The beneficial functions of blue light supplementary on the biosynthesis of glucosinolates in pakchoi (Brassica rapa L. ssp. chinensis) under greenhouse conditions

Abstract

Blue light can improve the nutritional value of vegetables grown in greenhouse, while the mechanisms about the biosynthesis and accumulation of glucosinolates regulated by light signaling still unknown. Here, the soluble amino acid and glucosinolate profiles under supplementary different blue light intensities (T50, T100, T150) for 10 days were investigated in green-leaf and red-leaf pakchoi. The results indicated that blue light could significantly increase the contents of glucoalyssin, glucobrassicin, glucobrassicanapin, gluconapin and total glucosinolates, and shown a dose effect. The soluble amino acid profiles and the contents of glucosinolates precursor amino acid were also enhanced to varying degrees. Besides, in green-leaf and red-leaf pakchoi, the expression levels of photoreceptor genes under T100 were significantly higher compared with the CK. Supplementary blue light also promoted the expression of key transcription factors and key genes of glucosinolate biosynthesis pathway in two cultivars pakchoi. Therefore, the beneficial functions of blue light supplementary on the biosynthesis of glucosinolates in pakchoi under greenhouse conditions are owing to the promoted in the contents of precursor amino acids and the expressions of glucosinolate-related genes mediated by light signal transduction. • Supplementary bule light could increase the glucosinolate profiles of pakchoi leaves. • The increasing of glucosinolate content be linked to glucosinolate biosynthesis and photoreceptor gene-related expressions. • The increasing of light-controlled amino acids profiles provides the material basis for glucosinolate biosynthesis. • The respond sensitivity to bule light was different in green-leaf and red-leaf pakchoi.