This invention describes the identification of pre-messenger RNA processing as a novel target of environmental stress caused by example of lithium and sodium toxicity. Overexpression of different types of proteins (or protein fragments) from different organisms but all involved in pre-mRNA processing, protects yeast from salt stress, which indicates that any stimulation of this process, independently of its mechanism, may counteract the toxic effects of mineral salts. A similar phenotype of tolerance to NaCl and to LiCl has been observed by overexpression of these types of proteins in transgenic Arabidopsis plants, demonstrating the generality of this protective effect in eukaryotic cells and organisms.