Rice Gene WRINKLED1a Boosts Yields by 24% While Cutting Fertilizer Dependence

Nitrogen fertilizer built the modern food system. It also strains it. Producing synthetic nitrogen requires enormous energy, and its application to fields contributes to greenhouse gas emissions, contaminates waterways, and degrades soil over time. Rice alone - the staple crop for over half of the world's population - consumes vast quantities of nitrogen fertilizer each growing season, making it a natural focus for researchers trying to decouple crop productivity from chemical inputs.

The fundamental problem is biological. When plants sense low nitrogen in the soil, they divert resources from shoots toward roots, putting more tissue underground to forage for nutrients. That shift makes adaptive sense in the wild but is precisely wrong for agriculture, where grain yield depends on robust shoot development. For decades, the molecular switch controlling this trade-off remained unidentified.

A research collaboration spanning the University of Oxford, Nanjing Agricultural University, and the Institute of Genetics and Developmental Biology at the Chinese Academy of Sciences has now found it. The gene is called WRINKLED1a, and manipulating it in rice produces plants that maintain shoot growth and yield even when nitrogen is scarce - without the typical sacrifice of root development.

What WRINKLED1a Does Differently in Roots and Shoots

The researchers began by generating rice plants lacking a functional copy of WRINKLED1a. These plants lost the ability to prioritize root growth under low-nitrogen conditions and showed reduced shoot growth when nitrogen was abundant - confirming the gene's role as a central regulator. In the opposite experiment, plants engineered to overexpress WRINKLED1a showed stronger growth in both roots and shoots and maintained a more stable root-to-shoot ratio as external nitrogen levels varied.

The mechanism turns out to be tissue-specific. In shoots, WRINKLED1a acts as an activator, switching on NGR5, a key regulatory gene that promotes shoot branching. In roots, it activates genes involved with nitrogen uptake and disrupts a protein complex that normally suppresses the accumulation of auxin - the plant hormone that promotes root growth. Crucially, WRINKLED1a does not disrupt that same protein complex in the shoot, so the root-promoting and shoot-promoting effects do not cancel each other out.

From Greenhouse to Field

Laboratory results that do not survive field conditions are common in crop science. This work includes three field trials, conducted in Hainan and Anhui provinces, China, that tested a practical strategy: screening existing rice diversity for a naturally stronger version of the gene.

The team screened more than 3,000 rice cultivars and identified a natural variant of WRINKLED1a that is expressed more strongly than the common form. They crossed this stronger allele into plants carrying a weaker version, then grew the resulting lines under both low and high fertilizer regimes across multiple growing seasons.

The results were consistent. At low nitrogen fertilizer application (120 kg per hectare), the improved allele raised yields by 23.7% compared to control plants. At high fertilizer input (300 kg per hectare), the gain was 19.9%. The plants with the stronger allele maintained a more stable root-to-shoot ratio across different nitrogen conditions - they were not simply throwing more resources at shoots at the expense of root function, but achieving better balance across varying nutrient availability.

The Broader Stakes

Global rice harvests face compounding threats. Studies indicate that every 1 degree Celsius rise during the rice-growing season can reduce yields by more than 8%, and nitrogen fertilizer costs can account for roughly a third of total production costs for some farmers. A gene variant that maintains yields at lower fertilizer input addresses both the economic and environmental dimensions of the problem simultaneously.

Lead author Dr. Shan Li noted that the next step is investigating whether homologous versions of WRINKLED1a in wheat and maize could achieve similar outcomes, since the gene's function may be conserved across cereal crops.

The study does carry limitations worth noting. The field trials were conducted in two specific provinces in China under conditions that may not represent the full range of soils, climates, and farming systems where rice is grown. The 23.7% yield increase is a meaningful result, but performance across different rice varieties, geographies, and growing conditions will need additional evaluation before the finding translates into broadly applicable agronomic guidance. Regulatory approvals for gene-modified or gene-selected varieties also vary by country, adding another layer of complexity to practical deployment.

The research was published in Science on February 26, 2026.