High throughput sequencing identifies chilling responsive genes in sweetpotato (Ipomoea batatas Lam.) during storage

Sweetpotato (Ipomoea batatas L.) is a globally important economic food crop. It belongs to Convolvulaceae family and origins in the tropics; however, sweetpotato is sensitive to cold stress during storage. In this study, we performed transcriptome sequencing to investigate the sweetpotato response to chilling stress during storage. A total of 110,110 unigenes were generated via high-throughput sequencing. Differentially expressed genes (DEGs) analysis showed that 18,681 genes were up-regulated and 21,983 genes were down-regulated in low temperature condition. Many DEGs were related to the cell membrane system, antioxidant enzymes, carbohydrate metabolism, and hormone metabolism, which are potentially associated with sweetpotato resistance to low temperature. The existence of DEGs suggests a molecular basis for the biochemical and physiological consequences of sweetpotato in low temperature storage conditions. Our analysis will provide a new target for enhancement of sweetpotato cold stress tolerance in postharvest storage through genetic manipulation. Overall design: Sweetpotato cultivar Xushu 18 (I. batatas L. cv. Xushu 18) was kindly provided by the Chinese Academy of Agricultural Science.The sweetpotato were randomly divided into two groups, which were stored at 4 °C (LTC) or 14 °C (ATC) and with a relative humidity of 85%, respectively. Each group had the same number of samples. Sweetpotato not stored at the abovementioned specific conditions were considered members of the not stored condition group (CK). Sample tissues were collected every other week while in storage, immediately frozen in liquid nitrogen, and then stored at -80 °C prior to analysis. To minimize variations, seven sweetpotato tuberous roots were pooled into one biological replicate, and three biological replicates were assessed at each time point. To screen genes associated with root tuber response to low temperature, transcriptome sequencing of sweetpotato roots in different temperature (CK, ATC and LTC) was performed.