Initial Yields of DNA Double-Strand Breaks and DNA Fragmentation Patterns Depend on Linear Energy Transfer in Tobacco BY-2 Protoplasts Irradiated with Helium, Carbon and Neon Ions

Yokota, Yuichiro; Yamada, Shinya; Hase, Yoshihiro; Shikazono, Naoya; Narumi, Issay; Tanaka, Atsushi; Inoue, Masayoshi

doi:10.1667/rr0701.1

Cited by 36 publications

(17 citation statements)

References 28 publications

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“…Here, irradiation of the higher-LET proton beam (1.461 keV· m ). This result is consistent with a previous report in that an increased DNA breakage yield in the higher-LET radiation treatment was detected, in comparison with helium ion beam (9.4 and 17.7 keV· m -1 ) and lower-LET carbon ion beam (94.8 and 124 keV· m -1 ) (Yokota et al, 2007). Comparing the lower-LET proton beam and gamma ray, treatment with the lower-LET proton beam resulted in a similar proportion of damaged and undamaged DNA to gamma ray, but generated a smaller portion of short DNA fragments which was represented by smaller tails in the comet-shaped DNA spots.…”

Section: Discussionsupporting

confidence: 93%

“…Comparing the lower-LET proton beam and gamma ray, treatment with the lower-LET proton beam resulted in a similar proportion of damaged and undamaged DNA to gamma ray, but generated a smaller portion of short DNA fragments which was represented by smaller tails in the comet-shaped DNA spots. Yokota et al (2007) reported that the proportion of short DNA fragments was larger in treatments with high-LET heavy ion beam such as carbon and neon beam than with gamma ray, implying that higher-LET radiation may result in more closely spaced double-strand breaks in the DNA, and thus might result in severe chromosomal aberrations. In their research, helium ion beam, which show comparatively low-LET, caused similar DNA fragmentation patterns to gamma ray.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, lower-LET proton beam may induce DNA breaks more randomly in terms of localization of breaks than gamma ray and other ion beam that have been studied. The reason for this is mostly unknown, although DNA fragmentation patterns have been shown to be dependent on the ion type of the radiation even when the LET is similar (Yokota et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

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

Lee

et al. 2015

Hortic. Environ. Biotechnol.

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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.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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

Lee

et al. 2015

Hortic. Environ. Biotechnol.

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“…A high yield of DSBs after heavy-ion beam irradiation was revealed by experiments on both animal and plant cells [19,20]. Therefore, significant DNA damage is likely to be caused by heavy-ion irradiation, although sequencing analysis of heavy-ion-induced DNA alterations is limited.…”

Section: Introductionmentioning

confidence: 99%

Characterization of highly efficient heavy-ion mutagenesis in Arabidopsis thaliana

et al. 2011

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BackgroundHeavy-ion mutagenesis is recognised as a powerful technology to generate new mutants, especially in higher plants. Heavy-ion beams show high linear energy transfer (LET) and thus more effectively induce DNA double-strand breaks than other mutagenic techniques. Previously, we determined the most effective heavy-ion LET (LETmax: 30.0 keV μm-1) for Arabidopsis mutagenesis by analysing the effect of LET on mutation induction. However, the molecular structure of mutated DNA induced by heavy ions with LETmax remains unclear. Knowledge of the structure of mutated DNA will contribute to the effective exploitation of heavy-ion beam mutagenesis.ResultsDry Arabidopsis thaliana seeds were irradiated with carbon (C) ions with LETmax at a dose of 400 Gy and with LET of 22.5 keV μm-1 at doses of 250 Gy or 450 Gy. The effects on mutation frequency and alteration of DNA structure were compared. To characterise the structure of mutated DNA, we screened the well-characterised mutants elongated hypocotyls (hy) and glabrous (gl) and identified mutated DNA among the resulting mutants by high-resolution melting curve, PCR and sequencing analyses. The mutation frequency induced by C ions with LETmax was two-fold higher than that with 22.5 keV μm-1 and similar to the mutation frequency previously induced by ethyl methane sulfonate. We identified the structure of 22 mutated DNAs. Over 80% of the mutations caused by C ions with both LETs were base substitutions or deletions/insertions of less than 100 bp. The other mutations involved large rearrangements.ConclusionsThe C ions with LETmax showed high mutation efficiency and predominantly induced base substitutions or small deletions/insertions, most of which were null mutations. These small alterations can be determined by single-nucleotide polymorphism (SNP) detection systems. Therefore, C ions with LETmax might be useful as a highly efficient reverse genetic system in conjunction with SNP detection systems, and will be beneficial for forward genetics and plant breeding.

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“…22) Initial DSB yields depended on LET and highest RBE was obtained at 124 and 241 keV/μm with carbon ions. It was also observed that ion beams yielded short DNA fragments of several hundred kbp more frequently than gammarays.…”

Section: Relative Biological Effectivenessmentioning

confidence: 94%

Studies on Biological Effects of Ion Beams on Lethality, Molecular Nature of Mutation, Mutation Rate, and Spectrum of Mutation Phenotype for Mutation Breeding in Higher Plants

Tanaka

Shikazono

Hase

2010

JRR

Self Cite

237

145

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Recently, heavy ions or ion beams have been used to generate new mutants or varieties, especially in higher plants. It has been found that ion beams show high relative biological effectiveness (RBE) of growth inhibition, lethality, and so on, but the characteristics of ion beams on mutation have not been clearly elucidated. To understand the effect of ion beams on mutation induction, mutation rates were investigated using visible known Arabidopsis mutant phenotypes, indicating that mutation frequencies induced by carbon ions were 20-fold higher than by electrons. In chrysanthemum and carnation, flower-color and flower-form mutants, which are hardly produced by gamma rays or X rays, were induced by ion beams. Novel mutants and their responsible genes, such as UV-B resistant, serrated petals and sepals, anthocyaninless, etc. were induced by ion beams. These results indicated that the characteristics of ion beams for mutation induction are high mutation frequency and broad mutation spectrum and therefore, efficient induction of novel mutants. On the other hand, PCR and sequencing analyses showed that half of all mutants induced by ion beams possessed large DNA alterations, while the rest had point-like mutations. Both mutations induced by ion beams had a common feature that deletion of several bases were predominantly induced. It is plausible that ion beams induce a limited amount of large and irreparable DNA damage, resulting in production of a null mutation that shows a new mutant phenotype.

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Initial Yields of DNA Double-Strand Breaks and DNA Fragmentation Patterns Depend on Linear Energy Transfer in Tobacco BY-2 Protoplasts Irradiated with Helium, Carbon and Neon Ions

Cited by 36 publications

References 28 publications

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

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

Characterization of highly efficient heavy-ion mutagenesis in Arabidopsis thaliana

Studies on Biological Effects of Ion Beams on Lethality, Molecular Nature of Mutation, Mutation Rate, and Spectrum of Mutation Phenotype for Mutation Breeding in Higher Plants

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