Radiation Response of Soaked Barley Seeds

Kamra, Om P.; Kamra, Saroja K.; Nilan, R.A.; Konzak, C. F.

doi:10.1111/j.1601-5223.1960.tb03081.x

Cited by 10 publications

(1 citation statement)

References 29 publications

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“…2; Table 1). These differences are significant (G-test, P = 1.7 3 10 À4 ) and may reflect heterogeneity in radiation dosage or in water content of irradiated seeds (seed radiosensitivity is dependent on water content) (Kamra et al 1960). FN exposure increases both overall mutation frequency and the frequency of specific molecular mutation classes.…”

Section: Chromosomal Distribution and Frequencies Of Fn-induced Mutatmentioning

confidence: 95%

Genome-wide analysis of mutations in mutant lineages selected following fast-neutron irradiation mutagenesis of Arabidopsis thaliana

Belfield

Gan²,

Mithani³

et al. 2012

Genome Res.

127

175

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Ionizing radiation has long been known to induce heritable mutagenic change in DNA sequence. However, the genomewide effect of radiation is not well understood. Here we report the molecular properties and frequency of mutations in phenotypically selected mutant lines isolated following exposure of the genetic model flowering plant Arabidopsis thaliana to fast neutrons (FNs). Previous studies suggested that FNs predominantly induce deletions longer than a kilobase in A. thaliana. However, we found a higher frequency of single base substitution than deletion mutations. While the overall frequency and molecular spectrum of fast-neutron (FN)-induced single base substitutions differed substantially from those of ''background'' mutations arising spontaneously in laboratory-grown plants, G:C >A:T transitions were favored in both. We found that FN-induced G:C>A:T transitions were concentrated at pyrimidine dinucleotide sites, suggesting that FNs promote the formation of mutational covalent linkages between adjacent pyrimidine residues. In addition, we found that FNs induced more single base than large deletions, and that these single base deletions were possibly caused by replication slippage. Our observations provide an initial picture of the genome-wide molecular profile of mutations induced in A. thaliana by FN irradiation and are particularly informative of the nature and extent of genome-wide mutation in lines selected on the basis of mutant phenotypes from FN-mutagenized A. thaliana populations.[Supplemental material is available for this article.]Ionizing radiation is pervasive in the environment and acts as a natural mutagen via its DNA-damaging properties (Friedberg et al. 2006). In addition, the mutagenic property of artificial ionizing radiation has been a mainstay of genetic research since the pioneering experiments of Müller (1928). However, while the effects of ionizing radiation on individual genes are now relatively well understood, its genome-wide effects are not. We therefore undertook an analysis of the genome-wide consequences of fast neutron (FN) irradiation in Arabidopsis thaliana, comparing our findings with those of recent studies documenting the frequency and molecular spectrum of spontaneous ''background'' mutations in the genomes of laboratory-grown ''mutation accumulation'' (MA) line Arabidopsis plants (Ossowski et al. 2010) and of Arabidopsis plants regenerated in vitro from root tissue explants (Jiang et al. 2011). We found that exposure of Arabidopsis to FNs induces a broader range of mutational lesions than previously suspected, and that both the incidence and spectrum of FN-induced mutations are distinct from those of ''spontaneous'' mutations. These discoveries have important consequences for the use of FNs in experimental plant mutagenesis and provide an indication of the likely mutagenic effects of environmental ionizing radiation on organisms living in the wild (Hinton et al. 2007). Results FN irradiation, mutant generation, and isolationOur analyses began with a multiply mutant Arab...

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Section: Chromosomal Distribution and Frequencies Of Fn-induced Mutatmentioning

confidence: 95%