Post-translational modification omics reveals the early-stage response of Chinese cabbage to Cd stress

High concentrations of cadmium (Cd) in the soil first endanger the growth of crops and can also cause diseases to the human body through crops. Chinese cabbage ( Brassica rapa var. glabra Regel ) tends to accumulate cadmium (Cd), harming its growth and causing economic losses. Although both transcriptomics and proteomics have been used to study the molecular mechanisms of Cd tolerance, protein modification omics has not yet been used to study the tolerance mechanism of Chinese cabbage to Cd stress. Here, we used S -nitrosylation omics, data-independent acquisition phosphorylation omics, and ubiquitination omics analyses to found that under Cd stress, 952 differential S-nitrosylated proteins, 1863 differential phosphorylated proteins, and 122 differential ubiquitinated proteins were enriched. We identified 10 key candidates, including HMA1 and CCS, that may mediate Cd tolerance through specific PTMs. The S -nitrosylation of plant proteins is regulated by nitric oxide (NO), and exogenous application of the NO donor sodium nitroprusside (SNP) improved the tolerance of Chinese cabbage seedlings to Cd. Exogenous application of 250 µM SNP considerably increased the antioxidant enzyme activities of Chinese cabbage seedlings, reduced the ROS and MDA content, and enhanced Cd resistance compared with the sole 1 mM Cd treatment. • Post-translational modifications of proteins in Chinese cabbage under Cd stress • Early responses of Chinese cabbage under Cd stress • Predicted post-translationally modified proteins in response to heavy metal stress • Exogenous SNP application enhances cadmium tolerance in Chinese cabbage