Gamma irradiation with different dose rates induces different DNA damage responses in Petunia x hybrida cells

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• 作者：Mattia Donà ; ^a ; Lorenzo Ventura^b ; Anca Macovei^a ; Massimo Confalonieri^c ; Monica Savio^d ; Annalisa Giovannini^e ; Daniela Carbonera^a ; Alma Balestrazzi^a ; ^{alma.balestrazzi@unipv.it}
• 关键词：APX ; ascorbate peroxidase ; DAB ; 3-3&prime ; -diaminobenzidine ; DAPI ; 4&prime ; 6-diamino-2-phenylindole ; DSB ; double strand break ; HDR ; high dose rate ; IR ; ionizing radiation ; LDR ; low dose rate ; MT ; metallothionein ; 8-oxo-dG ; 7&prime ; 8-dihydro-8-oxoguanine
• 刊名：Journal of Plant Physiology
• 出版年：2013
• 出版时间：15 May, 2013
• 年：2013
• 卷：170
• 期：8
• 页码：780-787
• 全文大小：798 K

文摘

In plants, there is evidence that different dose rate exposures to gamma (¦Ã) 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) ¦Ã-ray in the 0-24 h time period after treatments. Significant fluctuations of double strand breaks and different repair capacities were observed between treatments in the 0-4 h 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.