Acute exposure to UVB has a more profound effect on plant genome stability than chronic exposure.
Environmental factors that damage DNA have various lengths of exposure and intensity levels. Although the results of increasing the intensity of a DNA damaging agent is often predictable, it is not clear whether the stage during development when the exposure is received has any influence on the amount of DNA damage. In this paper we analyzed the influence of UVB on the stability of Arabidopsis thaliana and the Nicotiana tabacum genomes. Our experiments showed that the acute exposure to UVB produces a significantly greater increase in homologous recombination frequency (HRF) and recombination rate (RR) compared with that produced by chronic exposure. The increase in HRF showed a positive correlation with UVB dose and a negative correlation with plant age. In other words, as the UVB dose was increased, there was a concomitant increase in HRF. Conversely, older plants had a lower HRF increase as compared to younger plants. Our experiments suggest that exposure to UVB makes the most significant impact on genome stability during the early stages of plant development.
Boyko
Alex
A
Department of Biological Sciences, University of Lethbridge, Lethbridge, Alta. T1K 3M4, Canada.
Greer
Michael
M
Kovalchuk
Igor
I
D017360:Arabidopsis / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects; D018745:Genome, Plant / Q000528:radiation effects*; D042822:Genomic Instability / Q000528:radiation effects*; D010641:Phenotype; D030821:Plants, Genetically Modified / Q000254:growth & development / Q000528:radiation effects; D011995:Recombination, Genetic / Q000528:radiation effects; D014026:Nicotiana / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects; D014466:Ultraviolet Rays