Correlation analysis of glucosinolate profiles and GSL biosynthetic genes in radishes (Raphanus sativus L.)

Glucosinolates (GSLs) are secondary metabolites that are produced in Brassicale order plants and play an important role in their defense against biotic and abiotic stresses. In addition, GSLs were reported to possess health benefits like anticancer and anti-inflammation activity. In the present study, the GSL profiles of 13 radishes (Raphanus sativus L) cultivars or inbred lines with different root phenotypes were analyzed. A total of four aliphatics and three indolic GSL compounds were consistently detected from all tested radish accessions. Based on the amounts and profiles of the GSL compounds, we identified that glucoraphasatin (GRH) and glucobrassicin (GBS) were the most abundant in the aliphatic and indolic GSLs, respectively, in young radishes. In addition, we performed a correlation heatmap analysis between the profiles of the individual GSL compounds and the GSL biosynthetic genes involved in the secondary modifications. We found that RsGRS1 plays a major role in the highest abundance of GRH in the aliphatic GSLs. Contrastingly, RsCYP81F3 and its paralogs, RsCYP81Fs might contribute to the profiles of the indolic GSLs in young radishes. In this study, we found that there was a substantial correlation between the transcription of the genes involved in the secondary modification phase of the GSL biosynthetic pathway and the profiles of the aliphatic and indolic GSL compounds.