Wheat breeders have long struggled to raise yields without compromising nutritional quality. A new study from China points to TaJAZ1 as a central gene driving this long-standing trade-off. By using CRISPR to deactivate TaJAZ1, researchers produced wheat lines with sharply higher grain yield and almost double the resistant starch content. The results offer a promising genetic approach to developing wheat varieties that are both more productive and healthier — supporting future food security and improved metabolic health.
As climate change and population growth intensify global pressure on food systems, wheat remains one of the most important staple crops for ensuring food security. Wheat grain provides a large share of calories worldwide and contains roughly 70% starch. The amount and type of starch influence not only how wheat is processed, but also its nutritional value. For decades, breeders have aimed to deliver wheat that combines high productivity with better nutritional quality — but achieving both has proven difficult.
This challenge stems from the fact that yield and starch traits are controlled by multiple interacting genes and proteins. One particularly desirable trait is resistant starch, which behaves like dietary fiber by resisting digestion in the small intestine and supporting healthier glucose metabolism. However, wheat varieties that naturally accumulate more resistant starch often produce smaller grains and reduced yields, and the mechanisms behind this have remained unclear, according to a press release.
Researchers led by Dr. Guozhang Kang and Dr. Gezi Li at Henan Agricultural University have now identified a potential breakthrough. Their study, published in The Crop Journal on November 8, 2025, highlights TaJAZ1 as a key genetic factor influencing the yield–quality relationship.
The team investigated the Jasmonate ZIM-domain (JAZ) protein family, which is best known for regulating plant stress responses. Through a genome-wide association study, they pinpointed TaJAZ1 as a strong candidate because it is highly active during the grain-filling stage, when starch accumulation is critical.
To confirm the gene’s role, the researchers used CRISPR/Cas9 to generate two knockout wheat lines by disabling TaJAZ1. Removing the gene delivered gains across multiple traits at once: the edited plants produced heavier grains and significantly higher yield per plant, while also showing a striking rise in resistant starch — nearly doubling compared to wild-type wheat.
Further molecular analysis suggested that TaJAZ1 functions as a bidirectional regulator in developing grains. It suppresses key enzymes involved in starch synthesis and also influences starch composition and structure — helping explain why switching off the gene can improve both yield and nutritional quality simultaneously.
“Taken together, our findings reveal that JAZ proteins are master transcriptional regulators of carbon partitioning in grains,” says 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 five 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 Li.
