Efficient removal of cyclobutane pyrimidine dimers in barley: differential contribution of light‐dependent and dark DNA repair pathways

Abstract

Barley stress response to ultraviolet radiation (UV) has been intensively studied at both the physiological and morphological level. However, the ability of barley genome to repair UV-induced lesions at the DNA level is far less characterized. In this study, we have investigated the relative contribution of light-dependent and dark DNA repair pathways for the efficient elimination of cyclobutane pyrimidine dimers (CPDs) from the genomic DNA of barley leaf seedlings. The transcriptional activity of barley CPD photolyase gene in respect to the light-growth conditions and UV-C irradiation of the plants has also been analyzed. Our results show that CPDs induced in the primary barley leaf at frequencies potentially damaging DNA at the single-gene level are removed efficiently and exclusively by photorepair pathway, whereas dark repair is hardly detectable, even at higher CPD frequency. A decrease of initially induced CPDs under dark is observed but only after prolonged incubation, suggesting the activation of light-independent DNA damage repair and/or tolerance mechanisms. The green barley seedlings possess greater capacity for CPD photorepair than the etiolated ones, with efficiency of CPD removal dependent on the intensity and quality of recovering light. The higher repair rate of CPDs measured in the green leaves correlates with the higher transcriptional activity of barley CPD photolyase gene. Visible light and UV-C radiation affect differentially the expression of CPD photolyase gene particularly in the etiolated leaves. We propose that the CPD repair potential of barley young seedlings may influence their response to UV-stress.

Exogenous Cytokinin 4PU-30 Modulates the Response of Wheat and Einkorn Seedlings to Ultraviolet B Radiation

“…The fold change in the expression levels of the genes was estimated based on Pfaffl's method [97]. The 18S ribosomal RNA fragment (118 bp) was used as a reference control amplified with the following primers: HV_18Ssh1F-CCTGCGGCTTAATTTGACTCA and HV_18SR-AACTAAGAACGGCCATGCAC [98]. The genes whose expression was characterized were SOD, CAT, POX, and GST.…”

Biological impact of ultraviolet-B radiation on spider mites and its application in integrated pest management

“…Photoreactivation via repair of DNA lesions such as CPDs and 6-4 PPs via PER is essential, and the reactivation system is present in a wide range of organisms, including bacteria (Ikenaga et al 1970;Peccia and Hernandez 2001), rotifers (Grad et al 2003), crustaceans (Connelly et al 2009;Damkaer and Dey 1983;Grad and Williamson 2001), algae (Pakker et al 2000;Pescheck 2019), plants (Hada et al 2003;Kaiser et al 2009;Manova et al 2016;Takahashi et al 2002), amphibians (Blaustein et al 1994;Morison et al 2020), and fishes (Applegate and Ley 1988;Lawrence et al 2020;Mitchell et al 2009;Wiegand et al 2004), but not in placental mammals, which may rely on other repair systems: base excision repair, NER, and so on (Sinha and Häder 2002). In spider mites, Santos (2005) observed photoreactivation of UV-B damage in T. urticae, the mortality rate of T. urticae adult females irradiated with UV-B at 46.8 kJ/m 2 was reduced from 46% (when kept in the dark after UV-B irradiation) to 26% with VIS illumination after UV-B irradiation.…”