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

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.
Source: Plant and Cell Physiology - Category: Cytology Authors: Tags: Regular Papers Source Type: research