In the present work, Petunia 9 hybrida leaf
discs maintained on regeneration medium for 8 days were
used to assess the effects of genotoxic stress induced by
in vitro culture. The investigation was carried out by
comparing the response of intact leaves excised from
Petunia 9 hybrida plantlets grown in vitro and the
regenerating leaf discs. In situ detection by histochemical
staining and alkaline-Single Cell Gel Electrophoresis
(SCGE) analysis demonstrated that both reactive oxygen
species accumulation and DNA damage were enhanced in
explants cultured in vitro. Significant up-regulation of the
PhOGG1 (8-oxoguanine DNA glycosylase/lyase), PhAPX
(ascorbate peroxidase) and PhMT2 (metallothionein) genes
involved in ... More
In the present work, Petunia 9 hybrida leaf
discs maintained on regeneration medium for 8 days were
used to assess the effects of genotoxic stress induced by
in vitro culture. The investigation was carried out by
comparing the response of intact leaves excised from
Petunia 9 hybrida plantlets grown in vitro and the
regenerating leaf discs. In situ detection by histochemical
staining and alkaline-Single Cell Gel Electrophoresis
(SCGE) analysis demonstrated that both reactive oxygen
species accumulation and DNA damage were enhanced in
explants cultured in vitro. Significant up-regulation of the
PhOGG1 (8-oxoguanine DNA glycosylase/lyase), PhAPX
(ascorbate peroxidase) and PhMT2 (metallothionein) genes
involved in DNA repair and antioxidant defence was
observed in the explants cultured in vitro, compared to
intact leaves. The Petunia 9 hybrida leaf discs were
exposed to increasing (0, 100, 150, 200 and 400 mM)
doses of the model genotoxic agent hydrogen peroxide
(H2O2) and then analysed. The DNA diffusion assay
highlighted the dose- and time-dependent fluctuations of
programmed cell death/necrosis events in response to
H2O2. Leaf discs treated with increasing H2O2 concentration
and untreated controls were analysed by FPG-SCGE to
assess the level of oxidative DNA damage at different time
points following treatments. The PhOGG1, PhAPX and
PhMT2 genes were significantly up-regulated in response
to H2O2, reaching the highest transcript levels with the
150 mM dose. Based on the reported data, these genes
might be used as molecular indicators of the genotoxic
stress response in Petunia 9 hybrida cells.
