Understanding How Plants Sense Ultraviolet Light
Sunlight is essential for plant development and growth, yet many details of the mechanisms by which plants respond to sunlight are poorly understood. A recent study published in Science provides new information about the molecular changes initiated by exposure to the UV-B portion of sunlight. The research used small-angle x-ray scattering (SAXS) experiments to characterize how the plant photoreceptor UVR8 changes shape when exposed to UV-B radiation. Two UVR8 molecules are complexed together as a dimer in plant cells and break apart on exposure to UV-B. The separate molecules then interact with a series of proteins in the cell to signal the presence of solar radiation. A specific mutation in UVR8 was found to “retune” the molecule’s response from UV-B to UV-C radiation. The results will be useful in understanding how to optimize biomass crop growth. The SAXS studies were carried out at the SIBYLS experimental station at the Advanced Light Source at the Berkeley Lab. The study was led by Elizabeth Getzoff of the Scripps Research Institute.
Christie, J. M., et al. 2012. “Plant UVR8 Photoreceptor Senses UV-B by Tryptophan-Mediated Disruption of Cross-Dimer Salt Bridges,” Science 335, 1492-1496. DOI: 10.1126/science.1218091.