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Radish (Raphanus sativus) is a Brassica vegetable important for human nutrition and health because it is rich in diverse metabolites. Although previous studies have evaluated various metabolites, few studies have comprehensively profiled the primary and secondary metabolites in the roots of white- and green-colored radishes. Thus, this study aimed to provide information about the contents of metabolites beneficial for human health in both cultivars and to investigate the relationships between the various metabolites detected. In particular, among the 55 metabolites detected in radish roots, the levels of most amino acids and phenolic acids, vital to nutrition and health, were higher in green radish roots, while slightly higher levels of glucosinolates were observed in white radish roots—information which can be used to develop an effective strategy to promote vegetable consumption. Furthermore, glutamic acid, as a metabolic precursor of amino acids and chlorophylls, was positively correlated with other amino acids (cysteine, tryptophan, asparagine, alanine, serine, phenylalanine, valine, isoleucine, proline, leucine, beta-alanine, lysine, and GABA), and chlorophylls (chlorophyll a and chlorophyll b) detected in radish roots and phenylalanine, a metabolic precursor of phenolic compounds, were positively correlated with kaempferol, 4-hydroxybenzoate, and catechin. In addition, strong positive correlations between carbohydrates (sucrose and glucose) and phenolics were observed in this study, indicating that sucrose and glucose function as energy sources for phenolic compounds.

Heracleum moellendorffii Hance is a non-woody forest plant widely used in China, Korea, and Japan because of its various therapeutic properties. However, the genetic details of the carotenoid pathway (CP), xanthophyll pathway (XP), and apocarotenoid pathway (AP) genes have not been studied. Thus, the CP, XP, and AP genes of H. moellendorffii were detected and analyzed. A total of fifteen genes were identified, of which eight, four, and three belonged to CP, XP, and AP, respectively. All identified genes possessed full open reading frames. Phylogenetic characterization of the identified gene sequences showed the highest similarity with other higher plants. Multiple alignments and 3D dimensional structures showed several diverse conserved motifs, such as the carotene-binding motif, dinucleotide-binding motif, and aspartate or glutamate residues. The results of real-time PCR showed that the CP, XP, and AP genes were highly expressed in leaves, followed by the stems and roots. In total, eight different individual carotenoids were identified using HPLC analysis. The highest individual and total carotenoid content were achieved in the leaves, followed by the stems and roots. This study will provide more information on the gene structure of the CP, XP, and AP genes, which may help to increase the accumulation of carotenoids in H. moellendorffii through genetic engineering. These results could be helpful for further molecular and functional studies of CP, XP, and AP genes.

Rapeseed is an economically important oilseed crop throughout the world. We examined the content and composition of glucosinolates (GSLs) and phenolics in the sprouts of seven Korean cultivars. A total of eight GSLs that include four aliphatic GSLs (AGSLs) (progoitrin, gluconapin, gluconapoleiferin, and glucobrassicanapin) and four indole GSLs (IGSLs) (4-methoxyglucobrassicin, 4-hydroxyglucobrassicin, neoglucobrassicin, and glucobrassicin) were identified in these cultivars. Of the total GSLs, the highest level was detected for progoitrin, while the lowest level was identified for glucobrassicanapin in all the cultivars. Phenolics that include chlorogenic acid, catechin hydrate, 4-hydroxybenzoic acid, gallic acid, ferulic acid, p-coumaric acid, epicatechin, caffeic acid, rutin, quercetin, trans-cinnamic acid, benzoic acid, and kaempferol were present in all the cultivars. Of these, rutin was identified with the highest level while trans-cinnamic acid was identified with the lowest level in all the cultivars. Cluster analysis revealed the unique metabolic signature of eight GSLs and thirteen phenolics for the seven cultivars of rapeseed, which implies that genomic commonality and variability resulted from the previous breeding program. Further, gene expression and cis-regulatory elements suggest that the biosynthesis of GSLs and phenolics of these cultivars appears to be regulated through transcription factors associated with stress responses, phytohormones, and cellular growth.