DNA damage induced by heavy-ion beam and its repair in plant cells

Yokota, Yuichiro; Hase, Yoshihiro; Shikazono, Naoya; Funayama, Tomoo; Kobayashi, Yasuhiko; Narumi, Issei; Inoue, Masayoshi*; Tanaka, Atsushi

DNA damage and its repair mechanism in plant cells irradiated with ion beam are not revealed well. In this study, we have irradiated tobacco BY-2 cells and Chinese hamster CHO-K1 cells with -rays, He, C and Ne ions and quantified initial yields and rejoining efficiency of DNA double-strand breaks (DSBs) using pulsed-field gel electrophoresis assay. Results showed that ions induced more DSBs at closer sites of genome DNA than -rays did. This may be a part of mechanism, by which novel mutants have been acquired using ion beam in place of -rays. Our results also indicated that there is a point of difference as well as similarity in DSB yields and rejoining efficiencies between tobacco cells and mammalian cells. We point out that it is imprecise to estimate DNA damage and its repair mechanism in irradiated plant cells from the experimental data of irradiated mammalian cells.