Proline metabolism regulation in Spartina alterniflora and SaP5CS2 gene positively regulates salt stress tolerance in transgenic Arabidopsis thaliana

ABSTRACT It has been discovered that many plants accumulate proline in response to osmotic stress. However, the interaction between salinity stress and proline metabolism-related genes has not been unequivocally identified in Spartina alterniflora. In our research, we successfully cloned key genes: SaP5CS1 and SaP5CS2, SaOAT, SaProT and correlated with expression profiles including SaPDH were also investigated. As the key enzyme genes for proline metabolism, the up-regulated expression of SaP5CS2 played a leading part under salt stress. Chlorophyll contents decreased gradually degree in leaves with prolonged salt stress time. Additionally, transgenic Arabidopsis overexpressing SaP5CS2 showed high tolerance to salt stress and accumulated more proline and H2O2 content was also reduced in salt stress condition. This study provided a foundation for deciphering the molecular osmoregulation underlying proline metabolism in S. alterniflora and SaP5CS2 may play an important role in conferred salinity tolerance by the regulation of proline.