Detection and analysis of UV-induced mutations in the chromosomal DNA of Arabidopsis

• Published in: Biochemical and biophysical research communications 2021-05, Vol.554, p.89-93
• Main Authors: Nakamura, Munehisa, Nunoshiba, Tatsuo, Hiratsu, Keiichiro
• Format: Article
• Language: English
• Subjects: Arabidopsis; Mutation spectra; Photoreactivation; supF; UV-induced mutation
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2021.03.087

Under natural conditions, plants are exposed to solar ultraviolet (UV) radiation, which damages chromosomal DNA. Although plant responses to UV-induced DNA damage have recently been elucidated in detail, revealing a set of DNA repair mechanisms and translesion synthesis (TLS), limited information is currently available on UV-induced mutations in plants. We previously reported the development of a supF-based system for the detection of a broad spectrum of mutations in the chromosomal DNA of Arabidopsis. In the present study, we used this system to investigate UV-induced mutations in plants. The irradiation of supF-transgenic plants with UV-C (500 and 1000 J/m2) significantly increased mutation frequencies (26- and 45-fold, respectively). G:C to A:T transitions (43–67% of base substitutions) dominated in the mutation spectrum and were distributed throughout single, tandem, and multiple base substitutions. Most of these mutations became undetectable with the subsequent illumination of UV-irradiated plants with white light for photoreactivation (PR). These results indicated that not only G:C to A:T single base substitutions, but also tandem and multiple base substitutions were caused by two major UV-induced photoproducts, cyclobutane-type pyrimidine dimers (CPDs) and pyrimidine (6-4) pyrimidone photoproducts (6-4 PPs). In contrast, a high proportion of A:T to T:A transversions (56% of base substitutions) was a characteristic feature of the mutation spectrum obtained from photoreactivated plants. These results define the presence of the characteristic feature of UV-induced mutations, and provide insights into DNA repair mechanisms in plants. •The supF system was used for the analysis of UV-induced mutations in plants.•The irradiation of supF-transgenic plants with UV-C increased mutation frequencies.•G:C to A:T transitions dominated in the mutation spectrum of base substitutions.•Most of the UV-induced mutations became undetectable by photoreactivation.•High proportion of A:T to T:A is a distinctive feature in photoreactivated plants.