L. Gaertn.) is a wild relative of wheat and a promising source of novel genes for wheat improvement. To date, identification of A. cristatum chromosomes has not been possible, and its molecular karyotype has not been available. Furthermore, homoeologous relationship between the genomes of A. cristatum and wheat has not been determined. To develop chromosome-specific landmarks, A. cristatum genomic DNA was sequenced, and new tandem repeats were discovered. Their distribution on mitotic chromosomes was studied by fluorescence in situ hybridization (FISH), which revealed specific patterns for five repeats in addition to 5S and 45S ribosomal DNA and rye subtelomeric repeats pSc119.2 and pSc200. FISH with one tandem repeat together with 45S rDNA enabled identification of all A. cristatum chromosomes. To analyze the structure and cross-species homoeology of A. cristatum chromosomes with wheat, probes for 45 mapped wheat cDNAs covering all seven chromosome groups were localized by FISH. Thirty-four cDNAs hybridized to homoeologous chromosomes of A. cristatum, nine hybridized to homoeologous and non-homoeologous chromosomes, and two hybridized to unique positions on non-homoeologous chromosomes. FISH using single-gene probes revealed that the wheat-A. cristatum collinearity was distorted, and important structural rearrangements were observed for chromosomes 2P, 4P, 5P, 6P and 7P. Chromosomal inversions were found for pericentric region of 4P and whole chromosome arm 6PL. Furthermore, reciprocal translocations between 2PS and 4PL were detected. These results provide new insights into the genome evolution within Triticeae and will facilitate the use of crested wheatgrass in alien gene introgression into wheat.

Field Crops Research Institute Agricultural Research Centre 9 Gamma Street Giza Cairo 12619 Egypt

Institute of Experimental Botany Center of the Region Haná for Biotechnological and Agricultural Research Šlechtitelů 31 78371 Olomouc Czech Republic

Wheat Genetics Resource Center Kansas State University 1712 Claflin Road 4024 Throckmorton PSC Manhattan KS 66506 USA

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Alkhimova AG, Heslop-Harrison JS, Shchapova AI, Vershinin AV. Rye chromosome variability in wheat-rye addition and substitution lines. Chromosome Res. 1999;7:205–212. doi: 10.1023/a:1009299300018. PubMed DOI

Altschul SF, Gish W, Miller W, et al. Basic local alignment search tool. J Mol Biol. 1990;215:403–410. doi: 10.1006/jmbi.1990.9999. PubMed DOI

Anathawat-Jonsson K, Heslop-Harrison JS. Isolation and characterization of genome-specific DNA-sequences in Triticeae species. Mol Gen Genet. 1993;240:151–158. doi: 10.1007/bf00277052. PubMed DOI

Appels R, Dennis ES, Smyth DR, Peacock WJ. 2 Repeated DNA-sequences from the heterochromatic regions of rye (Secale cereale) chromosomes. Chromosoma. 1981;84:265–277. doi: 10.1007/bf00399137. DOI

Asay KH, Jensen KB, Hsiao C, Dewey DR. Probable origin of standard crested wheatgrass, Agropyron desertorum Fisch ex Link, Schultes. Can J Plant Sci. 1992;72:763–772. doi: 10.4141/cjps92-092. DOI

Asghari A, Agayev Y, Fathi SAA. Karyological study of four species of wheat grass (Agropyron sp.) Pak J Biol Sci. 2007;10:1093–1097. doi: 10.3923/pjbs.2007.1093.1097. PubMed DOI

Badaeva ED, Friebe B, Gill BS. Genome differentiation in Aegilops. 1. Distribution of highly repetitive DNA sequences on chromosomes of diploid species. Genome. 1996;39:293–306. doi: 10.1139/g96-040. PubMed DOI

Badaeva ED, Amosova AV, Samatadze TE, et al. Genome differentiation in Aegilops. 4. Evolution of the U-genome cluster. Plant Syst Evol. 2004;246:45–76. doi: 10.1007/s00606-003-0072-4. DOI

