Folate Metabolism and Biofortification in Crop Plants

Folate, or vitamin B9, is an essential cofactor in one-carbon transfer reactions that underpin synthesis of nucleic acids, amino acids and methylation processes in all living organisms. Plants synthesise folate de novo through a pathway that spans plastids, cytosol and mitochondria, involving enzymes that assemble pteridine and p-aminobenzoate moieties before glutamylation to generate polyglutamate forms. Within plant cells, folate compartmentation and polyglutamyl chain length regulate both metabolic flux and storage, ensuring adequate provision of one-carbon units under varying environmental conditions. Staple crops such as rice, maize and wheat are inherently low in folate, contributing to widespread ‘hidden hunger’ and folate-deficiency disorders in humans. Biofortification—through classical breeding, transgenic overexpression or gene‐editing—aims to elevate folate content in edible tissues without compromising yield or stress tolerance. Key challenges include overcoming metabolic bottlenecks, achieving stable subcellular targeting of transgenes, and preserving folate integrity during post-harvest processing. Successful biofortification strategies can significantly improve global dietary folate intake, reduce reliance on pharmacological supplementation and enhance crop resilience.

Research from Nature Portfolio

Comparative genomics across algae and land‐plant lineages has revealed that folate‐biosynthetic enzymes exhibit both conserved cores and lineage‐specific expansions. Studies demonstrate that gene families encoding GTP cyclohydrolase I, aminodeoxychorismate synthase and folylpolyglutamate synthase have diversified in sequence and subcellular targeting, reflecting adaptation to distinct cellular architectures. Mapping of these evolutionary trajectories provides a blueprint for selecting optimal gene orthologues for metabolic engineering. Furthermore, detailed phylogenetic analysis highlights novel regulatory motifs that may govern enzyme stability and interaction, offering routes to enhance folate accumulation with minimal perturbation to endogenous metabolism.

Folate Metabolism and Biofortification in Crop Plants publication trend

The graph below shows the total number of articles in folate metabolism and biofortification in crop plants across all publications each year (not limited to Nature Index journals).

Technical terms

Folate: A B-group vitamin (B9) comprising pteridine, p-aminobenzoate and glutamate units, acting as a carrier of one-carbon units in metabolism.

One-carbon metabolism: Network of biochemical reactions that transfer single carbon groups for synthesis of nucleotides, amino acids and methylation reactions.

Biofortification: Process of increasing the micronutrient content of food crops through breeding, genetic engineering or agronomic practices.

GTP cyclohydrolase I (GCHI): Enzyme catalysing the first step in pteridine biosynthesis, converting GTP to dihydroneopterin triphosphate.

Aminodeoxychorismate synthase (ADCS): Enzyme responsible for producing p-aminobenzoate from chorismate, a precursor of the folate backbone.

Polyglutamation: Addition of glutamate residues to folate to form polyglutamate chains, enhancing retention and activity within cells.

References

1. Folates in Plants: Research Advances and Progress in Crop Biofortification. Frontiers in Chemistry (2017).
2. Evolution of folate biosynthesis and metabolism across algae and land plant lineages. Scientific Reports (2019).
3. Improved folate accumulation in genetically modified maize and wheat. Journal of Experimental Botany (2019).
4. Metabolic engineering of folate and its precursors in Mexican common bean (Phaseolus vulgaris L.). Plant Biotechnology Journal (2016).
5. Toward Eradication of B-Vitamin Deficiencies: Considerations for Crop Biofortification. Frontiers in Plant Science (2018).