Ultrasound and γ-aminobutyric acid improve quality of Chinese kale sprouts through coordinated metabolic regulation: insights from multi-omics analysis.

Brassica sprouts are valued for their abundant bioactive compounds and strong antioxidant capacity. This study evaluated the effects of ultrasound, γ-aminobutyric acid (GABA), and their combination on the growth, nutritional quality, and metabolic regulation of Chinese kale sprouts. All treatments promoted growth and enhanced soluble sugars, proteins, pigments, antioxidant-related compounds, and glucosinolates, although their effects varied among quality attributes. The combined treatment produced pronounced improvements in plant height, soluble sugars and proteins, pigments, and ascorbic acid. Metabolomic and transcriptomic analyses revealed coordinated regulation of primary and secondary metabolism, involving carbohydrate and glutathione metabolism, phenylpropanoid biosynthesis, and glucosinolate biosynthesis. Weighted gene co-expression network analysis identified CAD and COMT as hub genes, along with key transcription factors including WRKY75, GATA22, MYB108, and ERF113. These findings indicate that ultrasound and GABA improve sprout quality through coordinated metabolic and transcriptional regulation, providing a theoretical basis for the application of elicitation strategies in sprout production.