Bedbrook JR, Jones J, Odell M, et al. Molecular description of telomeric heterochromatin in Secale species. Cell. 1980;19:545–560. doi: 10.1016/0092-8674(80)90529-2. PubMed DOI

Benavente E, Cifuentes M, Dusautoir JC, David J. The use of cytogenetic tools for studies in the crop-to-wild gene transfer scenario. Cytogenetic Genome Res. 2008;120:384–395. doi: 10.1159/000121087. PubMed DOI

Benson DA, Karsch-Mizrachi I, Lipman DJ, et al. GenBank. Nucleic Acids Res. 2010;38:D46–D51. doi: 10.1093/nar/gkp1024. PubMed DOI PMC

Brasileiro-Vidal AC, Cuadrado A, Brammer SP, et al. Chromosome characterization in Thinopyrum ponticum (Triticeae, Poaceae) using in situ hybridization with different DNA sequences. Genet Mol Biol. 2003;26:505–510. doi: 10.1590/s1415-47572003000400014. DOI

Brettell RIS, Banks PM, Cauderon Y, et al. A single wheatgrass chromosome reduces the concentration of barley yellow dwarf virus in wheat. Ann Appl Biol. 1988;113:599–603. doi: 10.1111/j.1744-7348.1988.tb03337.x. DOI

Busch W, Herrmann RG, Martin R. Refined physical mapping of the Sec-1 locus on the satellite of chromosome 1R of rye (Secale cereale) Genome. 1995;38:889–893. doi: 10.1139/g95-117. PubMed DOI

Cabrera A, Martin A, Barro F. In situ comparative mapping (ISCM) of Glu-1 loci in Triticum and Hordeum. Chromosome Res. 2002;10:49–54. doi: 10.1023/a:1014270227360. PubMed DOI

Castilho A, Heslop-Harrison JS. Physical mapping of 5S and 18S-25S rDNA and repetitive DNA-sequences in Aegilops umbellulata. Genome. 1995;38:91–96. doi: 10.1139/g95-011. PubMed DOI

Cauderon Y, Rhind JM. Effect on wheat of an Agropyron chromosome carrying stripe rust resistance. Ann De L Amelior Des Plantes. 1976;26:745–749.

Chen Q, Jahier J, Cauderon Y. Production and cytogenetical studies of hybrids between Triticum aestivum and Agropyron cristatum Gaertn. Comptes Rendus De L Academie Des Sciences Serie Iii-Sciences De La Vie-Life Sciences. 1989;308:425–430.

Contento A, Heslop-Harrison JS, Schwarzacher T. Diversity of a major repetitive DNA sequence in diploid and polyploid Triticeae. Cytogenet Genome Res. 2005;109:34–42. doi: 10.1159/000082379. PubMed DOI

Danilova TV, Friebe B, Gill BS. Single-copy gene fluorescence in situ hybridization and genome analysis: Acc-2 loci mark evolutionary chromosomal rearrangements in wheat. Chromosoma. 2012;121:597–611. doi: 10.1007/s00412-012-0384-7. PubMed DOI

Danilova TV, Friebe B, Gill BS. Development of a wheat single gene FISH map for analyzing homoeologous relationship and chromosomal rearrangements within the Triticeae. Theor Appl Genet. 2014;127:715–730. doi: 10.1007/s00122-013-2253-z. PubMed DOI PMC

Danilova TV, Akhunova AR, Akhunov ED, et al. Major structural genomic alterations can be associated with hybrid speciation in Aegilops markgrafii (Triticeae) Plant J. 2017;92:317–330. doi: 10.1111/tpj.13657. PubMed DOI

De Carvalho R, Guerra M. Cytogenetics of Manihot esculenta Crantz (cassava) and eight related species. Hereditas. 2002;136:159–168. doi: 10.1034/j.1601-5223.2002.1360212.x. PubMed DOI

Del Fabbro C, Scalabrin S, Morgante M, Giorgi FM. An extensive evaluation of read trimming effects on Illumina NGS data analysis. PLoS ONE. 2013 doi: 10.1371/journal.pone.0085024. PubMed DOI PMC

