Comparative transcriptome reveals distinct starch-sugar interconversion patterns in potato genotypes contrasting for cold-induced sweetening capacity

Potato accumulates large amounts of soluble sugar during cold storage periods. However, a system based understanding of this process is still largely unknown. Here, we compared the dynamic cold-responded transcriptome of genotypes between cold-induced sweetening resistant (CIS-R) and cold-induced sweetening sensitive (CIS-S) in tubers. Comparative transcriptome revealed that activating the pathways of starch degradation, sucrose synthesis and hydrolysis could be common strategies in response to cold in both genotypes. Moreover, the variation in sugar accumulation between genotypes may be due to genetic differences in cold response, which could be mainly explained: CIS-R genotype was active in starch synthesis and attenuated in sucrose hydrolysis by promoting the coordinate expression of aseries ofgenes involved in starch-sugar interconversion. Additionally, transcription factors, the candidate master regulators of starch-sugar interconversion, were discussed. Taken together, this work has provided an avenue for studying the mechanism involved in the regulation of the CIS resistance.

Keywords: Cold-induced sweetening; Comparative transcriptome; Potato; Starch-sugar interconversion.