Genetic polymorphisms in mutagenesis progeny of Arabidopsis thaliana irradiated by carbon-ion beams and γ-rays irradiations

Purpose: Heavy-ion beams and gamma-rays are popular physical mutagenesis to generate mutations in higher plants. It has been found that they show different mutation frequencies and spectrums of phenotype induction, however, the characteristics of heavy-ion beams on genetic polymorphism have not been clarified by comparing with gamma-rays. Materials and methods: In the present study, seeds of Arabidopsis thaliana were exposed to carbon-ion beams (with linear energy transfer (LET) of 50 keV/mu m) and gamma-rays (with average LET of 0.2 keV/mu m) irradiation. By using inter-simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD) analysis, the genetic polymorphism of both M-1 and M-3 plants were investigated, respectively. Results: Carbon-ion beams induced relatively higher polymorphism rate in both M-1 and M-3 generation than gamma-rays: the polymorphism rates of M-1 plants derived from carbon-ion beams irradiation are 12.87% (ISSR-C) and 9.01% (RAPD-C), while are 7.67% (ISSR-gamma) and 1.45% (RAPD-gamma) of plants derived from gamma-rays. In M-3 generation, the polymorphism rates of ISSR-C, RAPD-C, ISSR-gamma, and RAPD-gamma are 17.64%, 22.79%, 12.10%, and 2.82%, respectively. Conclusions: In summary, the exposure to carbon-ion beams and gamma-rays lead to the change of genomic DNA of A. thaliana, which could be tested in M-1 plants and M-3 plants by ISSR and RAPD technology. So, both carbon-ion beams and gamma-rays can induce variations of genetic polymorphisms in M-1 plants and M-3 plants. The genetic polymorphisms of M-1 plants and M-3 plants induced by carbon-ion beams are higher than gamma-rays, indicating that heavy-ion beams irradiations mutation breeding is more advantageous than conventional ionizing radiations. Average molecular polymorphism of M-1 plants is lower than M-3 mutants, by nearly 4.77% (ISSR-C), 13.78% (RAPD-C), 4.43% (ISSR-gamma), and 1.37% (RAPD-gamma). We hope our study will provide basic information for understanding the effects of carbon-ion beams and gamma-rays for plant mutation breeding.