Review Article

Toward high-protein rice: breeding, genomics, and metabolic strategies for improving grain protein accumulation

Sheetanshu Gupta

Assistant Professor, Department of Food Safety and Quality Assurance, College of Food Technology,

Central Agriculture University, Imphal, Manipur, India

*Corresponding author e-mail: anshus279@gmail.com

(Received: 30/01/2026; Revised: 25/04/2026; Accepted: 12/06/2026; Published: 20/06/2026)

ABSTRACT

Rice is the primary staple food for more than half of the world’s population, yet its milled grain typically contains only modest levels of protein compared with other cereals and grain legumes. Improving grain protein content and quality in rice is therefore an important goal for nutritional security, especially in regions where rice supplies a large fraction of daily calories and access to diverse protein sources is limited. Over the past two decades, significant progress has been made in understanding the genetic, genomic, and physiological basis of protein synthesis, deposition, and storage in the rice endosperm. This has enabled breeders and biotechnologists to identify key quantitative trait loci (QTLs), regulatory genes, transporters, and metabolic pathways that control both total grain protein content and the composition of storage proteins such as glutelins, prolamins, albumins, and globulins. Conventional and marker-assisted breeding have been used to introgress high-protein alleles into elite backgrounds, while genomic selection offers new opportunities to accelerate genetic gain for protein traits without sacrificing yield. At the same time, functional genomics and transcriptomics have revealed critical roles for amino acid transporters, transcription factors, and endomembrane trafficking components in governing protein loading and accumulation in seeds. More recently, transgenic and genome-editing strategies, including targeted modification of amino acid transporters and regulators of nitrogen assimilation, have demonstrated the potential to elevate grain protein content and improve amino-acid balance with minimal penalties to agronomic performance. However, trade-offs among protein content, grain yield, eating quality, and processing characteristics remain a major challenge.

Keywords: High-protein rice; grain protein content; rice biofortification; quantitative trait loci (QTL); amino acid transporters; functional genomics; genome editing

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