Transgenerational stress memory in Arabidopsis thaliana (L.) Heynh.: antioxidative enzymes and HSP70

Transgenerational transmission of information about stress exposure is manifested as an increase in the somatic homologous recombination frequency in plants. Our aim was to investigate whether information about changes of antioxidative enzyme activities and protein HSP70 induction are also transmitted in response to stress caused by UV-C irradiation. These stress indicators were investigated in Arabidopsis thaliana plants exposed to UV-C irradiation (6 and 600 J m(-2)) and its non-irradiated progeny. The activity of catalase was significantly decreased in the irradiated plants in comparison to the non-irradiated control plants, while the activity of guaiacol peroxidase was increased. The ascorbate peroxidase activity was not significantly changed. In irradiated plants there was an induction of a new HSP70 protein isoform. In the non-irradiated progeny of irradiated plants, a significant decrease in catalase and ascorbate peroxidase activity was noticed in comparison to plants whose parents were not irradiated. There was no significant change in guaiacol peroxidase activity or induction of HSP70 isoforms in the progeny. The obtained results indicate that, besides the already known increase in frequency of somatic homologous recombination, transmission of information about stress exposure can also include changes in activities of antioxidative enzymes catalase and ascorbate peroxidase. The explanations for the observed changes and the mechanism by which they occur have to be established in further research.