The molecular regulation of folate accumulation in pakchoi by low intensity white light-emitting diode (LED) illumination

Abstract

The objective of the present study was to determine the effect of white LED illumination on the level of folate and its precursors, synthesis-related enzymes, and the expression of their corresponding genes in pakchoi stored at 20 °C. Results indicated that LED (10 μmol m−2 s−1) illumination decreased the level of 7,8-dihydroneopterin (DHN), 6-hydroxymethyl-7.8-dihydropterin (HMDHP), 7,8-dihydrofolate (DHF), chorismate, and 4-amino-4-deoxychorismate (ADC), and increased the level of folate 7.8-dihydroneopterin 3’-triphosphate (DHN-P3), 6-hydroxymethyldihydropterin pyrophosphate (HMDHP-P2), dihydropteroate (DHP), Tetrahydrofolate (THF), polyglutamyl tetrahydrofolatein (THF-Glu(n)) and p-aminobenzoate (pABA). Additionally, the level of guanosine triphosphate cyclohydrolase I (GTPCHI), 7,8-dihydrofolate reductase (DHFR), and folylpolyglutamate synthetase (FPGS) were also reduced, as was the expression level of their corresponding genes. LED illumination also increased the level of 7,8-dihydrofolate synthetase (DHFS), amino deoxychorismate synthetase (ADCS), and amino deoxychorismate lyase (ADCL), and the expression of their corresponding genes. The LED treatment, however, did not have much impact on the level of guanosine triphosphate (GTP) and γ-glutamyl hydrolase (GGH). The analysis of differentially expressed genes (DEGs) indicated that the white LED illumination treatment had a significant impact on folate biosynthesis. In summary, white LED illumination had a regulatory impact on folate metabolism in harvested pakchoi and extended its postharvest quality.