HYDROGEN SULFIDE AS A REGULATORY MOLECULE IN PLANT CELLS

Abstract

For a long time, hydrogen sulfide has been known as strong toxin harmful to living organisms. Recent studies
have shown the beneficial effect of low doses of H2S on functioning of both animals and plants. It was also confirmed that H2S acts as a signaling molecule similar to two other well-known gasotransmitters, nitric oxide and carbon monoxide. The enzymes responsible for H2S generation have been identified in plant cells. These include desulfhydrases, located mainly in the cytosol, as well as sulfite reductase, present in chloroplasts, and mitochondrial ?-cyanoalanine synthase. Numerous studies indicated that H2S level increases significantly in plant tissues in response to unfavorable environmental conditions, such as salinity, heavy metals, drought, high and low temperature, suggesting its essential role in plant adaptation to abiotic stresses. I has been proposed that the main mechanism of H2S action is the post-translational modification of reactive cysteine residues in proteins, called S-sulfhydration.