title: Increase in recombination rate in Arabidopsis thaliana plants sharing gaseous environment with X-ray and UVC-irradiated plants depends on production of radicals.
abstract: X-ray and UVC are the two physical agents that damage DNA directly, with both agents capable of inducing double-strand breaks. Some of our recent work has demonstrated that local exposure to UVC results in a systemic increase in recombination frequency, suggesting that information about exposure can be passed from damaged to non-damaged tissue. Indeed, we recently showed that plants sharing the same enclosed environment with UVC-irradiated plants exhibit similar increase in homologous recombination frequency as irradiated plants. Here, we further tested whether yet another DNA-damaging agent, X-ray, is capable of increasing recombination rate (RR) in neighboring plants grown in a Petri dish. To test this, we grew plants exposed to X-ray or UVC irradiation in an enclosed environment next to non-exposed plants. We found that both X-ray and UVC-irradiated plants and neighboring plants exhibited comparable increases in the levels of strand breaks and the RR. We further showed that pre-exposure of plants to radical scavenger DMSO substantially alleviates the radiation-induced increase in RR and prevents formation of bystander signal. Our results suggest that the increase in RR in bystander plants can also be triggered by X-ray and that radicals may play some role in initiation or maintenance of this signal.
authors: Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada.
authors: Franz J
authors: FJ
authors: Zemp
authors: Corinne
authors: C
authors: Sidler
authors: Igor
authors: I
authors: Kovalchuk
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects*; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects / Q000528:radiation effects; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004777:Environment; D005609:Free Radicals / Q000378:metabolism*; D005740:Gases / Q000378:metabolism*; D018745:Genome, Plant / Q000235:genetics; D042822:Genomic Instability / Q000187:drug effects / Q000528:radiation effects; D059765:Homologous Recombination / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D011995:Recombination, Genetic / Q000187:drug effects / Q000528:radiation effects*; D014466:Ultraviolet Rays; D014965:X-Rays
chemical_list: D005609:Free Radicals; D005740:Gases; D004121:Dimethyl Sulfoxide