Development and characterization of structural changes in chromosome 3Hch from Hordeum chilense in common wheat and their use in physical mapping

Said M., Recio R., Cabrera A.
EUPHYTICA 188: 429-440, 2012

Keywords: Barley, Fluorescence in situ hybridization, Physical location, Structural changes
Abstract: Structural changes in Hordeum chilense chromosome 3Hch were obtained in common wheat background by crossing tritordeum (the fertile amphiploid H. chilense–T. turgidum, 2n = 6x = 42, AABBHchHch) with the disomic addition line of chromosome 2Cc from Aegilops cylindrica in common wheat cv. ‘Chinese Spring’ (CS). Hybrid plants (2n = 43, AABBDHch + 2Cc) monosomic for the gametocidal chromosome were crossed with common wheat both CS and Anza. Rearranged 3Hch chromosomes were identified and cytologically characterized by FISH using both pAs1 repetitive sequence and genomic H. chilense DNA as probes. Two deletions on the short and long arm respectively, (del3HchS and del3HchL) and two reciprocal centromeric translocations involving chromosome 3Hch and 3D were identified. The breakpoints (FL) in the deleted chromosomes were determined as 56 % in del3HchS and 42 % in del3HchL, respectively. In order to obtain homozygous plants for rearranged 3Hch chromosomes the derived progenies were self-pollinated for four generations and the following lines were established: (1) disomic substitution DS-del3HchS(3D) (2n = 42) in CS; (2) disomic addition DA-del3HchL (2n = 44) in Anza; (3) homozygous translocation T3HchS•3DL (2n = 42) in CS, and (4) homozygous translocation T3DS•3HchL (2n = 42) in CS. These four lines were morphologically and agronomically characterized under field conditions. All lines were fertile, stable and vigorous. The four lines obtained were used to develop specific DNA markers for chromosome 3Hch in wheat. We studied the applicability of 162 barley chromosome 3H primers (55 genomic-SSRs, 17 genomic-STSs, 66 EST-SSRs and 24 EST-SNPs) to amplify markers showing polymorphism between H. chilense and common wheat. A total of 53 (32.7 %) markers gave reliable amplifications in H. chilense and among them 31 (19.1 %) were polymorphic between H. chilense and CS and Anza. Eighteen of the 31 polymorphic loci were mapped onto different chromosome sub-arm regions of chromosome 3Hch. Arm locations of these markers on barley chromosome 3H were determined using wheat–barley ditelosomic lines for 3HS and 3HL arms. The comparative positions of these markers in H. chilense and H. vulgare are discussed. IEB authors: Mahmoud Said