The responses of L-gulonolactone oxidase and HKT2;1 genes inAeluropus littoralis’ shoots under high concentration of sodium chloride

Salinity is one of the most important abiotic stresses that limit crop growth and production. Salt stressinfluences plants in two ways: by affecting ion toxicity and increasing osmotic stress. Ion homeostasis, the excretion ofNa+ and using antioxidant systems are the major strategies of salt tolerance in plants. Na+ and K+ transporters withenzymes that are involved in detoxification of reactive oxygen species play key roles in salt tolerance in plants. The aimof this study was to investigate the responses of high affinity K+ transporter2;1 gene (HKT2;1) which is involved inregulation of ion homeostasis and L-gulonolactone oxidase (GLOase) which is involved in the ascorbic acid biosynthesispathway, under different concentrations of NaCl over different time points in Aeluropus littoralis shoots. Results fromReal Time PCR data showed that expressions of both genes were influenced by external and internal concentrations ofNa+ and the internal K+ content. AlHKT2;1 was significantly upregulated by increasing Na+ concentration at all timepoints. Furthermore, its highest expression level in shoots occurred after 6 days in 300mM NaCl in shoots which was25folds more than untreated shoots. AlGLOase expression levels increased 54 h after initiation of salt stress. These resultsindicate that AlHKT2;1 and AlGLOase respond to different salinity conditions and probably are part of the mechanismsinvolved in tolerance to high salt concentrations in A. littoralis.

Keywords:

Aeluropus littoralis , Ascorbic Acid , Gene Expression , HKT Genes , Salt Stress