Proteasome shuttle protein DSK2b regulates the enzymatic browning of potato

Potatoes are susceptible to enzymatic browning, which affects the processing and visual quality of potato produce. The proteasome shuttle protein DSK2b was screened to be interacted with two browning-resistant protease inhibitors and DSK2b exhibited higher expression in browning-resistant potato cultivar. Further experiments found that DSK2b expression increased with browning, suggesting a potential browning-regulatory role. Therefore, the effect of DSK2b on potato browning and related mechanisms was investigated by altering DSK2b expression levels. Results showed that DSK2b-overexpression alleviated the browning of potato pulps while RNA-interference of DSK2b aggravated the phenotype. DSK2b negatively affected the free amino acid accumulation, which contributed to potato browning. Besides, DSK2b negatively regulated phenylpropanoid metabolism by modulating key enzymes of PAL, 4CL, and C4H. Concurrently, DSK2b modulated the gene expression and activities of PPO and POD. Transcriptomic and proteomic analyses revealed that DSK2b regulated potato browning, which was closely related to protease inhibitors. This study suggests that DSK2b regulates enzymatic browning in potatoes, offering a novel strategy for mitigating enzymatic browning.