CHROMOSOMAL LOCATION AND EXPRESSION OF A HERBICIDE SAFENER-REGULATED GLUTATHIONE-S-TRANSFERASE GENE IN TRITICUM-AESTIVUM AND LINKAGE RELATIONS IN HORDEUM-VULGARE

The chomosomal location of a glutathione S-transferase (GST) gene was determined in both hexaploid wheat (Triticum aestivum) and barley (Hor deum vulgare). The GST cDNA used to map the gene was cloned from the d iploid wheat Triticum tauschii. GST loci were located on the short arm s of chromosomes 6A, 6B, and 6D in T. aestivum and also on the short a rm of chromosome 6H in H. vulgare. The GST locus in barley was absolut ely linked to the RFLP marker E148A and was located 0.8 cM proximal to the RFLP marker ABC169B on barley chromosome 6H. At least two copies of the GST gene were present in each of the T. aestivum A, B, and D ge nomes, and a homologous GST gene was present as a single-copy gene in the barley genome. GST mRNA transcripts were not detected in RNA isola ted from shoots of control (unsafened) seedlings of T. tauschii or T. aestivum. It was determined that the expression of the GST gene was re gulated by herbicide safener treatment in T. tauschii and T. aestivum by detecting safener-increased GST mRNA transcript levels.