UV-B exposure, ROS, and stress: inseparable companions or loosely linked associates?
Ultraviolet-B (UV-B) radiation has long been perceived as a stressor. However, a conceptual U-turn has taken place, and UV-B damage is now considered rare. We question whether UV-stress and UV-B-induced reactive oxygen species (ROS) are still relevant concepts, and if ROS-mediated signaling contributes to UV-B acclimation. Measurements of antioxidants and of antioxidant genes show that both low and high UV-B doses alter ROS metabolism. Yet, there is no evidence that ROS control gene expression under low UV-B. Instead, expression of antioxidant genes is linked to the UV RESISTANCE LOCUS 8 pathway. We hypothesize that low UV-B doses cause 'eustress' (good stress) and that stimuli-specific signaling pathways pre-dispose plants to a state of low alert that includes activation of antioxidant defenses.
Institute of Biology, University of Pécs, Ifjuság u. 6. H-7624 Pécs, Hungary.
Eva
E
Hideg
Marcel A K
MA
Jansen
Ake
A
Strid
D000975:Antioxidants / Q000032:analysis / Q000378:metabolism / Q000528:radiation effects; D004777:Environment; D010944:Plants / Q000378:metabolism / Q000528:radiation effects*; D017382:Reactive Oxygen Species / Q000032:analysis / Q000378:metabolism / Q000528:radiation effects*; D015398:Signal Transduction / Q000528:radiation effects; D013312:Stress, Physiological / Q000528:radiation effects*; D014466:Ultraviolet Rays
D000975:Antioxidants; D017382:Reactive Oxygen Species