title: Changes in DNA damage, molecular integrity, and copy number for plastid DNA and mitochondrial DNA during maize development.
abstract: The amount and structural integrity of organellar DNAs change during plant development, although the mechanisms of change are poorly understood. Using PCR-based methods, we quantified DNA damage, molecular integrity, and genome copy number for plastid and mitochondrial DNAs of maize seedlings. A DNA repair assay was also used to assess DNA impediments. During development, DNA damage increased and molecules with impediments that prevented amplification by Taq DNA polymerase increased, with light causing the greatest change. DNA copy number values depended on the assay method, with standard real-time quantitative PCR (qPCR) values exceeding those determined by long-PCR by 100- to 1000-fold. As the organelles develop, their DNAs may be damaged in oxidative environments created by photo-oxidative reactions and photosynthetic/respiratory electron transfer. Some molecules may be repaired, while molecules with unrepaired damage may be degraded to non-functional fragments measured by standard qPCR but not by long-PCR.
authors.affiliation: Department of Biology, University of Washington, Seattle, WA 98195-5325, USA.
authors.forename: Rachana A
authors.initials: RA
authors.lastname: Kumar
authors.affiliation: Department of Biology, University of Washington, Seattle, WA 98195-5325, USA.
authors.forename: Delene J
authors.initials: DJ
authors.lastname: Oldenburg
authors.affiliation: Department of Biology, University of Washington, Seattle, WA 98195-5325, USA bendich@uw.edu.
authors.forename: Arnold J
authors.initials: AJ
authors.lastname: Bendich
mesh_terms: D004249:DNA Damage / Q000235:genetics*; D004260:DNA Repair / Q000235:genetics / Q000528:radiation effects; D004272:DNA, Mitochondrial / Q000235:genetics*; D018744:DNA, Plant / Q000235:genetics*; D018628:Gene Dosage; D008027:Light; D008954:Models, Biological; D018087:Plastids / Q000235:genetics* / Q000528:radiation effects; D016133:Polymerase Chain Reaction; D036226:Seedlings / Q000235:genetics / Q000528:radiation effects; D003313:Zea mays / Q000235:genetics* / Q000254:growth & development* / Q000528:radiation effects
chemical_list: D004272:DNA, Mitochondrial; D018744:DNA, Plant
keywords: DNA damage; DNA repair; PCR; Zea mays.; organellar DNA; reactive oxygen species