Effect of NaCl stress and supplemental CaCl₂ on carotenoid accumulation in germinated yellow maize kernels

Germinated edible seeds and sprouts are becoming increasingly common in the human diet because they are rich in bioactive compounds and antioxidants and are highly nutritious. In this study, the effects of NaCl stress and supplemental CaCl₂ on carotenoid accumulation, antioxidant capacity and expression of key enzymes in yellow maize kernels were investigated. The results showed that the lutein and zeaxanthin contents increased with NaCl treatment, and further increased with supplemental CaCl₂. Additionally, germinated yellow maize kernels showed increased antioxidant capacity in response to NaCl and CaCl₂. The transcript levels of carotenogenic genes ZmPSY and ZmCYP97C were upregulated and the expression levels of ZmLCYB and ZmBCH1 were downregulated under NaCl stress. The expression of all key carotenogenic genes was upregulated by CaCl₂ supplementation. These results suggested that NaCl and CaCl₂ contribute to carotenoid accumulation via increased expression of related carotenogenic genes and increased antioxidant capacity in germinated yellow maize kernels.