10.9.2017: Roman A. VOLKOV (Chernivtsi, Ukraine): Hydrogen peroxide and regulation of stress response in Arabidopsis, HS 32.01, Institut für Pflanzenwissenschaften, Bereich Syst. Botanik und Geobotanik, Holteigasse 6, 17:00 Uhr.
Different forms of abiotic stress are accompanied by excessive production of hydrogen peroxide and other reactive oxygen species, resulting in oxidative damage of proteins and membrane lipids in the plant cell. Excessive generation of hydrogen peroxide during the early stage of heat stress response results not only in cellular damage but is also necessary for activation of HSF transcription factors and effective transcription of Hsp genes. Apx1 and Apx2 are heat-inducible HSF-dependent genes coding for cytosolic ascorbate peroxidases, which are involved in the control of hydrogen peroxide levels under heat stress. Apx2 is a heat shock gene, which is not expressed at normal temperature but strongly induced in meristematic tissues, guard cells and in hydathodes upon moderate heat stress. Rearrangements of the antioxidative system in catalase-deficient mutants of Arabidopsis result in a partial repression of heat-dependent transcription of Apx and sHsp genes.