Temporal and spacial distribution of mannopine synthase ( mas ) promoter activity was determined throughout the development of transgenic tobacco plants using bacterial luciferase luxA and luxB as reporter genes. Luciferase activity was determined by luminometry in vitro and visualized by computer-enhanced single-photon video imaging in vivo . The activity of the mas dual promoters increased basipetally in developing plants and was wound-inducible in leaf and stem tissue. Hormone bioassays with isolated plant tissues and tumors deficient in the transferred DNA (T-DNA)-encoded genes iaaM, iaaH , and ipt indicated that activity of the mas dual promoters is regulated by auxin and enhanced by cytokinin in both differentiated and tumorous plant cells.