After ten years of unremitting efforts, the Molecular Plant Science Excellence and Innovation Center of the Chinese Academy of Sciences and the scientific research team of Shanghai Normal University successfully cloned the high protein gene THP9 from wild corn for the first time, and effectively improved the protein content of modern corn through hybridization experiments. This achievement was published online today (17 days) in the international academic journal Nature. The ancestors of corn originated in South America, called big ruminant grass. The seeds are wrapped with hard shells and cannot be eaten directly. Human ancestors began to domesticate corn 9000 years ago, and gradually transformed the weed like wild corn into today's corn. The researchers found that the seed protein content of wild maize was as high as 30% without nitrogen fertilizer, which was three times that of modern common cultivated maize, indicating that wild maize contained key genes to control high protein content. Over the past decade, the research team has extracted more than 40000 samples of DNA for identification, and finally cloned the first major gene controlling high protein content in maize from wild maize. Wu Yongrui, a researcher at the Center for Excellence and Innovation in Molecular Plant Science of the Chinese Academy of Sciences, said that corn has become one of the most productive crops in the world. 70% of corn is used as feed, which is the most commonly used and used feed. Due to the low protein content of ordinary corn grains, soybean protein needs to be supplemented in the feed. However, soybean is heavily dependent on imports, which has become a "choke" problem in China's livestock and poultry breeding industry. If the content of ordinary corn protein increases by one percentage point, it is equivalent to that more than 7 million tons of soybeans can be imported less each year. The research team conducted a large-scale field experiment in Sanya, and introduced the wild maize high protein gene Thp9-T cross into Zhengdan 958, a maize production and cultivation variety with the largest promotion area in China, which can significantly improve the protein content, indicating that this gene has important application potential in cultivating high protein maize. At the same time, under the condition of reducing the application of nitrogen fertilizer, it can effectively maintain the biomass of maize and the level of nitrogen content in plants and grains, which is of great significance for reducing the use of chemical fertilizers and protecting the ecological environment. (Liu Xinshe)