title: Increase of homologous recombination frequency in vascular tissue of Arabidopsis plants exposed to salt stress.
abstract: Here we analyzed the influence of salt stress on plant genome stability. Homologous recombination events were detected in transgenic Arabidopsis plants that carried in their genome a beta-glucuronidase recombination marker. Recombination events were scored as blue sectors using a stereo microscope. Exposure to 50 mM salt resulted in a 3.0-fold increase in recombination frequency. To analyze the organ and tissue specificity of recombination events, we examined cross-sections of leaves, stems and roots. We found that nearly 30% of recombination events in plants grown under normal conditions and nearly 50% of events in plants grown on salt were undetected by the conventional method. Most of the recombination events represented a cluster/group of cells (12 on average), although events with single cells were also detected. Recombination events were very frequent in leaf mesophyll cells. On average, individual recombination events located on leaves contained more cells than events located on roots or stems. Analysis of recombination events in cross-sectioned tissue of salt-treated plants revealed a shift in the distribution of recombination events towards the vascular tissue. We discuss the significance of the finding for plant stress physiology.
authors.affiliation: Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada.
authors.forename: Alex
authors.initials: A
authors.lastname: Boyko
authors.forename: Darryl
authors.initials: D
authors.lastname: Hudson
authors.forename: Prasanna
authors.initials: P
authors.lastname: Bhomkar
authors.forename: Palak
authors.initials: P
authors.lastname: Kathiria
authors.forename: Igor
authors.initials: I
authors.lastname: Kovalchuk
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics* / Q000502:physiology; D019457:Chromosome Breakage / Q000235:genetics; D018744:DNA, Plant / Q000032:analysis / Q000235:genetics; D005787:Gene Frequency; D005819:Genetic Markers / Q000235:genetics; D042822:Genomic Instability / Q000187:drug effects / Q000235:genetics; D005966:Glucuronidase / Q000032:analysis / Q000235:genetics; D018515:Plant Leaves / Q000737:chemistry / Q000166:cytology / Q000187:drug effects / Q000235:genetics; D018517:Plant Roots / Q000737:chemistry / Q000166:cytology / Q000187:drug effects / Q000235:genetics; D018547:Plant Stems / Q000737:chemistry / Q000166:cytology / Q000187:drug effects / Q000235:genetics; D030821:Plants, Genetically Modified; D011995:Recombination, Genetic / Q000187:drug effects*; D012689:Sequence Homology, Nucleic Acid; D012965:Sodium Chloride / Q000494:pharmacology*
chemical_list: D018744:DNA, Plant; D005819:Genetic Markers; D012965:Sodium Chloride; D005966:Glucuronidase