The Receptor-Like Kinase SIT1 Mediates Salt Sensitivity by Activating MAPK3/6 and Regulating Ethylene Homeostasis in Rice  . Issue 6 (6th June 2014)

• Record Type: Journal Article
• Authors: Li, Chen-Hui; Wang, Geng; Zhao, Ji-Long; Zhang, Li-Qing; Ai, Lian-Feng; Han, Yong-Feng; Sun, Da-Ye; Zhang, Sheng-Wei; Sun, Ying
• Is Part Of: The Plant Cell. Volume 26:Issue 6(2014)
• Page Start: 2538
• Page End: 2553
• Publication Date: 2014-06-06
• DOI: 10.1105/tpc.114.125187
• Languages: English
• ISSNs: 1040-4651

Abstract

Abstract : High salinity inhibits plant growth and can cause plant death. This work identified a root cell–expressed receptor-like kinase that mediates salt sensitivity by activating MAPK and upregulating ethylene synthesis, leading to an increase in the level of reactive oxygen species. Abstract: High salinity causes growth inhibition and shoot bleaching in plants that do not tolerate high salt (glycophytes), including most crops. The molecules affected directly by salt and linking the extracellular stimulus to intracellular responses remain largely unknown. Here, we demonstrate that rice ( Oryza sativa ) Salt Intolerance 1 ( SIT1 ), a lectin receptor-like kinase expressed mainly in root epidermal cells, mediates salt sensitivity. NaCl rapidly activates SIT1, and in the presence of salt, as SIT1 kinase activity increased, plant survival decreased. Rice MPK3 and MPK6 function as the downstream effectors of SIT1. SIT1 phosphorylates MPK3 and 6, and their activation by salt requires SIT1. SIT1 mediates ethylene production and salt-induced ethylene signaling. SIT1 promotes accumulation of reactive oxygen species (ROS ), leading to growth inhibition and plant death under salt stress, which occurred in an MPK3/6- and ethylene signaling-dependent manner in Arabidopsis thaliana . Our findings demonstrate the existence of a SIT1-MPK3/6 cascade that mediates salt sensitivity by affecting ROS and ethylene homeostasis and signaling. These results provide important information for engineering salt-tolerant crops.