Unraveling the Contribution of in Conferring Salinity Tolerance in Mulberry ( Roxb).

Salinity is one of the most serious threats to sustainable agriculture. The Salt Overly Sensitive (SOS) signaling pathway plays an important role in salinity tolerance in plants, and the gene plays a critical role in this pathway. Mulberry not only has important economic value but also is an important ecological tree species; however, the roles of the gene associated with salt stress have not been reported in mulberry. To gain insight into the response of mulberry to salt stress, (designated ) was cloned from mulberry ( Roxb), and sequence analysis of the amino acids of MulSOS2 showed that it shares some conserved domains with its homologs from other plant species. Our data showed that the gene was expressed at different levels in different tissues of mulberry, and its expression was induced substantially not only by NaCl but also by ABA. In addition, was exogenously expressed in Arabidopsis, and the results showed that under salt stress, transgenic plants accumulated more proline and less malondialdehyde than the wild-type plants and exhibited increased tolerance to salt stress. Moreover, the gene was transiently overexpressed in mulberry leaves and stably overexpressed in the hairy roots, and similar results were obtained for resistance to salt stress in transgenic mulberry plants. Taken together, the results of this study are helpful to further explore the function of the gene, which provides a valuable gene for the genetic breeding of salt tolerance in mulberry.