Arabidopsis nucleoside diphosphate kinase 2 (AtNDPK2) is an upstream signaling molecule that has been shown to induce stress tolerance in plants. In this study, the AtNDPK2 gene, under the control of a stress-inducible SWPA2 promoter, was introduced into the genome of tall fescue (Festuca arundinacea Schreb.) plants. The induction of the transgene expression mediated by methyl viologen (MV) and NaCl treatments were confirmed by RT-PCR and northern blot analysis, respectively. Under salt stress treatment, the transgenic tall fescue plants (SN) exhibited lower level of H2O2 and lipid peroxidation accumulations than the non-transgenic (NT) plants. The transgenic tall fescue plants also showed higher level of NDPK enzyme activity compared to NT plants. The SN plants were survived at 300 mM NaCl treatment, whereas the NT plants were severely affected. These results indicate that stress-inducible overexpression of AtNDPK2 might efficiently confer the salt stress tolerance in tall fescue plants.

Environmental stress is a growing problem for the productivity of forage crops. Reactive oxygen species (ROS) formation due to several abiotic stresses is a fundamental process that interrupts several physiological processes and causes a significant reduction on growth and yield of many forage crops. Molecular breeding such as genetic transformation has become a popular biotechnological tool for improving forage quality as well as improves tolerance to various abiotic stresses. As a first step of genetic transformation in tall fescue, we established an efficient Agrobacterium-mediated genetic transformation protocol using mature seed-derived embryogenic callus. After optimization of the transformation system, several genes of interest have been used to generate abiotic stress tolerant forage grasses. We generated transgenic tall fescue plants expressing NDPK genes under the control of the oxidative stress-inducible SWPA2 promoter. Transgenic plants showed enhanced tolerance to several abiotic stresses. Results in the current study, suggest that NDPK mediated multiple stress tolerance by increasing the expression of genes involved in antioxidant and protective functions, possibly through activation of an MAPK cascade.