Effect of Heat Hardening on Expression of Genes phb3 and phb4 and Accumulation of Phb Proteins in Green Leaves of Arabidopsis thaliana

In the organelles of animals, plants, and microorganisms, highly conserved membrane proteins prohibitins (Phb) govern some of the protein-membrane interactions. Changes in expression of genes phb3 and phb4 in arabidopsis induce the genes that are also activated by oxidative, salt, and other abiotic stresses. Prohibitins are assumed to participate in the modulation of the state of mitochondrial membranes that are an important element of stress response. Thus, prohibitins may influence the development of response to stress. However, the data directly indicating a relationship between plant prohibitins and adaptation to stress are not available. It was shown that preliminary hardening of arabidopsis plants at 45 degrees C protected leaves under a severe heat shock (50 degrees C). After exposure to different hardening temperatures, the content of proteins Phb3 and Phb4 in the leaves of arabidopsis reliably increased several hours after the termination of stress, and we observed a considerable rise in the content of phb3 and phb4 transcripts and accumulation of proteins Phb3 and Phb4 in the mitochondria right after the treatment at a temperature of 45 degrees C. Possible reasons for this accumulation are discussed.