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 t ranslocation lines and a specific assay for 1BL.1RS lines, separate mo noclonal antibodies (mAbs) were isolated that recognised M(r) 40 000 g amma-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 transl ocated onto either chromosome 1A, 1B or 1D, while non-translocation wh eats 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 struct ure since the antibody response was abolished if the proteins were red uced. MAb 218/17 displayed little reaction with aqueous propan-2-ol ex tracts of 1BL.1RS translocation lines, but gave a positive colour resp onse with all other wheats tested. Therefore detection of 1BL.1RS tran slocation lines can be achieved by a positive response to mAb 808/10 o r a negative response to mAb 218/17. Alternatively, both ELISAs can be performed on a single aqueous propan-2-ol sample extract to different iate 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 translo cations in American and Australian backgrounds. These ELISAs have seve ral advantages over other immunoassays for Gli-B1 gliadins or Sec-1 se calins. They include reduced assay time because of fewer steps, enabli ng greater throughput of samples, and adaptability to meal, flour or h alf-grain samples. (C) 1996 Academic Press Limited