Mapping of the seed storage protein locus Sec-2 in rye

A rapid antibody-based test for Sec-2, a marker for the short arm of chromosome 2 of rye (2RS)

A simple monoclonal antibody-based screening test has been developed for the presence of translocations of the short arm of chromosome 2 of rye (2RS) with wheat chromosome 2B. 2RS encodes a set of about three polypeptides known as Mr 75 000 gamma-secalins. Use of the antibody test for these secalins enabled screening of several hundred seeds per day. The antibody could readily distinguish 2BL–2RS translocations and 2R substitutions from 1BL–1RS translocations or nontranslocation wheats. Use of the antibody in analysis of segregating progeny for Sec-2 in several wheat backgrounds was successful. Results with a selection of the seed population were checked using protein gel electrophoresis, with 100% correct confirmation. Key words : rye, wheat, seed proteins, translocation, diagnostic test.

Genetic mapping of cytological and isozyme markers on chromosomes 1R, 3R, 4R and 6R of rye

Cytogenetic maps involving chromosomes 1R, 3R, 4R and 6R have been developed from the analysis of offspring of crosses between multiple heterozygous rye plants. The maps include isozyme loci GpiR1, Mdh-R1 and Pgd2 (located in chromosome 1R), Mdh-R2 (located in chromosome 3R), Pgm-R1 (located in chromosome 4R) and Aco-R1 (located in chromosome 6R). Various telomeric and interstitial C-bands of these four chromosomes, the centromere split of chromosome 3R, and translocation TR01 were used as cytological markers. By means of electron microscope analysis of spread pachytene synaptonemal complexes, the breakpoint of TR01 was physically mapped in chromosome arms 4RS and 6RL. From the linkage data, conclusions were derived concerning the cytological locations of the isozyme loci and the physical extent of the evolutive translocations involving chromosome arm 6RL.

Restriction fragment analysis of the secalin loci of rye

Analyses of wheat/rye addition lines by Southern blotting confirmed the presence of sequences related to the Sec 1, Sec 2, and Sec 3 loci on chromosomes 1R and 2R. Comparison of the 1R and 2R addition lines allowed the identification of gamma-secalin genes at Sec 1 and Sec 2, respectively, while omega-secalin and gamma-secalin genes at Sec 1 were discriminated by comparative hybridization with three probes: omega-secalin, total gamma-secalin, and 3' gamma-secalin. The high molecular weight (HMW) secalin genes at Sec 3 were identified using a homologous HMW subunit probe from wheat. Gene copy numbers were estimated as about 40-60 for omega-scalins, 5-10 for gamma-secalins, and 2 for HMW secalins. Comparison of individual plants of cv. Gazelle showed a high degree of polymorphism, particularly for sequences related to omega-secalins and HMW secalins.