A proteomic analysis of storage stress responses in Ipomoea batatas (L.) Lam. tuberous root.

During post-harvest storage, tuberous roots of sweet potato (Ipomoea batatas L. Lam.) usually undergo a biotic and abiotic stress influencing protein expression pattern and substance contents. This research compared the change of total proteins and carbohydrate content in tuberous roots of sweet potato during the storage period. The result of the two-dimensional electrophoresis analysis demonstrated that there were 25 differentially expressed proteins between day 0 and day 75 during the storage. Among these proteins, 11 proteins were down-regulated and the other 14 were up-regulated. The results from MALDI-TOF-TOF/MS analyses and mascot database searching showed that 11 of the 25 differentially expressed proteins were identified as store-stress regulated proteins. It was also found that the proteins involved in the energy metabolism and the stress-response were drastically up-regulated, whereas those in biomacromolecule synthesis were markedly down-regulated. Meanwhile, under the experimental conditions, the content of the starch and the cellulose was decreased by more than a quarter and the amylase activity was increased moderately.