Devos KM, Gale MD. Genome relationships: the grass model in current research. Plant Cell. 2000;12:637–646. doi: 10.1105/tpc.12.5.637. PubMed DOI PMC

Devos KM, Atkinson MD, Chinoy CN, et al. Chromosomal rearrangements in the rye genome relative to that of wheat. Theor Appl Genet. 1993;85:673–680. doi: 10.1007/bf00225004. PubMed DOI

Devos KM, Dubcovsky J, Dvorak J, et al. Structural evolution of wheat chromosomes 4A, 5A, and 7B and its impact on recombination. Theor Appl Genet. 1995;91:282–288. doi: 10.1007/bf00220890. PubMed DOI

Dewey DR. Historical and current taxonomic perspectives of Agropyron, Elymus, and related genera. Crop Sci. 1983;23:637–642. doi: 10.2135/cropsci1983.0011183X002300040009x. DOI

Dewey DR, Asay KH. Cytogenetic and taxonomic relationships among three diploid crested wheat grasses. Crop Sci. 1982;22:645–650. doi: 10.2135/cropsci1982.0011183X002200030052x. DOI

Doležel J, Bartoš J, Voglmayr H, Greilhuber J. Nuclear DNA content and genome size of trout and human. Cytometry. 2003;51:127–128. doi: 10.1002/cyto.a.10013. PubMed DOI

Doležel J, Greilhuber J, Suda J. Estimation of nuclear DNA content in plants using flow cytometry. Nat Protoc. 2007;2:2233–2244. doi: 10.1038/nprot.2007.310. PubMed DOI

Dvořák J, Zhang HB, Kota RS, Lassner M. Organization and evolution of the 5S-ribosomal RNA gene family in wheat and related species. Genome. 1989;32:1003–1016. doi: 10.1139/g89-545. DOI

Feuillet C, Langridge P, Waugh R. Cereal breeding takes a walk on the wild side. Trends Genet. 2008;24:24–32. doi: 10.1016/j.tig.2007.11.001. PubMed DOI

Friebe B, Mukai Y, Dhaliwal HS, et al. Identification of alien chromatin specifying resistance to wheat streak mosaic and greenbug in wheat germ plasm by C-banding and in situ hybridization. Theor Appl Genet. 1991;81:381–389. PubMed

Friebe B, Jiang J, Raupp WJ, et al. Characterization of wheat-alien translocations conferring resistance to diseases and pests: current status. Euphytica. 1996;91:59–87. doi: 10.1007/bf00035277. DOI

Fu S, Lv Z, Guo X, et al. Alteration of terminal heterochromatin and chromosome rearrangements in derivatives of wheat-rye hybrids. J Genet Genom. 2013;40:413–420. doi: 10.1016/j.jgg.2013.05.005. PubMed DOI

Fu S, Chen L, Wang Y, et al. Oligonucleotide probes for ND-FISH analysis to identify rye and wheat chromosomes. Sci Rep. 2015;5:10552. doi: 10.1038/srep10552. PubMed DOI PMC

Fukui K, Kamisugi Y, Sakai F. Physical mapping of 5S rDNA loci by direct-cloned biotinylated probes in barley chromosomes. Genome. 1994;37:105–111. doi: 10.1139/g94-013. PubMed DOI

Gale MD, Devos KM. Plant comparative genetics after 10 years. Science. 1998;282:656–659. doi: 10.1126/science.282.5389.656. PubMed DOI

Gerlach WL, Bedbrook JR. Cloning and characterization of ribosomal-RNA genes from wheat and barley. Nucleic Acids Res. 1979;7:1869–1885. doi: 10.1093/nar/7.7.1869. PubMed DOI PMC

Gill BS, Friebe B, Endo TR. Standard karyotype and nomenclature system for description of chromosome bands and structural-aberrations in wheat (Triticum aestivum) Genome. 1991;34:830–839. doi: 10.1139/g91-128. DOI

