Title: “Uncovering a role for phyB-photobody formation in light, temperature, and circadian signaling”
Host: Dawn Nagel
Abstract: Cellular contents are organized to enable spatial control over signaling pathways, both through the formation of membrane-associated organelles and self-organized biomolecular domains. In plants, the red-light photoreceptors known as phytochromes (phys) form subnuclear, micron-sized foci called photobodies (PB) after exposure to activating red light. PBs dissipate after plants are exposed to dark, far-red light, or elevated temperatures. PB formation by phyB has been correlated with the regulation of plant growth in response to day-to-night transitions and seasonal changes in photoperiod. Despite evidence that PBs are critical for prolonged phyB signaling, whether PBs function to encapsulate active phyB or are important centers for signaling is unclear. This is due in part to limited knowledge of the structural components of photobodies. We find that PHOTOPERIOD CONTROL OF HYPOCOTYL ELONGATION 1 (PCH1) functions as a structural component of phyB-PBs and reveal that PB formation is necessary for photomorphogenesis, thermo-perception and signaling into the circadian clock in Arabidopsis thaliana. Our work extends our understanding of the role of photobodies in the control of plant physiology in response to changing environments.