| Popis: |
During the 30 years since its initial isolation, a great body of information has accumulated concerning the structure of phytochrome, the physiological responses it controls, and the genes whose expression it affects, yet little is known about the molecular mechanisms of phytochrome action. The recent advent of technologies allowing the expression of heterologous phytochrome genes in transgenic plants provide an important new method for research into the mechanisms of phytochrome action (Keller et al., 1989; Boylan and Quail, 1989; Kay et al., 1989). In the first report of this approach, Keller et al. (1989) described the expression of a functional oat phytochrome in tobacco. Transgenic plants expressing the oat protein have a radically altered phenotype characterized by decreased stem elongation, increased leaf chlorophyll content, reduced apical dominance, and delayed leaf senescence. Exploiting this “light-exaggerated” phenotype as an assay, it is now possible to identify and examine domains involved in phytochrome structure and function by in vitro mutagenesis. |