Gill BS, Friebe B, Raupp WJ, et al. Wheat Genetics Resource Center: the first 25 years. Adv Agron. 2006;89:73–136. doi: 10.1016/s0065-2113(05)89002-9. DOI

Guerra M, Kenton A, Bennett MD. rDNA sites in mitotic and polytene chromosomes of Vigna unguiculata (L) Walp and Phaseolus coccineus L revealed by in situ hybridization. Ann Bot. 1996;78:157–161. doi: 10.1006/anbo.1996.0108. DOI

Han FP, Fedak G, Guo WL, Liu B. Rapid and repeatable elimination of a parental genome-specific DNA repeat (pGcIR-1a) in newly synthesized wheat allopolyploids. Genetics. 2005;170:1239–1245. doi: 10.1534/genetics.104.039263. PubMed DOI PMC

Han H, Bai L, Su J, et al. Genetic rearrangements of six wheat-Agropyron cristatum 6P addition lines revealed by molecular markers. PLoS ONE. 2014 doi: 10.1371/journal.pone.0091066. PubMed DOI PMC

Han H, Liu W, Lu Y, et al. Isolation and application of P genome-specific DNA sequences of Agropyron Gaertn. in Triticeae. Planta. 2017;245:425–437. doi: 10.1007/s00425-016-2616-1. PubMed DOI

He Q, Cai Z, Hu T, et al. Repetitive sequence analysis and karyotyping reveals centromere-associated DNA sequences in radish (Raphanus sativus L.) BMC Plant Biol. 2015 doi: 10.1186/s12870-015-0480-y. PubMed DOI PMC

Hsiao C, Wang RRC, Dewey DR. Karyotype analysis and genome relationships of 22 diploid species in the tribe Triticeae. Can J Genet Cytol. 1986;28:109–120. doi: 10.1139/g86-015. DOI

Hsiao C, Asay KH, Dewey DR. Cytogenetic analysis of interspecific hybrids and amphiploids between 2 diploid crested wheatgrasses, Agropyron mongolicum and A. cristatum. Genome. 1989;32:1079–1084. doi: 10.1139/g89-557. DOI

Hu L-J, Liu C, Zeng Z-X, et al. Genomic rearrangement between wheat and Thinopyrum elongatum revealed by mapped functional molecular markers. Genes Genom. 2012;34:67–75. doi: 10.1007/s13258-011-0153-7. DOI

Jabeen R, Iftikhar T, Mengal T, Khattak MI. A comparative chromosomal count and morphological karyotyping of three indigenous cultivars of kalongi (Nigella sativa L.) Pak J Bot. 2012;44:1007–1012.

Jiang J, Gill BS, Wang GL, et al. Metaphase and interphase fluorescence in situ hybridization mapping of the rice genome with bacterial artificial chromosomes. Proc Natl Acad Sci USA. 1995;92:4487–4491. doi: 10.1073/pnas.92.10.4487. PubMed DOI PMC

Jubault M, Tanguy AM, Abelard P, et al. Attempts to induce homoeologous pairing between wheat and Agropyron cristatum genomes. Genome. 2006;49:190–193. doi: 10.1139/g05-074. PubMed DOI

Karafiátová M, Bartoš J, Kopecký D, et al. Mapping nonrecombining regions in barley using multicolor FISH. Chrom Res. 2013;21:739–751. doi: 10.1007/s10577-013-9380-x. PubMed DOI

Kato A, Lamb JC, Birchler JA. Chromosome painting using repetitive DNA sequences as probes for somatic chromosome identification in maize. Proc Natl Acad Sci USA. 2004;101:13554–13559. doi: 10.1073/pnas.0403659101. PubMed DOI PMC

Kato A, Albert PS, Vega JM, Birchler JA. Sensitive fluorescence in situ hybridization signal detection in maize using directly labeled probes produced by high concentration DNA polymerase nick translation. Biotech Histochem. 2006;81:71–78. doi: 10.1080/10520290600643677. PubMed DOI

