SALT-INDUCED CHLOROPLAST PROTEIN (SCP) is Involved in Plant Tolerance to Salt Stress in Arabidopsis

Soil salinization threats the agricultural production and food security worldwide. Salt stress induced plant senescence and chloroplast degradation. However, it remains largely unknown how the chloroplast-localized proteins affect plant response to salt stress. Here, we characterized a novel gene (At5g39520) in Arabidopsis, which is induced by salt stress and encodes a chloroplast-localized protein. Thus, this gene was named SALT-INDUCED CHLOROPLAST PROTEIN (SCP). A T-DNA insertion mutant of SCP gene (scp-1) showed the enhanced tolerance to salt stress, as indicated by the increased survival rates, fresh weights and chlorophyll contents compared with wild type plants under salt treatment. Salt-induced leaf senescence was also delayed in scp-1 mutant. The scp-1 complementation line and SCP overexpression lines displayed the hypersensitivity to salt stress. The qRT-PCR analysis indicated that the transcripts of CHLOROPLAST VESICULATION (CV), which mediates stress-induced chloroplast degradation, were altered in scp-1 mutant and SCP overexpression lines. Taken together, our results suggest that SCP gene plays a negative role in response to salt stress and has potential application for genetic modification of improving plant tolerance to salt stress.