Transcriptome and metabolome profiling to elucidate mechanisms underlying the blue discoloration of radish roots during storage.

• We explored differences between white radish (WR) and blue radish during storage. • Transcriptome and metabolome profiling revealed several DEGs and DAMs. • A high correlation was present between transcriptome and metabolome profiles. • Energy metabolism and glucosinolate synthesis were accountable for bluing. • Oxidation and reduction systems were also responsible for blue discoloration. The internal blue discoloration of radish roots (Raphanus sativus) during storage affects their quality. We here performed transcriptome and metabolome profiling to investigate the mechanisms underlying the bluing of radish roots during storage. On comparing white radish (WR) and blue radish (BR), we identified 14,171 differentially expressed genes (upregulated: 7,383, downregulated: 6,788) and 145 differentially accumulated metabolites (upregulated: 117, downregulated: 28). Functional annotation analysis and metabolome profiling revealed that the blue discoloration of radish roots was promoted by high content of glucosinolates, oxidation system (ROS, CAT, POD) or low reduction system (GSH, GPX, APX, GST, ASA). Our results provide new insights into the underlying metabolic causes of the blue discoloration of radish roots and report candidate genes and metabolites involved in blue compound biosynthesis. [ABSTRACT FROM AUTHOR]