Summary of Key Findings
A team of Chinese scientists has published an important research achievement in the journal *Nature*: They have successfully cloned the second high-protein gene, THP3-T, which was previously “lost” during the domestication of wild corn. When combined with the THP9-T gene discovered in 2022, this gene can increase the protein content in commonly cultivated corn varieties from around 8% to 12%-13% (in the grain) and over 9% (in the entire plant), while maintaining stable yields. This breakthrough could significantly reduce China’s dependence on imported soybean meal (currently, more than 80% of feed protein is sourced abroad). It would also boost farmers’ incomes and reshape the feed protein supply chain. However, it will still take several years before these findings can be widely applied in practical farming.
Detailed Analysis
1. Solving a Critical Issue for China’s Feed Industry
Corn is the most widely produced crop in China, with an annual output of 300 million tons. However, its main drawback is the low protein content in the grain, which is only around 8%, far from meeting the nutritional needs of livestock and poultry farming. To address this gap, China imports 100 million tons of soybeans annually to produce soybean meal, resulting in a high dependence on foreign feed proteins—essentially, China’s livestock and poultry feed supply is “held hostage” by other countries. In contrast, wild corn (Zea mays) contains up to 30% protein, four times that of modern corn. For thousands of years, breeders have focused on increasing yield, inadvertently eliminating these high-protein genes. By restoring the THP3-T and THP9-T genes, corn can produce more protein on its own, eliminating the need for expensive imports.
2. The Synergy of Two Genes: One Produces, One Distributes
The combined effect of these two genes functions like a “dual-engine system”:
- THP3-T (Production Engine): This gene encodes an enzyme that converts nitrogen from the soil (a key fertilizer nutrient) into amino acids, the building blocks of protein. It acts as the “factory” for producing protein.
- THP9-T (Distribution Engine): This gene encodes an enzyme that transports the produced amino acids to the corn grains, allowing them to accumulate more protein and reducing nutrient waste in the stalks. Field trials have shown that introducing these genes into the popular Chinese corn variety “Zhengdan 958” increased protein content without reducing yield, ensuring both higher farmer incomes and better feed quality.
3. Benefits for the Entire Supply Chain
- Farmers: High-protein corn commands a higher purchase price of 200 yuan per ton compared to regular corn, leading to increased income with large-scale cultivation.
- Livestock Farmers: High-protein corn contains more and more easily digestible amino acids. It can replace 50%-100% of soybean meal when feeding pigs for fattening, and reduce the need for soybean meal in egg and meat chicken feed, lowering feed costs.
- Government: If the protein content in China’s 300 million tons of corn is increased by 4 percentage points (to over 12%), the additional protein would be equivalent to 30 million tons of imported soybeans, significantly reducing the country’s reliance on foreign imports.
4. From Laboratory to Field: Several Hurdles to Overcome
The current findings are still in the laboratory phase. Before becoming commercially available, several steps need to be taken:
- Hybrid Selection: Cross the improved genes with other varieties to develop combinations that are high in protein and adaptable to different climates.
- Multi-Environment Testing: Conduct trials in major corn-producing regions such as Northeast China, North China, and Southwest China to ensure stable high yields under various soil and weather conditions.
- Corporate Collaboration: Work with seed companies to bring the new varieties to market.
- Further Gene Discovery: The team plans to identify more high-protein genes to further increase corn protein content to 15%. This process will take at least several years, but the direction is clear.
Conclusion
The discovery of these genes is not just a theoretical achievement; it represents a breakthrough technology that can genuinely transform China’s feed industry. It addresses the issue of import dependence and benefits both farmers and livestock producers. Although we still need to wait for several years before widespread adoption, this is a crucial step toward making China’s livestock and poultry feed more self-sufficient and affordable.