Plant Photoreceptors and Photomorphogenesis
Han, In-Seob , Eisinger, William , Briggs, Winslow .
On the Light-Activated Subcellular Wanderings of Phototropic 1-GFP (phot1-GFP).
Recent work with Arabidopsis thaliana indicates that a red-light pulse, perceived through phytochrome A, increases the phototropic sensitivity of etiolated seedlings measured after a 2 h dark period (B. M. Parks et al., Plant Physiol. 110:155, 1996).We showed previously that a blue light pulse induces movement of phot1-GFP from the plasma membrane to the cytoplasm in cortical cells of the elongating region of etiolated A. thaliana hypocotyls. We present the time course and fluence requirements for this response. A red light pulse given immediately after the blue-light pulse has no effect. However, if a 2-h dark period intervenes between red and blue-light treatment, the blue-light effect is cancelled. This effect is far-red reversible. We present the time course and fluence requirements for this red light effect and the time course for its escape from far-red photoreversibility. The red light effect appears restricted to cells in the elongating regions of the hypocotyl. Our working hypothesis is that the blue light-induced movement of phot1 away from the plasma membrane desensitizes the seedling to unilateral blue light by moving phot1 away the auxin transport system. Red light then presumably prevents this desensitization, by causing phot1 to remain at the plasma membrane.
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1 - Universityof Ulsan, Dept. Biological Sciences, Ulsan, Korea
2 - University of Santa Clara, Dept Biology, 500 El Camino Real, Santa Clara, CA, 95053, USA
3 - Carnegie Institute of Washington, Department of Plant Biology, 260 Panama Street, Stanford, California, 94305-1297, USA
etiolated hypocotyl cortical cells.
Presentation Type: Symposium or Colloquium Presentation
Location: Boulevard C/Hilton
Date: Monday, July 9th, 2007
Time: 9:30 AM