UV-B exposure, ROS, and stress: inseparable companions or loosely linked associates?

• Published in: Trends in plant science Vol. 18; no. 2; pp. 107 - 115
• Main Authors: Hideg, Éva, Jansen, Marcel A.K, Strid, Åke
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2013
• Subjects: acclimation; antioxidant; antioxidants; Antioxidants - analysis; Antioxidants - metabolism; Antioxidants - radiation effects; Biochemistry; Biokemi; Environment; gene expression; genes; loci; metabolism; Plants - metabolism; Plants - radiation effects; reactive oxygen species; Reactive Oxygen Species - analysis; Reactive Oxygen Species - metabolism; Reactive Oxygen Species - radiation effects; ROS; Signal Transduction - radiation effects; signaling; stress; Stress, Physiological - radiation effects; ultraviolet radiation; Ultraviolet Rays; UV-B; UV-B; stress; antioxidant; signaling; acclimation; ROS
• ISSN: 1360-1385; 1878-4372; 1878-4372
• DOI: 10.1016/j.tplants.2012.09.003

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.