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Efficient removal of cyclobutane pyrimidine dimers in barley: differential contribution of light‐dependent and dark DNA repair pathways
Author(s) -
Manova Vasilissa,
Georgieva Ralitsa,
Borisov Borislav,
Stoilov Lubomir
Publication year - 2016
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/ppl.12446
Subject(s) - photolyase , pyrimidine dimer , dna repair , etiolation , dna damage , biology , dna , hordeum vulgare , gene , gene expression , genomic dna , microbiology and biotechnology , biochemistry , botany , enzyme , poaceae
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.