A glycine-rich RNA-binding protein can mediate physiological responses in transgenic plants under salt stress.

Glycine-rich RNA-binding proteins (GRPs) are involved in post-transcriptional regulation of genes, which have been found to play a role in stress response. However, whether GRPs can mediate some physiological responses related to salt stress tolerance is still not known. In the present study, we investigated the role of GRPs in salt stress-induced physiological responses by generating transgenic tobacco lines overexpressing a GRP (LbGRP1) gene from Limonium bicolor (Bunge) Kuntze. Compared with wild type (WT) tobacco, the transgenic plants showed significantly improved superoxide dismutase and catalase activities under salt stress conditions. Levels of proline in the transgenic plants were significantly higher than those in the WT plants grown under NaCl stress conditions. Furthermore, Na(+) content and Na(+)/K(+) ratio in the transgenic plants were lower than those in the WT plants under both normal growth and stress conditions. These results suggested that overexpression of the LbGRP1 gene can affect some physiological processes associated with salt tolerance of plants. Therefore, we hypothesize that LbGST1 can enhance stress resistance by mediating some physiological pathways.