title: Genome hypermethylation in Pinus silvestris of Chernobyl--a mechanism for radiation adaptation?
abstract: Adaptation is a complex process by which populations of organisms respond to long-term environmental stresses by permanent genetic change. Here we present data from the natural "open-field" radiation adaptation experiment after the Chernobyl accident and provide the first evidence of the involvement of epigenetic changes in adaptation of a eukaryote-Scots pine (Pinus silvestris), to chronic radiation exposure. We have evaluated global genome methylation of control and radiation-exposed pine trees using a method based on cleavage by a methylation-sensitive HpaII restriction endonuclease that leaves a 5' guanine overhang and subsequent single nucleotide extension with labeled [3H] dCTP. We have found that genomic DNA of exposed pine trees was considerably hypermethylated. Moreover, hypermethylation appeared to be dependent upon the radiation dose absorbed by the trees. Such hypermethylation may be viewed as a defense strategy of plants that prevents genome instability and reshuffling of the hereditary material, allowing survival in an extreme environment. Further studies are clearly needed to analyze in detail the involvement of DNA methylation and other epigenetic mechanisms in the complex process of radiation stress and adaptive response.
authors.affiliation: Department of Biological Sciences, University of Lethbridge, 4401 University Drive, Lethbridge, Alta, Canada T1K 3M4. olga.kovalchuk@uleth.ca
authors.forename: Olga
authors.initials: O
authors.lastname: Kovalchuk
authors.forename: Paula
authors.initials: P
authors.lastname: Burke
authors.forename: Andrey
authors.initials: A
authors.lastname: Arkhipov
authors.forename: Nikolaj
authors.initials: N
authors.lastname: Kuchma
authors.forename: S Jill
authors.initials: SJ
authors.lastname: James
authors.forename: Igor
authors.initials: I
authors.lastname: Kovalchuk
authors.forename: Igor
authors.initials: I
authors.lastname: Pogribny
mesh_terms: D000064:Acclimatization; D019175:DNA Methylation / Q000528:radiation effects*; D018744:DNA, Plant / Q000528:radiation effects; D018745:Genome, Plant; D028223:Pinus / Q000235:genetics* / Q000528:radiation effects*; D011836:Radiation Tolerance; D018788:Radioactive Hazard Release; D014455:Ukraine
chemical_list: D018744:DNA, Plant