The MnBPC6-MnPLATZ5 module regulates the salt stress tolerance of mulberry

Salt stress is the main environmental problem that limits plant growth and crop productivity. The salt overly sensitive (SOS) signaling pathway is crucial in mediating plant responses to salt stress. However, the functional genes and mechanisms that regulate the transcription of SOS pathway genes under salt stress remain unclear. In this study, we found that plants rich in AT sequences and zinc-binding (MnPLATZ5) transcription factors may be involved in response of mulberry trees to salt stress by inhibiting the expression of MnHAK5/MnSOS3. The upregulation of the MnPLATZ5 gene reduced the salt tolerance in mulberry trees. Furthermore, MnBPC6 downregulates the expression of MnPLATZ5. Through the overexpression of MnBPC6 in mulberry trees, MnBPC6 can positively regulate the salt stress tolerance of mulberry trees. Genetic analysis confirmed that MnPLATZ5 responded to salt stress downstream of MnBPC6. These findings provide a MnBPC6-MnPLATZ5-MnHAK5/MnSOS3 regulatory module for regulating the mulberry tree's response to salt stress.