Global climate change is identified as a major threat to the survival of natural ecosystems. The variations in global climate have gained the attention of researchers worldwide, as these changes negatively affect agriculture by reducing crop productivity and food security.  Projects related to abiotic stress tolerance are significant because they address important challenges facing agriculture and food security, contribute to more sustainable agricultural practices, and advance our understanding of fundamental plant biology. Some plants have defense mechanisms that are activated upon receiving stress stimuli to increase systemic tolerance to abiotic stresses such as heat, light, and cold. Salicylic acid-binding protein 2 (SABP2) from tobacco exhibits a high affinity for salicylic acid (SA) and is an important component in the SA-signaling pathway. SABP2 interacts with other cellular proteins to initiate downstream signaling and activate responses leading to resistance. Several SABP2-interacting proteins (SIP), including SIP-428, have been identified. The main goal of this proposed research is to determine the role of SIP-428 in mediating environmental stresses. SIP-428 is a SIR2-type non-histone deacetylase enzyme. De/acetylation is a common post-translational modification of proteins in eukaryotes. Since SIP-428 is a SABP2-interacting protein, it is involved in plant immune signaling. To determine the role of SIP-428 in plant physiology, it was biochemically characterized, and transgenic tobacco plants silenced in SIP-428 expression were previously generated and analyzed. Transgenic tobacco plants overexpressing SIP-428 were also generated. These lines expressed SIP428 at higher levels upon treatment with estradiol. Transgenic tobacco that overexpresses SIP-428 has been used in this study. To test the role of SIP428 in abiotic stress, the transgenic plants will be treated with abiotic stress-inducing chemicals, e.g. NaCl (salinity stress), mannitol (osmotic stress), and PEG6000 (drought stress). The treated seedlings will be allowed to grow for a specific time (1-2 weeks). The expression of SIP-428 will be monitored by western blotting (using anti-myc antibodies). The effects of SIP-428 expression on abiotic stress tolerance will be investigated biochemically by examining the activities of antioxidant enzymes, catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX). Additionally, gene expression analysis will also be conducted to determine the expression of antioxidant genes.