UV-B-Induced CPD Photolyase Gene Expression is Regulated by UVR8-Dependent and -Independent Pathways in Arabidopsis

• Published in: Plant and cell physiology Vol. 56; no. 10; pp. 2014 - 2023
• Main Authors: Li, Nan, Teranishi, Mika, Yamaguchi, Hiroko, Matsushita, Tomonao, Watahiki, Masaaki K, Tsuge, Tomohiko, Li, Shao-Shan, Hidema, Jun
• Format: Journal Article
• Language: English
• Published: Japan 01.10.2015
• Subjects: Arabidopsis - metabolism; Arabidopsis - radiation effects; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Chromosomal Proteins, Non-Histone - genetics; Chromosomal Proteins, Non-Histone - metabolism; Deoxyribodipyrimidine Photo-Lyase - genetics; Deoxyribodipyrimidine Photo-Lyase - metabolism; Gene Expression Regulation, Plant - radiation effects; Signal Transduction - radiation effects; Ultraviolet Rays; UVR8; CPD photolyase; Cyclobutane pyrimidine dimer (CPD); Cryptochrome; Gene expression; Arabidopsis
• ISSN: 0032-0781; 1471-9053
• DOI: 10.1093/pcp/pcv121

Plants have evolved various mechanisms that protect against the harmful effects of UV-B radiation (280-315 nm) on growth and development. Cyclobutane pyrimidine dimer (CPD) photolyase, the repair enzyme for UV-B-induced CPDs, is essential for protecting cells from UV-B radiation. Expression of the CPD photolyase gene (PHR) is controlled by light with various wavelengths including UV-B, but the mechanisms of this regulation remain poorly understood. In this study, we investigated the regulation of PHR expression by light with various wavelengths, in particular low-fluence UV-B radiation (280 nm, 0.2 µmol m(-2) s(-1)), in Arabidopsis thaliana seedlings grown under light-dark cycles for 7 d and then adapted to the dark for 3 d. Low-fluence UV-B radiation induced CPDs but not reactive oxygen species. AtPHR expression was effectively induced by UV-B, UV-A (375 nm) and blue light. Expression induced by UV-A and blue light was predominantly regulated by the cryptochrome-dependent pathway, whereas phytochromes A and B played a minor but noticeable role. Expression induced by UV-B was predominantly regulated by the UVR8-dependent pathway. AtPHR expression was also mediated by a UVR8-independent pathway, which is correlated with CPD accumulation induced by UV-B radiation. These results indicate that Arabidopsis has evolved diverse mechanisms to regulate CPD photolyase expression by multiple photoreceptor signaling pathways, including UVR8-dependent and -independent pathways, as protection against harmful effects of UV-B radiation.