Molecular Cytogenetic Characterization Of New Wheat-Thinopyrum Intermedium Ssp Trichophorum Germplasms

Thinopyrum intermedium (Host) B.D., a hexaploid species (2n=6X=42,E₁E₂St orJJJ^sJ^sSS), is an impotant source for improving genetic variability of cultivated wheat. Desirable characteristics of Th. intermedium of potential valuable for wheat improvement include perennial habit, stress tolerance and disease resistance (rusts and viral diseases). There was lack of studies on the pubescent subspecies, Thinopyrum intermedium ssp. trichophorum. To broaden the genetic diversity of wheat, new wheat Th. -Trichophorum germplasms including partial amphiploid TE-3 and a wheat - Th. trichophorum derivatives Y176 were produced by chromosomal manipulation. In the present study, Gliad in and glutenin electrophoresis, Random amplified polymorphic DNA (RAPD), Sequence characterized amplified region (SCAR), Chromosome C-banding and Genomoic in situ Hybridization (GISH) analysis were used to characterize the new dermplasm. and the main results are showed as following:1. Analyzed by the composition of gliadin and glutenin, Th. Trichophorum partial amphiploid TE-3, Y176 and Chinese Spring. It was indicatede that some characteristic gliadin bands from Th. Trichophorum were expressed in the TE-3 and some of Y176. The specific protein bands of showed the useful biochemical marker for tracing the incorporation of the alien chromatin.2. Three specific primers OPM04, OPH20 and OPH18 showing the Th. Trichophorum specific bands were selected from 80 random primers by RAPD analysis. One of the primer OPM04, can amplify a specific band from Th. Tichophorum, which was furtherly confirmed to amplify the St genome of Th. Trichophorum. This specific band of RAPD marker from OPM04 was isolated and cloned, and showed the size of 1430bp (Gene bank number: AY618664). Based onthe sequence, one pair of primers PI and P2 was designed, synthesized and used to amplify the above germplasms, which resulted in the similar results of RAPD analysis. It is indicated the RAPD marker OPM04i423 was successfully transferred to SCAR marker. The present SCAR were consequently used to identify our v/heat-Thinopyrum derivatives.3. One of advanced line Y176-3 with high resistance to stripe rust was obtained to subsequently cytogical descriptoion based on the existence of the specific protein bands and SCAR marker. Cytogenetic analysis showed that the Y176-3 has the chromosome number of is 44 in moititic root-tip cell, including four satellite chromosomes. The observation of meiotic chromosome configuration of PMCs was 22 bivalents. Giemsa-C banding showed the two smaller chromosomes of Th. Trichophorum with tolemeric bands.4. In order to reveal the genomic distribution of the added chromosomes of Y176-3, the Genomic in situ hybridization (GISH) was carried out by using the St genome a probe, and the common wheat genomic DNA as a blocker. The results indicated that the introduced Th. Trichophorum chromosomes are belongs to St genomes. Terefore, it is Concluded that the target St chromosomes of Th. Trochophorum was responsible for the specific protein bands and the rust resistance.