Kawaura K, Mochida K, Enju A, et al. Assessment of adaptive evolution between wheat and rice as deduced from full-length common wheat cDNA sequence data and expression patterns. BMC Genom. 2009 doi: 10.1186/1471-2164-10-271. PubMed DOI PMC

Kharb P, Dong JJ, Islam-Faridi MN, et al. Fluorescence in situ hybridization of single copy transgenes in rice chromosomes. In Vitro Cellular Dev Biol Plant. 2001;37:1–5. doi: 10.1007/s11627-001-0001-6. DOI

Kim JS, Islam-Faridi MN, Klein PE, et al. Comprehensive molecular cytogenetic analysis of Sorghum genome architecture distribution of euchromatin heterochromatin, genes and recombination in comparison to rice. Genetics. 2005;171:1963–1976. doi: 10.1534/genetics.105.048215. PubMed DOI PMC

Kishii M, Yamada T, Sasakuma T, Tsujimoto H. Production of wheat-Leymus racemosus chromosome addition lines. Theor Appl Genet. 2004;109:255–260. doi: 10.1007/s00122-004-1631-y. PubMed DOI

Knott DR. Effect on wheat of Agropyron chromosome carrying rust resistance. Can J Genet Cytol. 1964;6:500–507. doi: 10.1139/g64-064. PubMed DOI

Knott DR. Translocations involving Triticum chromosomes and Agropyron chromosomes carrying rust resistance. Can J Genet Cytol. 1968;10:695–696. doi: 10.1139/g68-087. PubMed DOI

Li L, Yang X, Zhou R, et al. Establishment of wheat-Agropyron cristatum alien addition lines: II. Identification of alien chromosomes and analysis of development approaches. Acta Genet Sin. 1998;25:538–544.

Li G-R, Liu C, Wei P, et al. Chromosomal distribution of a new centromeric Ty3-gypsy retrotransposon sequence in Dasypyrum and related Triticeae species. J Genet. 2012;91:343–348. doi: 10.1007/s12041-012-0181-3. PubMed DOI

Li Q, Lu Y, Pan C, et al. Characterization of a novel wheat-Agropyron cristatum 2P disomic addition line with powdery mildew resistance. Crop Sci. 2016;56:2390–2400. doi: 10.2135/cropsci2015.10.0638. DOI

Li D, Li T, Wu Y, et al. FISH-Based markers enable identification of chromosomes derived from tetraploid Thinopyrum elongatum in hybrid lines. Front Plant Sci. 2018;9:526. doi: 10.3389/fpls.2018.00526. PubMed DOI PMC

Limin AE, Fowler DB. An interspecific hybrid and amphiploid produced from Triticum aestivum crosses with Agropyron cristatum and Agropyron desertorum. Genome. 1990;33:581–584. doi: 10.1139/g90-085. DOI

Linc G, Gaal E, Molnar I, et al. Molecular cytogenetic (FISH) and genome analysis of diploid wheatgrasses and their phylogenetic relationship. PLoS ONE. 2017 doi: 10.1371/journal.pone.0173623. PubMed DOI PMC

Liu W, Liu W, Wu J, et al. Analysis of genetic diversity in natural populations of Psathyrostachys huashanica Keng using microsatellite (SSR) markers. Agric Sci China. 2010;9:463–471. doi: 10.1016/s1671-2927(09)60118-8. DOI

Luan Y, Wang X, Liu W, et al. Production and identification of wheat-Agropyron cristatum 6P translocation lines. Planta. 2010;232:501–510. doi: 10.1007/s00425-010-1187-9. PubMed DOI

Martin A, Cabrera A, Esteban E, et al. A fertile amphiploid between diploid wheat (Triticum tauschii) and crested wheatgrass (Agropyron cristatum) Genome. 1999;42:519–524. doi: 10.1139/gen-42-3-519. PubMed DOI

McArthur RI, Zhu XW, Oliver RE, et al. Homoeology of Thinopyrum junceum and Elymus rectisetus chromosomes to wheat and disease resistance conferred by the Thinopyrum and Elymus chromosomes in wheat. Chrom Res. 2012;20:699–715. doi: 10.1007/s10577-012-9307-y. PubMed DOI

