Variation Of The StH Genome In Triticeae And Geonme Constitution Of Elymus Tangutorum Using The Genomic In Situ Hybridization

At present, Triticeae species with the StH genome are about20species in the world. They are mainly distributing in the temperate and warm temperate regions in the word, ranging from Eurasia to North America. They are growing in grassland, valley, forest, grassland edge environment. Most of the species, such as the Elymus sibiricus L., Elymus canadensis L., Elytrigia repens (L.) Nevski, etc., are important economic value of forage and widely planted in northern China, the western highlands, as well as foreign pastures.Although having the same StH genomes, species with the StH genomes show different morphological characters. Some of the characters, such as glume, lemma, the number of spikelet in per node of each ear, are used as an important classification index. Morphologically, classified from the number of spikelet in per node of each ear, some species are single spikelet in per node (such as Elymus caninus, Elymus lanceolatus, Elytrigia repens), some species are double spikelets in per node (such as Elymus. sibiricus, Hystrix patula, Sitanion hystrix) and some species show three or four spikelets in per node (such as Elymus canadensis). Because of the huge morphological differences, these species with StH genome had been attributed to different genera and as the mode species of the genus. For example, Elymus sibiricus was the type species of the Elymus genus, Sitanion hystrix was the type species of the Sitanion genus, Hystrix patula was the type of the Hystrix genus and Elytrigia repens was the type species of the Elytrigia genus. In the present study, we use the technique of genomic in situ hybridization (GISH), to analyse the StH genome of Triticeae with different geographical distribution and morphological characteristics, and to explore the variation and differentiation of StH genome in Triticeae.Elymus tangutorum (Nevski) Hand.-Mazz. is the hexaploid species of Elymus. Some scholars classified it to the Elymus dahuricus complex, while some other one transferred it to the new genus Campeiostachys Drobov.. At present, the genome composition of the E. tangutorum is still unknown. Some one reported that E. tangutorum contained the StYH genome, while some one suggested that it has the StHH genome. In order to explore the variation and differentiation of StH genome in Triticeae and the genome constitution of Elymus tangutorum, we using the genomic in situ hybridization (GISH) to study the the variation of the StH genome and genome constitution of Elymus tangutorum. The main results as follows:1. In E. canadensis, E. wawawaiensis, E. caninus, E. multisetus, E. elymoides ssp. brevifolius, and E. elymoides ssp. elymoides,14chromosomes show yellow fluorescence hybridization signals when probing with H-genome DNA of H. chilense and blocking with St-genome DNA of P. strigosa ssp. aegilopoides. The result indicates that these six species contain the H genome from Hordeum. In E. caninus、E. multisetus、E. virgensis,14chromosomes show yellow fluorescence signals when probing with St-genome DNA of P. strigosa ssp. aegilopoides and blocking with H-genome DNA of H. chilense. The result indicates that these three species contain the St genome from Pseudoroegneria.2. Six species with the StH genome showed different fluorescence hybridization when probing with H-genome DNA of H. chilense. Different signals were observed between species from North American and that from Asian. The result indicates that StH genome in North American varied from those in Asian.3. In four accessions of E. tangutorum,14chromosomes and the short arm of2chromosomes show yellow fluorescence when probing with H-genome DNA of H. chilense and blocking with St-genome DNA of P. strigosa ssp. aegilopoides. The result indicates that the four accessions of E. tangutorum contain the H genome from Hordeum. When probing with St-genome DNA of P. strigosa ssp. aegilopoides and blocking with H-genome DNA of H. chilense,14chromosomes show yellow fluorescence in E. tangutorum. The result suggests that E. tangutorum contain contain the St genome from Pseudoroegneria. When probing with StY-genome DNA of R. japonensis and blocking with H-genome DNA of H. chilense,28chromosomes show yellow fluorescence signals in E. tangutorum. The result suggests that E. tangutorum contain the StY genome from Roegneria. Thus, it is concluded from GISH results that E. tangutorum contain the StYH genomes.