Seeding a New Green Revolution

Researchers at the University of Oxford and the Chinese Academy of Sciences discover a new gene which improves yields of cereal crops such as wheat and rice, using less fertilizer.

“Elite crops” can be grown to maintain their current high yields with less fertilizer, according to a paper published online this week in Nature.

The new study led by Professor Xiangdong Fu from the Chinese Academy of Sciences, Institute of Genetics and Developmental Biology, Beijing, and Professor Nicholas Harberd from the Department of Plant Sciences at the University of Oxford, and part-funded by the BBSRC-Newton Fund Rice Initiative, have discovered a gene with the potential to reach sustainable global food security by understanding of how plants metabolize nitrogen.

The worldwide “Green Revolution” began in the 1960s and saw yearly increases in global cereal grain yields. The revolution was fuelled by the development of new high-yielding dwarfed varieties of cereal, known as Green Revolution Varieties or GRVs. These dwarfed varieties still dominate today’s wheat and rice crops. Because they are dwarfed they have shorter stems, and give relatively greater yields than the taller plants they replaced. They are also less susceptible to yield-losses from wind and rain damage.

But the growth of GRVs requires farmers to use large amounts of nitrogen-containing fertilizers on their fields. These fertilizers are costly to farmers, and cause extensive damage to the natural environment. The crops themselves are less efficient at using nitrogen — a side effect of a growth-inhibiting protein called DELLA.  This means farmers must apply high doses of environmentally unfriendly, nitrogen-based fertilizers to compensate.

The researchers in this project compared 36 different dwarfed rice varieties and identified a new natural gene variant that increases the rate plants incorporate nitrogen from the soil. The discovered gene variant increases the amount of a protein called GRF4 in plant cells. GRF4 stimulates the activity of other genes, promoting nitrogen uptake and increasing the yield.

“We reasoned that tipping the GRF4-DELLA balance in favor of GRF4 might reduce the need for high fertilizer levels in GRV cultivation,” said Professor Harberd. “And to our delight, we found that increasing GRF4 levels caused an increase in the grain yields of both rice and wheat GRVs, especially at low fertilizer input levels.”

The Newton Fund’s Sustainable Rice Programme is an innovative mix of regional and country approaches addressing core challenges for global and regional food security in a changing climate and developing resilience to crop pests and diseases.

For more information on the Sustainable Rice Programme, visit here: BBSRC: UK researchers to lead UK-China-Thailand-Philippines-Vietnam partnership of crucial research to underpin the long-term sustainable future of rice.

For the scientific paper in online version, please see: Nature: Modulating plant growth–metabolism coordination for sustainable agriculture

(Source: BBSRC)