McGuire PE, Dvorak J. High salt tolerance potential in wheatgrasses. Crop Sci. 1981;21:702–705. doi: 10.2135/cropsci1981.0011183X002100050018x. DOI

Mickelsonyoung L, Endo TR, Gill BS. A cytogenetic ladder-map of the wheat homoeologous group-4 chromosomes. Theor Appl Genet. 1995;90:1007–1011. PubMed

Miftahudin Ross K, Ma XF, et al. Analysis of expressed sequence tag loci on wheat chromosome group 4. Genetics. 2004;168:651–663. doi: 10.1534/genetics.104.034827. PubMed DOI PMC

Mirzaghaderi G, Houben A, Badaeva ED. Molecular-cytogenetic analysis of Aegilops triuncialis and identification of its chromosomes in the background of wheat. Mol Cytogenet. 2014 doi: 10.1186/s13039-014-0091-6. PubMed DOI PMC

Mukai Y, Endo TR, Gill BS. Physical mapping of the 5S ribosomal-RNA multigene family in common wheat. J Hered. 1990;81:290–295. doi: 10.1093/oxfordjournals.jhered.a110991. DOI

Mukai Y, Endo TR, Gill BS. Physical mapping of the 18S.26S ribosomal-RNA multigene family in common wheat: identification of a new locus. Chromosoma. 1991;100:71–78. doi: 10.1007/bf00418239. DOI

Nagaki K, Tsujimoto H, Isono K, Sasakuma T. Molecular characterization of a tandem repeat, AFA family, and distribution among Triticeae. Genome. 1995;38:479–486. doi: 10.1139/g95-063. PubMed DOI

Naranjo CA, Poggio L, Brandham PE. A practical method of chromosome classification on the basis of centromere position. Genetica. 1983;62:51–53. doi: 10.1007/BF00123310. DOI

Naranjo T, Roca A, Goicoechea PG, Giraldez R. Arm homoeology of wheat and rye chromosomes. Genome. 1987;29:873–882. doi: 10.1139/g87-149. DOI

Nasuda S, Friebe B, Gill BS. Gametocidal genes induce chromosome breakage in the interphase prior to the first mitotic cell division of the male gametophyte in wheat. Genetics. 1998;149:1115–1124. PubMed PMC

Novák P, Neumann P, Macas J. Graph-based clustering and characterization of repetitive sequences in next-generation sequencing data. BMC Bioinform. 2010 doi: 10.1186/1471-2105-11-378. PubMed DOI PMC

Novák P, Neumann P, Pech J, et al. RepeatExplorer: a Galaxy-based web server for genome-wide characterization of eukaryotic repetitive elements from next-generation sequence reads. Bioinformatics. 2013;29:792–793. doi: 10.1093/bioinformatics/btt054. PubMed DOI

Ochoa V, Madrid E, Said M, et al. Molecular and cytogenetic characterization of a common wheat-Agropyron cristatum chromosome translocation conferring resistance to leaf rust. Euphytica. 2015;201:89–95. doi: 10.1007/s10681-014-1190-5. DOI

Paterson AH, Bowers JE, Burow M, et al. Comparative genomics of plant chromosomes. Plant Cell. 2000;12:1523–1539. doi: 10.1105/tpc.12.9.1523. PubMed DOI PMC

Qi L, Friebe B, Zhang P, Gill BS. Homoeologous recombination, chromosome engineering and crop improvement. Chrom Res. 2007;15:3–19. doi: 10.1007/s10577-006-1108-8. PubMed DOI

Reddy P, Appels R. A 2nd locus for the 5S multigene family in Secale L.: sequence divergence in 2 lineages of the family. Genome. 1989;32:456–467. doi: 10.1139/g89-469. PubMed DOI

Said M, Cabrera A. A physical map of chromosome 4Hch from H. chilense containing SSR, STS and EST-SSR molecular markers. Euphytica. 2009;167:253–259. doi: 10.1007/s10681-009-9895-6. DOI

