Expression of Arabidopsis SR‐like splicing proteins confers salt tolerance to yeast and transgenic plants

Abstract

SummarySearching for novel targets of salt toxicity in eukaryotic cells, we have screened an Arabidopsis thaliana cDNA library to isolate genes conferring increased tolerance to salt stress when expressed in the yeast Saccharomyces cerevisiae. Here we show that expression of the`alternating arginine-rich' (or RS) domains of two different SR-like, putative splicing proteins from Arabidopsis allows yeast cells to tolerate higher lithium and sodium concentrations. Protection against salt stress appears to require the in vivo phosphorylation of these plant polypeptides, since the yeast SR protein kinase Sky1p, which was able to phosphorylate in vitro at least one of them, also proved to be essential for the observed salt tolerance phenotype. In addition, a clone encoding the U1A protein, a previously characterised Arabidopsis splicing factor, was also isolated in the screening. No signi®cant decrease in the intracellular concentration of lithium was observed in yeast cells incubated in the presence of LiCl upon expression of any of the Arabidopsis proteins, suggesting that their effects are not mediated by the stimulation of ion transport. In support of the general signi®cance of these data, we also show that the expression of the RS domain of one of the SR-like proteins in transgenic Arabidopsis plants increases their tolerance to LiCl and NaCl. These results point to an important role of pre-mRNA splicing and SR-like proteins in the salt tolerance of eukaryotic cells, offering a novel route to improve this important trait in crop plants.

Proteins that interact with rice pumilio 1

“…In almost all organisms, cyclins play a role in cell cycle regulation, especially during mitotic division. In yeast, overexpression of RCY1 could induce tolerance to LiCl and NaCl 26 . The pSORT software predicted that OsPUM1 is localized in the cytoplasm.…”

Molecular Characterization and Phylogeny of U2AF35 Homologs in Plants

“…In addition, overexpression of an SR protein kinase in Arabidopsis caused delayed flowering and leaf morphology changes (Savaldi-Goldstein et al, 2003). Altered expression level of some other splicing-related genes will affect the response to drought (Xiong et al, 2001), cold (Gong et al, 2005), and salt resistance (Forment et al, 2002) in plants. It seems likely that many more connections between pre-mRNA splicing and plant responses to stress and environment are yet to be discovered.…”

Stress-tolerant Wild Plants: a Source of Knowledge and Biotechnological Tools for the Genetic Improvement of Stress Tolerance in Crop Plants

“…In fact, some positive results have been obtained by expression of genes encoding ion transporters, enzymes of osmolyte biosynthesis, specific 'anti-stress' proteins or antioxidant enzymes, which conferred, indeed, variable levels of tolerance to drought, salinity, high temperatures and/or other abiotic stresses. In our laboratory, two A. thaliana genes, encoding splicing factors of the SR-like family, were isolated based on the tolerance to LiCl conferred by their expression in yeast, and were shown as well to increase salt (LiCl and NaCl) tolerance when overexpressed in transgenic Arabidopsis plants (Forment et al, 2002). More recently, we have confirmed that these 'SR-like' proteins also confer a marked drought-resistance phenotype to the transgenics (Bourgon et al, 2007).…”