1. A plant cell transformed with an exogenous nucleic acid said exogenous nucleic acid comprising a heterologous promoter operably linked to a nucleotide sequence encoding a polypeptide wherein said polypeptide has 95 percent or greater sequence identity to the amino acid sequence of SEQ ID NO: 44, and wherein overexpression of said polypeptide in a transformed plant grown from said transformed plant cell results in an increased level of tolerance to salinity or oxidative stress as compared to the corresponding level in tolerance to salinity or oxidative stress of a control plant of the same species cultivated under the same conditions that does not comprise said exogenous nucleic acid.