Chlorine ions but not sodium ions alter genome stability of Arabidopsis thaliana.
Various environmental stresses influence plant genome stability. Most of these stresses, such as ionizing radiation, heavy metals and organic chemicals, represent potent DNA-damaging agents. Here, we show that exposure to NaCl, the stress that is not thought to cause direct DNA damage, results in an increase in the level of strand breaks and homologous recombination rates (RRs) in Arabidopsis thaliana plants. The effect of salt stress on the RR was found to be primarily associated with Cl(-) ions, since exposure of plants to Na(2)SO(4) did not increase the RR, whereas exposure to MgCl(2) resulted in an increase. Changes in the number of strand breaks and in the RR were also paralleled by transcriptional activation of AtRad51 and down-regulation of AtKu70. The progeny of exposed plants exhibited higher RRs, higher expression of AtRad51, lower expression of AtKu70, higher tolerance to salt and methyl methane sulfate (MMS) stresses, as well as a higher increase in RR upon further exposure to stress. Our experiments showed that NaCl is a genotoxic stress that leads to somatic and transgenerational changes in recombination rates, and these changes are primarily triggered by exposure to Cl(-) ions.
Boyko
Alex
A
Department of Biological Sciences, 4401 University Drive, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada.
Golubov
Andrey
A
Bilichak
Andriy
A
Kovalchuk
Igor
I
D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000378:metabolism; D002712:Chlorides / Q000494:pharmacology*; D004249:DNA Damage; D018744:DNA, Plant / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D042822:Genomic Instability; D015636:Magnesium Chloride / Q000494:pharmacology; D018749:RNA, Plant / Q000235:genetics; D051135:Rad51 Recombinase / Q000378:metabolism; D011995:Recombination, Genetic; D012964:Sodium / Q000494:pharmacology*; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological; D013431:Sulfates / Q000494:pharmacology; D015533:Transcriptional Activation
D029681:Arabidopsis Proteins; D002712:Chlorides; D018744:DNA, Plant; D004268:DNA-Binding Proteins; C463462:KU70 protein, Arabidopsis; D018749:RNA, Plant; D013431:Sulfates; D015636:Magnesium Chloride; C012036:sodium sulfate; D012965:Sodium Chloride; D012964:Sodium; C495146:ATRAD51 protein, Arabidopsis; D051135:Rad51 Recombinase