Development And Characterization Of A Complete Set Of Triticum Aestivum-Roegneria Ciliaris Disomic Addition Lines

Wild relatives are rich gene resources for cultivated wheat.Introduction of alien genes by the development of alien chromosome lines can broaden the genetic diversity.The developed alien chromosome lines also provide genetic Stocks for comparative genomic Study.Roegneria ciliaris(2n=4x=28,genome ScScYcYc)is a tetraploid wild relative of wheat.It has been reported possessing many useful traits,especially tolerances and resistances to different abiotic and biotic stresses.Efforts have been made to the development of alien chromosome lines since early 1980s,and several wheat-R.ciliaris addition lines have been characterized.However,the development of a complete set of addition lines has been hindered by tetraploid nature of R.ciliari,the presence of cytoplasmic effect and preferential chromosome transmission,unknown origin of the genome Yc,and low efficiency in differentiation of the Sc and Yc chromosomes.In this study,by establishing a high efficient and improved resolution of technique platform including FISH and molecular marker analysis for the identification of R.ciliaris chromosomes,we developed a complete set wheat-R.ciliaris disomic addition lines.In this research,based on the previous work,a complete set of wheat-R.ciliaris disomic addition lines was developed and characterized by molecular cytogentics,molecular markers analysis and morphological investigations using a population derived of a cross between wheat var.Chinese Spring(CS)and Triticum aestivum cv.Inayama komugi(Ik)-R.ciliaris amphiploid.The main research results obtained were as follows:1.Development and identification of a set of wheat-R.ciliaris disomic addition linesIn previous study,we have developed wheat-R.ciliaris disomic addition lines involving chromosome 1Sc,1Yc,2Sc,3Sc,5Yc,7Sc and 7Yc.By molecular marker analysis,GISH and FISH were used to identify R.ciliaris chromosomes in wheat background,and the remained seven wheat-R.ciliaris disomic addition lines(DA2Yc,DA3Yc,DA4Sc,DA4Yc,DA5Sc,DA6Sc and DA6Yc)were identified.We accomplish the development of a complete set of wheat-R.ciliaris disomic addition lines,and each added a pair of the 14 R.ciliaris chromosomes.2.FISH pattern of R.ciliaris chromosomes using repetitive DNA sequencesSequential GISH and FISH analysis was used to characterize wheat-R.ciliaris disomic addition lines by using the genomic DNA of R.ciliaris,the repetitive DNA sequences pAs1,pSc 119.2 and 45S rDNA as probes.The results showed the pAsl signals were detected on 10 of 14 R.ciliaris chromosomes(1Sc,2Sc,3Sc,4Sc,6Sc,7Sc,1Yc,2Yc,4Yc and 7Yc).The signals mainly distributed at terminal,subterminal and interstitial regions.The signals were only detected on the long arm of 2Sc,7Sc and 4Yc.No obvious signal was observed on the all R.ciliaris chromosomes when using pScl19.2 as probe.The 45S rDNA signals were localized on the short arm of 1Sc and 5Sc.More cytological probes need to be developed for distinguishing chromosoemes 3Yc,5Yc and 6Yc because no FISH signal was observed on these chromosomes when using pAs1,pSc119.2 and 45S rDNA as probes.3.Development and chromosome assignment of molecular markers specific R.ciliaris chromosomesMolecular markers provide a rapid approach for accurate identification of R.ciliaris chromosomes added into wheat background.In the present study,a total of 1845 primer pairs previously mapped to the seven homoeologous groups of wheat were used and amplified in CS,Inayama komugi,Ik-R.ciliaris amphiploid and R.ciliaris.Among them,557 could produce specific amplicons in R.ciliaris,and they were used for amplification in the complete set of disomic addition lines.One hundred and seven markers were allocated to 14 R.ciliaris chromosomes,in which 22 to 1Sc,3 to 1Yc,3 to 2Sc,7 to 2Yc,2 to 3Sc,6 to 3Yc,12 to 4Sc,7 to 4Yc,6 to 5Sc,12 to 5Yc,9 to 6Sc,9 to 6Yc,1 to 7Sc and 8 to 7Yc,respectively.Fifty-four markers are codominant for the two R.ciliaris genomes and can be used to distinguish homoeologous chromosomes from the Sc and Yc genomes.4.Characterization of the disease resistances and agronomic performances of wheat-R.ciliaris disomic addition lines Wheat-?.ciliaris,disomic addition lines together with their parents were evaluated for resistances to Fusarium head blight(FHB),powdery mildew,wheat yellow mosaic virus and leaf rust.The results indicated that,compared with the wheat parents,Ik-R.ciliaris amphiploid showed certain resistances to the above three diseases at specific growth stages.Four years' evaluation for FHB resistance showed that the amphiploid was stable resistant to FHB,lines DAI Sc(3 years data),DA1Yc,DA2Yc,DA3Sc(3 years data),DA4Sc,DA5Yc and DA6Sc were resistant to FHB;Four years' field evaluation for powdery mildew resistance at adult stage showed that the amphiploid was resistant to powdery mildew,lines DA1Sc(3 years data),DA2Sc,DA2Yc,DA3Yc(3 years data),DA5Sc,DA5Yc and DA6Sc were moderately resistant to powdery mildew;Three years' field evaluation for wheat yellow mosaic virus resistance showed that the amphiploid was resistant,and lines DA5Sc(1 years data)and DA6Sc were highly resistant to wheat yellow mosaic virus;Two years'field evaluation for leaf rust resistance showed that the amphiploid was resistant,and lines DA5Yc and DA6Sc were highly resistant to leaf rust.To summarize,lines DA1Sc,DA5Sc,DA5Yc and DA6Sc were resistant to 2 or more than 2 different wheat diseases.Phenotypic investigation showed that these addition lines showed significant difference for their morphology in plant architechtures.The developed disomic addition lines should be new germplasms to broaden the genetic diversity of wheat.