Integrated transcriptomic and metabolomic analysis of cultivar differences provides insights into the browning mechanism of fresh-cut potato tubers

The quality of fresh-cut potato tubers is usually impacted by surface browning, which affects food quality. Here, four potato cultivars that differed in their sensitivity to postcutting browning were evaluated with transcriptomics and untargeted metabolomics to investigate the molecular mechanism underlying postcutting browning. The results revealed that the cultivar Yunshu 505 (YS505) was most susceptible to postcutting browning, while Kexin 13 (KX13) was the least susceptible. Compared with KX13, YS505 showed higher PPO (2.5-fold) and POD (32.8-fold and 2.2-fold) mRNA accumulation but lower CAT (0.4-fold) and ACLY (0.4-fold) mRNA accumulation. Transcriptomic analysis also revealed that lipid metabolism and amino acid metabolism were critical to postcutting browning sensitivity, and reactive oxygen species and respiration contributed to browning. Moreover, metabolites related to signal transduction, such as jasmonic acid, glutamate and gibberellins, were found to be enriched in the browning-resistant cultivar KX13. L-aspartic acid and kynurenic acid were inferred to slow browning. Overall, the present study provides novel insights into the browning mechanism of postcutting potato tubers.