Influence of amphetamine, γ-aminobutyric acid, and fosmidomycin on metabolic, transcriptional variations and determination of their biological activities in turnip (Brassica rapa ssp. rapa)

• AMP and GABA treatment increases the GSLs and phenolic compounds.
• Lutein was decreased in AMP-, GABA-, and FOS-treated than control plants.
• GABA treatment increases the MDA and H2O2 and decreases chlorophyll levels.
• AMP, GABA, and FOS treatment showed upregulated gene expression of metabolics.

The impact of amphetamine (AMP), γ-aminobutyric acid (GABA), and fosmidomycin (FOS) on the contents of glucosinolates (GSLs), polyphenols, carotenoids, chlorophyll, anthocyanin, malondialdehyde, hydrogen peroxide, antioxidant, antimicrobial activities, and gene regulation of phytochemicals biosynthesis was studied in turnip plants. The AMP and GABA treatments were significantly increased the amount of GSLs. FOS-treated plants were obviously decreased the level of GSLs. Total phenolic, flavonoid contents, antioxidant, and antimicrobial activities were substantially increased in FOS-, GABA-, and AMP-treated plants. Lutein was higher in control compared to treated plants. The chlorophyll content considerably decreased, while anthocyanin, malondialdehyde, and hydrogen peroxide levels significantly increased with under GABA treatment. Furthermore, AMP-, GABA-, and FOS-treated plants were showed significant induction of expression of genes related to the secondary metabolites. These results demonstrated that the AMP and GABA significantly increased the contents of health-promoting compounds and enhanced biological activities in turnip plants.