ORIGINAL ARTICLE

The Influence of Hydrogen Peroxide on the Content of Prohibitines Phb3 and Phb4 in the Leaves of Arabidopsis thaliana

According to modern ideas, plant mitochondria regulate the expression of nuclear genes and act as signalling organelles providing the tolerance of plants to external stressors. Highly conservative membrane proteins prohibitines (Phb) responsible for membrane-peptide interactions in organelles of animals, plants and microorganisms accumulate in mitochondria and modulate the state of their membranes, participating in the regulation of mitochondrial-mediated signalling. The tuning of the content of the Phb is poorly investigated for today day. Most of biotic and abiotic stresses are associated with production of reactive oxygen species (ROS) which can play as signalling role as well as cause damage. Hydrogen peroxide is one of the forms of ROS. The goal of this research was to study the effect of different doses of hydrogen peroxide on the Phb3 and Phb4 content in Arabidopsis plants. In the leaves of Arabidopsis thaliana heat shock (HS, 42°C, 3 h) caused the increasing of the content of Phb after 24 h from the stop of the influence and the increasing of superoxide radical content immediately after HS. So the increasing of the content of Phb and ROS as a result of HS occurs simultaneously. Next we investigated the influence of oxidative stress on Phb content. It was shown at first that H2O2 decreases the content of Phb in dose-depend manner at the starting hours of the action (2 to 40 mM H₂O₂ during 1 to 2 h were used). At the continuation of the influence till 24 h the content of Phb returns to the control value. Herewith the suppressing effect is demonstrated by non-stress doses of H2O2 (2 to 10 mM). The stress dose of H2O2 (40 mM at 24 h) doesn’t effect on the content of Phb, but causes the increasing of the content of Hsp 17.7 and wilting of the leaves which indicates the stressed condition of the plants. The results received speak in favor that at the protein level the increasing of Phb3 and Phb4 content is not activated by ROS-mediated system even during the development of the oxidative stress.