title: Genome-wide analysis of mutations in mutant lineages selected following fast-neutron irradiation mutagenesis of Arabidopsis thaliana.
abstract: Ionizing radiation has long been known to induce heritable mutagenic change in DNA sequence. However, the genome-wide 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.
authors.affiliation: Department of Plant Sciences, University of Oxford, Oxford, United Kingdom;
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Belfield
authors.forename: Xiangchao
authors.initials: X
authors.lastname: Gan
authors.forename: Aziz
authors.initials: A
authors.lastname: Mithani
authors.forename: Carly
authors.initials: C
authors.lastname: Brown
authors.forename: Caifu
authors.initials: C
authors.lastname: Jiang
authors.forename: Keara
authors.initials: K
authors.lastname: Franklin
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Alvey
authors.forename: Anjar
authors.initials: A
authors.lastname: Wibowo
authors.forename: Marko
authors.initials: M
authors.lastname: Jung
authors.forename: Kit
authors.initials: K
authors.lastname: Bailey
authors.forename: Sharan
authors.initials: S
authors.lastname: Kalwani
authors.forename: Jiannis
authors.initials: J
authors.lastname: Ragoussis
authors.forename: Richard
authors.initials: R
authors.lastname: Mott
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Harberd
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000528:radiation effects*; D002869:Chromosome Aberrations; D032461:Chromosomes, Plant / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D004252:DNA Mutational Analysis / Q000379:methods; D004261:DNA Replication; D018744:DNA, Plant / Q000235:genetics* / Q000378:metabolism; D005214:Fast Neutrons; D018745:Genome, Plant; D054643:INDEL Mutation; D010641:Phenotype; D017354:Point Mutation; D011742:Pyrimidine Nucleotides / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion
chemical_list: D018744:DNA, Plant; D011742:Pyrimidine Nucleotides