Mulberry RGS negatively regulates salt stress response and tolerance

Abstract

Regulator of G-protein signaling (RGS) protein, the best-characterized accelerating GTPase protein in plants, regulates G-protein signaling and plays important role in abiotic stress tolerance. However, the detailed molecular mechanism of RGS involved in G-protein signaling mediated abiotic stress responses remains unclear. In this study, a mulberry (<i>Morus alba</i> L.) <i>RGS</i> gene (<i>MaRGS</i>) was transformed into tobacco, and the ectopic expression of <i>MaRGS</i> in tobacco decreased the tolerance to salt stress. The transgenic tobacco plants had lower proline content, higher malonaldehyde and H₂O₂ contents than wild type plants under salt stress condition. Meanwhile, <i>MaRGS</i> overexpression in mulberry seedlings enhances the sensitivity to salt stress and RNAi-silenced expression of <i>MaRGS</i> improves the salt stress response and tolerance. These results suggested that MaRGS negatively regulates salt stress tolerance. Further analysis suggested that D-glucose and autophagy may involve in the response of RGS to salt stress. This study revealed the role of <i>MaRGS</i> in salt stress tolerance and provides a proposed model for RGS regulates G-protein signaling in response to salt stress.