Said M, Recio R, Cabrera A. Development and characterisation of structural changes in chromosome 3 Hch from Hordeum chilense in common wheat and their use in physical mapping. Euphytica. 2012;188:429–440. doi: 10.1007/s10681-012-0712-2. DOI

Sato S, Hizume M, Kawamura S. Relationship between secondary constrictions and nucleolus organizing regions in Allium sativum chromosomes. Protoplasma. 1980;105:77–85. doi: 10.1007/bf01279851. DOI

Schneider A, Linc G, Molnar-Lang M. Fluorescence in situ hybridization polymorphism using two repetitive DNA clones in different cultivars of wheat. Plant Breed. 2003;122:396–400. doi: 10.1046/j.1439-0523.2003.00891.x. DOI

Schneider A, Linc G, Molnar I, Molnar-Lang M. Molecular cytogenetic characterization of Aegilops biuncialis and its use for the identification of 5 derived wheat-Aegilops biuncialis disomic addition lines. Genome. 2005;48:1070–1082. doi: 10.1139/g05-062. PubMed DOI

Schulz-Schaeffer J, Allderdice PW, Creel GC. Segmental allo-polyploidy in tetraploid and hexaploid Agropyron species of the crested wheatgrass complex (Section Agropyron) Crop Sci. 1963;3:525–530. doi: 10.2135/cropsci1963.0011183X000300060021x. DOI

Sharma HC, Gill BS, Uyemoto JK. High levels of resistance in Agropyron species to barley yellow dwarf and wheat streak mosaic viruses. Phytopathol Z J Phytopathol. 1984;110:143–147. doi: 10.1111/j.1439-0434.1984.tb03402.x. DOI

Shukle RH, Lampe DJ, Lister RM, Foster JE. Aphid feeding behavior: relationship to barley yellow dwarf virus-resistance in Agropyron species. Phytopathology. 1987;77:725–729. doi: 10.1094/Phyto-77-725. DOI

Smit S, Widmann J, Knight R. Evolutionary rates vary among rRNA structural elements. Nucl Acids Res. 2007;35:3339–3354. doi: 10.1093/nar/gkm101. PubMed DOI PMC

Song L, Jiang L, Han H, et al. Efficient induction of wheat-Agropyron cristatum 6P translocation lines and GISH detection. PLoS ONE. 2013 doi: 10.1371/journal.pone.0069501. PubMed DOI PMC

Song L, Lu Y, Zhang J, et al. Physical mapping of Agropyron cristatum chromosome 6P using deletion lines in common wheat background. Theor Appl Genet. 2016;129:1023–1034. doi: 10.1007/s00122-016-2680-8. PubMed DOI

Sonnhammer ELL, Durbin R. A dot-matrix program with dynamic threshold control suited for genomic DNA and protein sequence analysis. Gene-Combis. 1995;167:1–10. doi: 10.1016/0378-1119(95)00657-5. PubMed DOI

Sousa A, Barros e Silva AE, Cuadrado A, et al. Distribution of 5S and 45S rDNA sites in plants with holokinetic chromosomes and the “chromosome field” hypothesis. Micron. 2011;42:625–631. doi: 10.1016/j.micron.2011.03.002. PubMed DOI

Stebbins GL. Types of polyploids: their classification and significance. Adv Genet Incorporating Mol Genet Med. 1947;1:403–429. doi: 10.1016/s0065-2660(08)60490-3. PubMed DOI

Svitashev S, Bryngelsson T, Li XM, Wang RRC. Genome-specific repetitive DNA and RAPD markers for genome identification in Elymus and Hordelymus. Genome. 1998;41:120–128. doi: 10.1139/gen-41-1-120. PubMed DOI

Szakács É, Molnár-Láng M. Fluorescent in situ hybridization polymorphism on the 1RS chromosome arms of cultivated Secale cereale species. Cereal Res Commun. 2008;36:247–255. doi: 10.1556/CRC.36.2008.2.5. DOI

