Study of Hydrogen Cyanide Effects on Salt Stress Induction in Aeluropus littoralis

Salt stress is a serious problem for plant growth and development. To analyze salt stress resistance and physiological behavior of plants, the halophyte Aeluropus littoralis was studied. Salt stress augments ethylene hormone production in plant tissue and this leads to increased hydrogen cyanide levels. In the other hand, there is a cyanide purge mechanism involving three enzymes: Cyanase, Rhodanese and βcyanoalanine synthase. To study plant cell growth and development under salt stress conditions, an analysis of differential expression of genes involved in biosynthesis and purge of cyanide is needed. In this study, Aeluropus littoralis cell suspensions were subjected to different concentrations of salt and potassium cyanide in the medium. Factorial analysis of NaCl and KCN in 0, 0/0.2, 0/0.4, 60/0, 60/0.2, 60/0.4, 120/0, 120/0.2 and 120/0.4 mM concentrations were assessed. Our study demonstrated that KCN treatment significantly reduced production of dry material. The results showed that, although cyanide has negative effect on cell growth, the cyanide detoxification gene network was not activated in these conditions. In addition, the interaction between cyanide and salinity indicated that salt stress in the presence of 0.4 mM KCN increases cell growth by 40 percent because expression of the CAS gene was reduced enormously. An increase of salinity in the presence of 0.2 mM KCN, however, reduced expression of ACO, a key gene in HCN and ethylene production. As intracellular level of HCN declined, cell growth rose. Thus external treatment of cyanide increases plant dry material and plant resistance in salt stress conditions.