Red light enhances folate accumulation in wheat seedlings.

Red, white, blue, green, and yellow lights were applied to investigate their effects on folate accumulation in wheat seedlings. The different lights, especially red light, significantly increased the total folate content. Total folate showed maximum accumulation under 30 μmol/(m2·s) of red light, with an increase of 24% compared with the control (darkness). 5-Methyl-tetrahydrofolate (5-CH3-THF) was the dominant folate component, and was significantly increased by red light irradiation. In addition, under red light, the folate content of leaves was higher and more sensitive to light than that of endosperm or roots. Red light up-regulated the expression of guanosine triphosphate (GTP) cyclohydrolase 1 (GCH1) and aminodeoxychorismate synthase(ADCS), enhanced the activity of GCH1 and ADCS, and increased the content of precursors of folate synthesis, including pterin and p-aminobenzoic acid (pABA). Hence, the increased folate accumulation promoted by light could be attributed to the increased content of folate synthesis precursors, the activity of key enzymes, and related gene expression.