The modulation of light quality on carotenoids in maize (Zea mays L.) sprouts

• Red and blue light were associated with increased carotenoid biosynthesis. • Lutein contents increased to 6.3 and 14 folds following red and blue light exposure. • Blue light was associated with higher expression of HY5 and CHYB . • ERF021 and MYB68 were negatively associated with carotenoid biosynthesis. • Phytohormones (IAA, SL and GA) were related to carotenoid biosynthesis. The present study aimed to identify the regulatory mechanisms of red, blue, and white light on carotenoid biosynthesis in maize sprouts. Determinations of carotenoid, chlorophyll and phytohormone profiles, as well as relative gene expression, were explored. The results identified enhancement of carotenoid and chlorophyll production as well as gene expression. Most notably, the expression levels of CRY , HY5 , and beta-carotene 3-hydroxylase genes peaked under blue light. Photomorphogene-related hormone, auxins and strigolactone production was also altered under different lights and might have a role in carotenoid metabolism. Gibberellins competed with carotenoids for the precursor geranylgeranyl diphosphate and were hindered by certain light characteristics, probably via DELLA-PIF4 signalling. ERF021 and MYB68 were negative regulators of carotenoid biosynthesis in maize sprouts. These findings provide new insights into the light-regulated mechanism and biofortification of carotenoids in maize sprouts.