Chromosome Rearrangement Analysis And Localization Of Resistance To Stripe Rust In The Wheat-Dasypyrum Breviaristatum Introgression Line

As a related genus of wheat,Dasypyrum(or Haynaldia)has many excellent agronomic traits such as disease resistance,stress resistance,high protein content and drought tolerance,and is one of the excellent gene banks for the improvement of wheat germplasm resources.Dasypyrum.breviaristatum(genome V~b)was a species of genus Dasypyrum,and it has received widespread attention due to its unique tetraploidy and relative independence within the genus,which is still not fully studied.The successful development of wheat-D.breviaristatum partial amphiploid TDH-2 and the creation of a variety of wheat--D.breviaristatum derivatives paved conditions for the analysis of the V~b genome and excellent resistance genes of D.breviaristatum.1.The use of chromosome Oligo-FISH painting technique and fluorescence in situ hybridization(FISH)technology to determine the homologous group D.breviaristatum1V~b to 7V~b chromosomes.The huge differences of fluorescence signals between the D.breviaristatum homologous chromosomes indicated they may have widely genomic rearrangements.The FISH analysis of wheat-D.breviaristatum partial amphiploid TDH-2 revealed a large identity of the 1V~b-7V~b homologous chromosomes in the wheat background.2.The chromosome composition of wheat-D.breviaristatum introgression line A6-4 was determined by chromosome Oligo-FISH painting and non-denaturing fluorescence in situ hybridization(ND-FISH).The result showed that there is a Robertsonian translocation 7V~bL.2V~bL formed by the long arm chromosome of D.breviaristatum 2V~band the long arm of 7V~b.A higher-resolution karyotypic map of the 7V~bL.2V~bL chromosome was constructed from the ND-FISH by five novel oligonucleotide probes.The chromosome 7V~bL.2V~bL was also screened for CINAU molecular markers,in which49 of 7V~bL and 73 of 2V~bL specific markers were obtained for further chromosome segment analysis.The comparative genomic analysis of the molecular markers distributed in of 7V~bL with related chromosomes 7V(Dasypyrum.villosum),7E(Thinopyrum elongatum)and 7D(Aegilops tauschii),respectively.We found that 7V~bL in A6-4 belongs to the more ancestry genome and has higher collinearity with chromosome 7EL.3.The ND-FISH analysis of 1503 F2 population derived from wheat-D.breviaristatum introgression line A6-4 cross to wheat MY11,showed that the total frequency of 7V~bL and 2V~bL were 43.45%and 56.55%,respectively,indicating that 2V~bL was preferentially transmitted compared with 7V~bL.A total of 15 chromosome rearrangement types associated with the 7V~bL and 2V~bL,including seven exogenous chromosome 7V~bL or 2V~bL variants,and 15 translocations between chromosome 7V~bL or 2V~bL and wheat were identified.The acquisition of these materials with exogenous chromosomal variation is beneficial to the segmental analysis and gene mapping of target genes in the V~b chromosome.4.The molecular marker analysis of various 7V~bL and 2V~bL derived lines assigned the 7V~bL into 10 sections and the 2V~bL into 8 sections.The observation of agronomic traits showed that chromosome 7V~bL or 2V~bL had a dosage effect on plant height,spike length,and spikelet number.The analysis of stripe rust resistance indicated that both 7V~bL and 2V~bL had excellent stripe rust resistance,which further located the stripe rust resistance gene on chromosome 7V~b within the FL0.51-1.00 section of 7V~bL.