title: γ irradiation with different dose rates induces different DNA damage responses in Petunia x hybrida cells.
abstract: In plants, there is evidence that different dose rate exposures to gamma (γ) rays can cause different biological effects. The dynamics of DNA damage accumulation and molecular mechanisms that regulate recovery from radiation injury as a function of dose rate are poorly explored. To highlight dose-rate dependent differences in DNA damage, single cell gel electrophoresis was carried out on regenerating Petunia x hybrida leaf discs exposed to LDR (total dose 50 Gy, delivered at 0.33 Gy min(-1)) and HDR (total doses 50 and 100 Gy, delivered at 5.15 Gy min(-1)) γ-ray in the 0-24h time period after treatments. Significant fluctuations of double strand breaks and different repair capacities were observed between treatments in the 0-4h time period following irradiation. Dose-rate-dependent changes in the expression of the PhMT2 and PhAPX genes encoding a type 2 metallothionein and the cytosolic isoform of ascorbate peroxidase, respectively, were detected by Quantitative RealTime-Polymerase Chain Reaction. The PhMT2 and PhAPX genes were significantly up-regulated (3.0- and 0.7-fold) in response to HDR. The results are discussed in light of the potential practical applications of LDR-based treatments in mutation breeding.
authors: Dipartimento di Biologia e Biotecnologie L. Spallanzani, via Ferrata 9, 27100 Pavia, Italy.
authors: Mattia
authors: M
authors: Donà
authors: Lorenzo
authors: L
authors: Ventura
authors: Anca
authors: A
authors: Macovei
authors: Massimo
authors: M
authors: Confalonieri
authors: Monica
authors: M
authors: Savio
authors: Annalisa
authors: A
authors: Giovannini
authors: Daniela
authors: D
authors: Carbonera
authors: Alma
authors: A
authors: Balestrazzi
mesh_terms: D060387:Ascorbate Peroxidases / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage / Q000528:radiation effects*; D004260:DNA Repair / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D005838:Genotype; D008668:Metallothionein / Q000235:genetics / Q000378:metabolism; D032306:Petunia / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D011829:Radiation Dosage; D017382:Reactive Oxygen Species / Q000378:metabolism; D012038:Regeneration / Q000528:radiation effects
chemical_list: D017382:Reactive Oxygen Species; D008668:Metallothionein; D060387:Ascorbate Peroxidases