Overexpression of StCYS1 gene enhances tolerance to salt stress in the transgenic potato (Solanum tuberosum L.) plant

Salt stress seriously restricts the growth and yield of potatoes. Plant cystatins are vital players in biotic stress and development, however, their roles in salt stress resistance remain elusive. Here, we report that StCYS1 positively regulates salt tolerance in potato plants. An in vitro biochemical test demonstrated that StCYS1 is a bona fide cystatin. Overexpression of StCYS1 in both Escherichia coli and potato plants significantly increased their resistance to high salinity. Further analysis revealed that the transgenic plants accumulated more proline and chlorophyll under salt stress conditions. Moreover, the transgenic plants displayed higher H2O2 scavenging capability and cell membrane integrity compared with wild-type potato. These results demonstrate that StCYS1 is closely correlated with salt stress and its overaccumulation can substantially enhance salt stress resistance.