Potato tonoplast sugar transporter 1 controls tuber sugar accumulation during postharvest cold storage

Abstract

Cold-induced sweetening (CIS), the undesirable sugar accumulation in cold-stored potato ( Solanum tuberosum L.) tubers, is a severe postharvest issue in the potato processing industry. Although the process of sucrose hydrolysis by vacuolar invertase during potato CIS is well understood, there is limited knowledge about the transportation of sucrose from the cytosol to the vacuole during postharvest cold storage. Here, we report that among the three potato tonoplast sugar transporters (TSTs), StTST1 exhibits the highest expression in tubers during postharvest cold storage. Subcellular localization analysis demonstrates that StTST1 is a tonoplast-localized protein. StTST1 knockdown decreases reducing sugar accumulation in tubers during low-temperature storage. Compared to wild-type, potato chips produced from StTST1-silenced tubers displayed significantly lower acrylamide levels and lighter color after cold storage. Transcriptome analysis manifests that suppression of StTST1 promotes starch synthesis and inhibits starch degradation in cold-stored tubers. We further establish that the increased sucrose content in the StTST1-silenced tubers might cause a decrease in the ABA content, thereby inhibiting the ABA-signaling pathway. We demonstrate that the down-regulation of β-amylase StBAM1 in StTST1-silenced tubers might be directly controlled by ABA-responsive element-binding proteins (AREBs). Altogether, we have shown that StTST1 plays a critical role in sugar accumulation and starch metabolism regulation during postharvest cold storage. Thus, our findings provide a new strategy to improve the frying quality of cold-stored tubers and reduce the acrylamide content in potato chips.

Acknowledgements

This work was supported by the National Natural Science Foundation of China (31871683 and 32101781), the earmarked fund for the China Modern Agro-industry Technology Research System (CARS-09, Potato).

Author contributions

B.N. and B.S. conceived the research. Te.L. and B.N. designed the study. Te.L., M.A.K., S.B., E.W., and T.Z. performed the experiments. Te.L., S.J., Ti.L., and L.Y. analysed the data. Te.L. drafted the manuscript. B.N. and B.S. revised the manuscript.

Data availability

The data and materials used to support the findings of this study are available from the corresponding author upon request.

Conflicts of interest statement

The authors declare no conflict of interest.

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