Changes in vitamin C, vitamin E, and carotenoid metabolism during early kernel development in maize

BACKGROUND Maize ( Zea mays L.), as the most widely cultivated cereal and a dietary cornerstone, provides not only carbohydrates but also essential micronutrients critical for human health, including vitamin C, vitamin E, and carotenoids. However, conventional maize varieties typically exhibit suboptimal levels of these compounds. This study investigated the dynamic accumulation of vitamin C, vitamin E, and carotenoids, along with their transcriptional regulation, during early kernel development (9–15 days after pollination (DAP)) in maize. RESULTS Combined metabolite and transcriptome analyses showed a 23‐fold increase in vitamin C content, associated with enhanced expression of the gene VTC2 . Id1 and AGAMOUS‐like MADS‐box transcription factors (TFs) are putative regulators, targeting the promoters of GalDH and VTC2 to regulate vitamin C biosynthesis. Vitamin E showed isomer‐specific fluctuations during early kernel development, mainly associated with the expression of VTE1 , VTE2 , and VTE4 , and potentially regulated by knotted 1 and the AGAMOUS‐like MADS‐box TFs via VTE2 and VTE3 , respectively. Total carotenoid content tripled, with zeaxanthin becoming dominant by 15 DAP, driven by upregulated PSY1 and CHYB‐1 . ERF003 was identified as a candidate regulator of PSY3 . CONCLUSION The increases in vitamin C and carotenoid content, and the fluctuation of vitamin E isomers during early maize kernel development, were associated with the modulation of key genes and putative TFs. These findings reveal theoretical insights and provide candidate genetic targets for future breeding efforts aimed at enhancing micronutrient levels in maize.