An Omics Study of Iron and Zinc Homeostasis in Finger Millet: Biofortified Foods for Micronutrient Deficiency in an Era of Climate Change?

The future of food and sustainability of the staple food crops are of utmost importance in the 21st century. Micronutrient deficiency, for example, in iron and zinc, is a common cause of human diseases. Mineral content of the staple food crops has therefore crosscutting importance for food engineering and planetary health. Finger millet, a staple food of agricultural importance worldwide, is rich in iron and zinc, and an ideal model to study the prospects of biofortified foods in times of climate change. We report here a multiomics study of the iron and zinc homeostasis in the finger millet. We identified and characterized 15 candidate genes potentially involved in iron and zinc homeostasis pathways in the finger millet. Structural and functional annotation of the candidate genes revealed a high similarity index with their respective homologs (Oryza sativa, Triticum aestivum, Zea mays, Hordeum vulgare, and Setaria italica). Transcriptome-wide expression analysis showed that genes involved in uptake and translocation of iron and zinc are highly expressed in the GP-1 genotype, while those involved in bioavailability of iron and zinc are expressed more in the GP-45 genotype of the finger millet. In conclusion, finger millet, being a stress-resilient crop, utilizes a combination of strategies in iron and zinc homeostasis pathway, which appear to play an important role in food crop acquisition of iron and zinc, despite environmentally limiting conditions. These data offer molecular insights on iron and zinc accumulation and paves the way for new strategies toward staple food crop with mineral biofortification.