Differentiation of wheat-rye translocation lines using antibody probes for Gli-B1 and Sec-1

In order to develop both a general screen for wheat-rye chromosome 1 translocation lines and a specific assay for 1BL.1RS lines, separate monoclonal antibodies (mAbs) were isolated that recognised M(r) 40 000 gamma-secalins (808/10) and gliadins encoded on chromosome 1B (218/17), respectively. Using aqueous propan-2-ol extracts of half grain, flour or meal and a direct enzyme linked immunosorbent assay (ELISA) format, mAb 808/10 gave a positive response with lines containing IRS translocated onto either chromosome 1A, 1B or 1D, while non-translocation wheats displayed very low reactivity. Similar results were obtained with dilute saline extracts of flour or meal. The binding of mAb 808/10 to secalins was dependent on the proteins retaining some tertiary structure since the antibody response was abolished if the proteins were reduced. MAb 218/17 displayed little reaction with aqueous propan-2-ol extracts of 1BL.1RS translocation lines, but gave a positive colour response with all other wheats tested. Therefore detection of 1BL.1RS translocation lines can be achieved by a positive response to mAb 808/10 or a negative response to mAb 218/17. Alternatively, both ELISAs can be performed on a single aqueous propan-2-ol sample extract to differentiate three groups: 1BL.1RS translocation lines, cultivars carrying 1RS on wheat chromosomes 1A (or less commonly 1D), and non-translocation wheals. The methods were assessed with sets of non-1RS and 1RS translocations in American and Australian backgrounds. These ELISAs have several advantages over other immunoassays for Gli-B1 gliadins or Sec-1 secalins. They include reduced assay time because of fewer steps, enabling greater throughput of samples, and adaptability to meal, flour or half-grain samples. (C) 1996 Academic Press Limited