The Development And Characterization Of Chromosome Translacation Between Wheat And Haynaldia Villosa

Wheat production and quality are affected by biotic stresses seriously, and the improvement of the resistance of diseases and pests, and the adaptability to various environments are the main objectives of modern wheat breeding. Haynaldia villosa L. Schur, a wild relative of wheat, is an important and useful gene resource for wheat improvement, such as resistance to diseases including powdery mildew, rusts, wheat yellow mosaic virus (WYMV), take-all, eyespot, as well as tolerance to drought, good tiller ability, and high grain protein content. And it reported that chromosome 4V of H. villosa has resistance genes to eyespot, take-all, WYMV, and salt tolerance as well as genes encoding α-prolamins. The development of translocations with small alien segments, especially interstitial translocations, which contain minimized unfavorable genes, will be helpful for better utilization of alien genes. In this research, the CS ph1b mutant and irradiation were used to induce chromosome aberrations involving chromosome 4V of H. villosa. New translocations with shortened 4V chromosome fragments were developed and identified through cytogenetics and molecular markers analysis.1. Development of specific markers for chromosome 4V of H. villosaFor rapid and accurate identification of chromosome aberrations involving chromosome 4V of H. villosa, in the present study,146 primer pairs were designed according to the EST sequences and 80 primer pairs of PLUG. Total of 226 primer pairs were used for amplification using the genomic DNA of Chinese spring, H. villosa, T. durum-H. villosa amphiploid, T4DL-4VS, T5DL-4VL and T. aestivum-H villosa disomic addition lines DA1V-DA7V. Among them,39 primer pairs could amplify specific bands for chromosome 4V, and 21 specific markers for 4VS which contain 2 EST primer pairs and 19 PLUG primer pairs; 18 specific markers were assigned to the long arm of chromsome 4V, which contain 7 EST primer pairs,11 PLUG primer pairs. By amplification using the Chinese Spring (CS) nulli/tetrasomic lines N4AT4B and N4DT4B, 19 of the 39 EST-PCR specific markers were physically mapped to wheat group 4 chromosomes, confirming the homoeologous relationship of chromosome 4V with wheat group 4 chromosomes. These 4V specific markers provided efficient tools for the characterization of chromosome aberrations involving the chromosome 4V as well as for the localization of useful genes on chromosome 4V.2. Induction of 4VL chromosome aberrations using the CS phlb mutant and irradiationIn the study, the disomic substitution line 4V(4D)were crossed to the CS phlb mutant followed by backcrossing of the F1 plants to CS phlb mutant, and the derived BC1F2 were screened by genomic in situ hybridization (GISH) and molecular markers to identify 4VL recombinants. We got 4 interstitial translocations and 1 terminal translocation..44 molecular markers located in 4VL were used to determine the fragment sizes and breakpoints of the alien chromosomes in the 5 newly developed translocation lines, which hence could be grouped into 4 different types. By FISH analysis using pSc 119.2 and pAsl as probes, the wheat chromosomes involved in the translocated chromosomes were all chromosome 4D, indicating these compensatory translocations were resulted from homoleogous recombination induced by the CS ph1b mutant.3. Induction of 4VL chromosome aberrations through irradiationThen, we use 60Co-y ray irradiated the pollen of disomic substitution line 4V (4D) before flowering in 2012, and then crossed to common wheat variety Yangmai 158. We got 160 M1 plants. Then the M1 plants were screened by GISH to detect the chromosome aberrations involving 4V. The identified individuals were backcrossed or self-crossed. In the derived progenies,17 chromosome aberrations involving 4V were identified by GISH, including 9 telomere chromosomes,3 terminal translocation chromosomes,1 interstitial translocation chromosomes,4 large fragment translocation. And there are 3 aberrations of 4VL chromosome, which contained one terminal translocation, one long arm translocation and one large fragment translocation.4. Construction of alien chromosome aberrance library for chromosome arm 4VL of H. villosaBy CS ph1b and irradiation, a total of 7 chromosome aberrations involving the chromosome arm 4VL were obtained. These chromosome structural aberrations are very useful for constructing structural aberrance library and physical mapping of genes identified on chromosome 4VL. Based on above studies,44 specific molecular markers for the long arm of chromosome 4V were further allocated to 9 different regions.