Seeing the unseen: How plants sense UV-B

Sunlight not only drives photosynthesis, but also provides cues to regulate plant growth and development. Termed photomorphogenesis, this ability to modulate development in response to changes in light is key to plant survival. Plants have evolved several photoreceptors to perceive and respond to different wavelengths of light found in the daylight spectrum. The majority of plant photoreceptors are proteins with a bound chromophore, a non-protein component that captures photon energy from a particular wavelength of light and converts it into a signal by inducing conformational changes in the protein itself. The resulting changes in the protein activate a signal cascade, which in turn produces alterations in gene expression, allowing the plant to adapt to the light environment. This article discusses what is known about a novel plant photoreceptor, UVR8, and the signalling pathway it activates.