The Crop Journal study uncovers gene that controls wheat yield and nutrition

Wheat breeders have long struggled to increase yield with sacrificing nutritional quality. A new study from China identifies TaJAZ1 as a key gene behind this trade-off. Using CRISPR to deactivate TaJAZ1, researchers developed wheat lines with dramatically higher grain yield and nearly double the resistant starch content. The findings reveal a genetic strategy for creating wheat varieties that are both more productive and healthier, offering benefits for future food security and metabolic health.

As climate change and population growth put increasing pressure on food systems worldwide, wheat stands out as a major staple crop to ensure food security. Wheat grain, which supplies a substantial portion of the calories consumed globally, is composed of about 70% starch. Starch type and content determine not only how the grain is processed, but also its nutritional value. For decades, wheat breeders have been trying to strike an ideal balance between high productivity (yield) and high nutritional quality.

Achieving this balance, however, is inherently difficult because both starch content and yield are determined by multiple complex genetic traits, themselves also affected by the interactions of different genes and proteins. A desirable trait in wheat is resistant starch—a type of starch that acts like healthy dietary fiber in the body by resisting digestion in the small intestine. Unfortunately, genetic profiles that naturally increase resistant starch often led to smaller grains and lower harvests through mechanisms that are not entirely clear.

Against this backdrop, a research team led by Dr. Guozhang Kang and Dr. Gezi Li from Henan Agricultural University, China, have made a discovery that could reshape the future of wheat genetic engineering. Their study, published in The Crop Journal on November 8, 2025, identified a gene that plays a major role in the yield–quality trade-off.     

The team focused their investigation on the Jasmonate ZIM-domain (JAZ) proteins, a family of transcriptional repressors primarily known for their role in helping plants respond to stress. By conducting a genome-wide association study, the team identified a specific JAZ gene, designated TaJAZ1, that was highly expressed during the grain-filling stage, suggesting a strong involvement in starch accumulation.

To understand its precise function, the researchers employed the CRISPR/Cas9 gene-editing system to create two targeted knockout mutant lines. Simply put, they used guided molecular scissors to make the TaJAZ1 gene non-functional in these plants.

Notably, deactivating this gene led to a synergistic improvement across important traits. Compared to standard wild-type wheat, the two mutant lines exhibited substantial increases in single-grain weight and overall yield per plant. Moreover, this boost in overall production was also accompanied by an increase in resistant starch content, which nearly doubled.

The research team also explored the molecular mechanisms behind these gains. After a series of in-depth experiments, they concluded that TaJAZ1 acts as a bidirectional regulator in grains that represses key enzymes responsible for making starch, as well as affecting the final starch’s composition and structure.

“Taken together, our findings reveal that JAZ proteins are master transcriptional regulators of carbon partitioning in grains,” says Dr. Kang, “They provide a genetic tool for improving the yield–quality balance and enables the breeding of wheat cultivars with enhanced productivity, processing quality, and health benefits.”

“In 5 to 10 years, our research could lead to the development of new wheat varieties combining high yield, high resistant starch content, and low glycemic index, to help people improve metabolic health through their daily diet. This could especially benefit individuals with diabetes or obesity,” concludes Dr. Li.

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