DNA damage and oxidative stress induced by proton beam in Cymbidium hybrid

Abstract

We investigated the radiation damages caused by two types of proton beam and gamma ray in the Cymbidium hybrid RB001 [(C. sinensis × C. goeringii) × Cymbidium spp.] to characterize proton beam as a new mutagen for Cymbidium mutation breeding. The protocorm-like bodies (PLBs) of Cymbidium hybrid were irradiated with a 45 MeV proton beam [mean linear energy transfer (LET) = 1.461 keV· m -1 ], a 100 MeV proton beam (LET = 0.7306 keV· m -1 ), and gamma ray (LET = 0.2 keV· m -1). The PLBs treated with radiation doses of 0-100 Gy were analyzed using the comet assay and their physiological responses as indices of radiation damage. In the comet assay, the 45 MeV proton beam caused significant damage to the DNA integrity, but the 100 MeV proton beam and gamma ray showed relatively little radiation damage between the untreated control and treated PLBs. Malondialdehyde (MDA) content, an index of the indirect effects of ionizing radiation, was increased slightly by the 45 MeV proton beam with higher-LET, but highly increased by the 100 MeV proton beam with lower-LET. These results suggested that the 100 MeV proton beam caused extreme oxidative stress. Therefore, proton beam have unique characteristics in DNA mutagenesis pattern according to its LETs. Based on these results, proton beam is expected to be a useful tool for developing new mutant varieties of Cymbidium.Additional key words: comet assay, gamma ray, linear energy transfer, physiological responses Hort. Environ. Biotechnol. 56(2):240-246. 2015.

Biochemical Responses of Soybean (Glycine max L. Merr.) to Proton Beam Irradiation

“…In Pungsannamul, the MDA content increased significantly in response to increasing proton beam dose and the increase at a dose of 316 Gy was 46% compared to the control. Lipid peroxidation is a sign of oxidative damage, and the level of lipid peroxidation can be determined by measuring the MDA content, which is an end-product of lipid peroxidation, and has been used as indicator of plant membrane stress (Kim et al 2015;Lee et al 2015b). Lee et al (2015b) reported that MDA contents increased in response to increasing gamma-ray and proton beam doses, and that Cymbidium irradiated with proton beams at 100 MeV showed higher MDA contents than Cymbidium irradiated with gamma-rays.…”

“…Lipid peroxidation is a sign of oxidative damage, and the level of lipid peroxidation can be determined by measuring the MDA content, which is an end-product of lipid peroxidation, and has been used as indicator of plant membrane stress (Kim et al 2015;Lee et al 2015b). Lee et al (2015b) reported that MDA contents increased in response to increasing gamma-ray and proton beam doses, and that Cymbidium irradiated with proton beams at 100 MeV showed higher MDA contents than Cymbidium irradiated with gamma-rays. In addition, Alikamanoglu et al (2011) reported MDA content of irradiated soybean had similar tendency with that of Pungsannamul.…”

“…Chemical mutagens such as ethylmethanesulfonate (EMS), N-nitroso-N-methylurea (NMU) and colchicine have long been used to develop new traits in crops, but these chemicals are carcinogenic and difficult to use (Sung et al 2013). Ionizing radiation can overcome the limitations of chemical treatment and generate new mutations over a short period of time (Lee et al 2015b).…”

“…Proton beams are composed of particles with a mass and electrical charge, and a lower LET than heavy ion beams (Lee et al 2015b). In this study, we irradiated soybean seeds of two elite Korean varieties with different doses of proton beams.…”

Impact of Proton Beam Irradiation on the Growth and Biochemical Indexes of Barley (Hordeum vulgare L.) Seedlings Grown under Salt Stress

“…Mutation breeding is an alternative method used to improve agronomic traits, such as stress resistance, physical parameters of grain, and nutritional value. It is known that ionizing radiation helps overcome the limitations of the chemical treatment so that new mutations can be generated in a short period [ 21 , 22 , 23 ]. There are two forms of ionizing radiation that transfer energy into a substance: non-particulate (gamma and X rays) and particulate (alpha and beta particles, neutrons, and protons).…”