The S-nitrosylation of monodehydroascorbate reductase positively regulated the low temperature tolerance of mini Chinese cabbage.

One of the main environmental stresses that considerably reduced vegetable yields are low temperature stress. Brassinosteroids (BRs) is essential for controlling a number of physiological functions. Protein S-nitrosylation is thought to be a crucial process in plants that use NO to carry out their biological functions. The exact process by which the mini Chinese cabbage responded to low temperature stress through BR-mediated S-nitrosylation modification of the monodehydroascorbate reductase (MDHAR) is still unknown. BR significantly increased the S-nitrosoylation level and antioxidant capacity at low temperature. One noteworthy development was the in vitroS-nitrosylation of the MDHAR protein. The overexpressed lines exhibited considerably high nitric oxide (NO) and S-nitrosothiol (SNO) contents at low temperature compared to the WT lines. Treatment of the WT and OE-BrMDHAR lines with BR at low temperature increased the antioxidant capacity. According to the biotin signaling, BR considerably enhanced the silenced lines total S-nitrosylation level in vivo at low temperature. Furthermore, BrMDHAR, BrAAO, and BrAPX gene transcript levels were dramatically up-regulated by BR, which in turn reduced the H2O2 content in the silenced lines. These findings demonstrated that the S-nitrosylation of MDHAR was essential to the improvement of BR on low-temperature tolerance in the mini Chinese cabbage.