UV‐B responses in the spotlight: Dynamic photoreceptor interplay and cell‐type specificity

Abstract

Plants are constantly exposed to a multitude of external signals, including light. The information contained within the full spectrum of light is perceived by a battery of photoreceptors, each with specific and shared signalling outputs. Recently, it has become clear that UV‐B radiation is a vital component of the electromagnetic spectrum, guiding growth and being crucial for plant fitness. However, given the large overlap between UV‐B specific signalling pathways and other photoreceptors, understanding how plants can distinguish UV‐B specific signals from other light components deserves more scrutiny. With recent evidence, we propose that UV‐B signalling and other light signalling pathways occur within distinct tissues and cell‐types and that the contribution of each pathway depends on the type of response and the developmental stage of the plant. Elucidating the precise site(s) of action of each molecular player within these signalling pathways is key to fully understand how plants are able to orchestrate coordinated responses to light within the whole plant body. Focusing our efforts on the molecular study of light signal interactions to understand plant growth in natural environments in a cell‐type specific manner will be a next step in the field of photobiology.

Darkness inhibits autokinase activity of bacterial bathy phytochromes

“…The ability to adapt behavior and physiology to ever-changing environmental conditions was increased during evolution through the presence of receptors that absorb light from a wide variety of spectral ranges. These photoreceptors are classified into different families depending on the specific wavelength by which they are activated and the light-absorbing chromophore that is embedded in the receptor: UV light B (UV resistance locus 8, UVR8) receptors, phytochromes, rhodopsins, xanthopsins, cryptochromes, light-oxygen-voltage sensing and blue-light sensing using FAD domains containing blue light receptor proteins ( 2 , 3 , 4 ). Phytochromes are a class of red and far-red light sensing biliprotein photoreceptors ( 5 ).…”