Transcriptome analysis of melatonin regulating the transformation of glucoraphanin to sulforaphane in broccoli hairy roots

Sulforaphane (SF) is one of the most effective natural products in preventing and fighting cancer, found in cruciferous plants. In this study, broccoli hairy roots grown for 20 d were used as the experimental material, and it was treated with 500 μmol/L melatonin (MT) for 0, 12 and 32 h to explore the effect of MT on the conversion of glucoraphanin (GRA) to SF. Results showed that the yields of GRA and SF were the largest under MT treatment for 12 h, which were 1.53 and 1.93-fold, respectively, compared to 0 h. However, Myrosinases activity was the highest under MT treatment for 32 h, which was 1.42-fold compared to that of the 0 h. The differential expression of key genes involved in GRA conversion to SF in broccoli hairy roots was identified transcriptome sequencing, and the path of the transformation from GRA to SF was simulated, which provided a theoretical basis for establishing an efficient transformation system from GRA to SF.