Tang Z-X, Fu S-L, Ren Z-L, et al. Variations of tandem repeat, regulatory element, and promoter regions revealed by wheat-rye amphiploids. Genome. 2008;51:399–408. doi: 10.1139/g08-027. PubMed DOI

Tang Z, Yang Z, Fu S. Oligonucleotides replacing the roles of repetitive sequences pAs1, pSc119.2, pTa-535, pTa71, CCS1, and pAWRC.1 for FISH analysis. J Appl Genet. 2014;55:313–318. doi: 10.1007/s13353-014-0215-z. PubMed DOI

Tang S, Qiu L, Xiao Z, et al. New oligonucleotide probes for ND-FISH analysis to identify barley chromosomes and to investigate polymorphisms of wheat chromosomes. Genes. 2016;7:118. doi: 10.3390/genes7120118. PubMed DOI PMC

Untergasser A, Cutcutache I, Koressaar T, et al. Primer3-new capabilities and interfaces. Nucl Acids Res. 2012;40:e115. doi: 10.1093/nar/gks596. PubMed DOI PMC

Vershinin AV, Schwarzacher T, Heslop-Harrison JS. The large-scale genomic organization of repetitive dna families at the telomeres of rye chromosomes. Plant Cell. 1995;7:1823–1833. PubMed PMC

Wang RRC. Agropyron and Psathyrostachys. Wild Crop Relat Genom Breed Res Cereals. 2011 doi: 10.1007/978-3-642-14228-4_2. DOI

Wang CJR, Harper L, Cande WZ. High-resolution single-copy gene fluorescence in situ hybridization and its use in the construction of a cytogenetic map of maize chromosome 9. Plant Cell. 2006;18:529–544. doi: 10.1105/tpc.105.037838. PubMed DOI PMC

Wang Q, Xiang J, Gao A, et al. Analysis of chromosomal structural polymorphisms in the St, P, and Y genomes of Triticeae (Poaceae) Genome. 2010;53:241–249. doi: 10.1139/g09-098. PubMed DOI

Wu J, Yang X, Wang H, et al. The introgression of chromosome 6P specifying for increased numbers of florets and kernels from Agropyron cristatum into wheat. Theor Appl Genet. 2006;114:13–20. doi: 10.1007/s00122-006-0405-0. PubMed DOI

Wu M, Zhang JP, Wang JC, et al. Cloning and characterization of repetitive sequences and development of SCAR markers specific for the P genome of Agropyron cristatum. Euphytica. 2010;172:363–372. doi: 10.1007/s10681-009-0033-2. DOI

Yang C-T, Fan X, Wang X-L, et al. Karyotype analysis of Agropyron cristatum (L.) Gaertner. Caryologia. 2014;67:234–237. doi: 10.1080/0144235x.2014.974351. DOI

Ye X, Lu Y, Liu W, et al. The effects of chromosome 6P on fertile tiller number of wheat as revealed in wheat-Agropyron cristatum chromosome 5A/6P translocation lines. Theor Appl Genet. 2015;128:797–811. doi: 10.1007/s00122-015-2466-4. PubMed DOI

Zhang H, Jia J, Gale MD, Devos KM. Relationships between the chromosomes of Aegilops umbellulata and wheat. Theor Appl Genet. 1998;96:69–75. doi: 10.1007/s001220050710. DOI

Zhang P, Li WL, Fellers J, et al. BAC-FISH in wheat identifies chromosome landmarks consisting of different types of transposable elements. Chromosoma. 2004;112:288–299. doi: 10.1007/s00412-004-0273-9. PubMed DOI

Zhang H, Bian Y, Gou X, et al. Intrinsic karyotype stability and gene copy number variations may have laid the foundation for tetraploid wheat formation. Proc Natl Acad Sci USA. 2013;110:19466–19471. doi: 10.1073/pnas.1319598110. PubMed DOI PMC

Zhang J, Liu W, Han H, et al. De novo transcriptome sequencing of Agropyron cristatum to identify available gene resources for the enhancement of wheat. Genomics. 2015;106:129–136. doi: 10.1016/j.ygeno.2015.04.003. PubMed DOI

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