Background: Finger millet (Eleusine coracana (L.) Gaertn.) is a better orphan cereal crop with good nutrition native to sub-Saharan Africa and South Asia. With its impressive levels of calcium, density of dietary fibre and richness of bioactive phytochemicals, it is a leading candidate for tackling global micronutrient deficiencies and supporting climate-resilient food systems. Finger millet is agronomically resilient, but the full metabolic complexity is not yet fully understood, limiting targeted nutritional improvement.
Objectives: The present study was aimed at comprehensive profiling of nutritional and phytochemical metabolome of different Eleusine coracana genotypes by employing high throughput analytical platforms and delineation of biofortification strategies based on metabolomics evidence.
Methods: Untargeted and targeted metabolomic profiling was performed using liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) spectroscopy. Metabolite annotation was done by integration with KEGG, HMDB and MetaboAnalyst databases. We applied pathway enrichment analyses, quantitative trait loci (QTL) mapping and genome-wide association studies (GWAS) to identify the genetic determinants of metabolite accumulation. The effects of biofortification were assessed by CRISPR/Cas9-mediated editing of the phytate biosynthesis genes and marker-assisted selection (MAS) protocols.
Results: The identification of more than 1,200 potential metabolites, including phenylpropanoids, flavonoids, organic acids and amino acids, and mineral-chelators by metabolomic profiling. Significant associations of genotype variation in calcium (287 to 491 mg/100 g) and iron (3.4 to 7.8 mg/100 g) with metabolomic profiles were observed. Significantly improving the bioavailability of iron in selected lines through anti-nutritional factor reductions achieved via upregulation of phytase through CRISPR technology resulted in an increase of 38%. Machine-learning-assisted metabolomic analyses have produced many new candidate biomarkers of stress tolerance and mineral density.
Conclusion: Transformative opportunities exist for developing a system-wide biofortification system for Eleusine coracana through utilization of metabolomics-based methodologies. Combining the use of multi-omics technology platforms, genome editing via precision (gene) technologies/precision crop breeding, and artificial intelligence in assisting to identify metabolites provides a strategic roadmap for the creation of nutritionally enriched, climate-tolerant cultivars of finger millet to address the challenges of food security worldwide.