Harnessing allelic variation to improve the protein content and amino acid profiles of food legumes

The growing demand for safe and nutritious foods places unprecedented demands on agriculture. Widespread malnutrition in the Global South could be minimized by including legumes in predominantly cereal‐based cropping systems. Regular legume consumption provides multiple health benefits to humans, positively impacts soil health and microbiome diversity, and leaves a smaller environmental footprint (greenhouse gas emission) than other crops. Enhancing the total seed protein content, improving protein quality, and reducing antinutrient levels, including allergenic proteins, should be key priorities. This review summarizes recent progress in understanding changes in protein accumulation and quality during crop legume seed development, the development of a protein atlas for intracellular localization and functional characterization of seed proteins, and the assessment of natural variability in seed protein content and amino acid profiles. It also highlights notable genomic regions and candidate or functionally characterized genes and DNA markers associated with seed protein content and protein quality (based on seed amino acid profiles) and recent advances in developing superior germplasm with enhanced protein content and quality. Finally, it summarizes progress in establishing large‐scale mutant databases as libraries of variation, seed proteome rebalancing to reduce allergenic protein levels, harnessing epistasis and pleiotropic variation, mitigating tradeoffs between seed yield and seed protein content and quality, and biotechnological interventions to increase total seed protein content and levels of sulfur‐containing amino acids. These advances have revealed many unique genetic and genomic resources that could be used to create locally adapted legume crops with improved seed protein content and quality.