Relying on domestic self-breeding varieties of wheat, the sown area has decreased but the yield has increased greatly
Series Reports on Food Breeding Technology ③
Our reporter Ma Aiping
Hybrid wheat is the only undeveloped hybrid seed industry for major food crops in the world. It has a huge industrial potential. It is expected to create a market value of 30-50 billion yuan each year, and the domestic market can reach 3 billion-50 billion yuan each year, which can be reduced every year. Irrigation is about 1 billion cubic meters, reducing economic investment by about 1 billion.
Zhao Changping, Researcher of Beijing Academy of Agriculture and Forestry Sciences, Director of Beijing Hybrid Wheat Engineering Technology Research Center
my country is the world's largest producer and consumer of wheat.
A set of data recently released by the Chinese Academy of Agricultural Sciences shows that the sown area of wheat in my country in 2020 will be reduced by 27 million mu compared with 2011, but the output will increase by 13 million tons.
"Behind one decrease and one increase is the power of science and technology." said Wan Jianmin, vice president of the Chinese Academy of Agricultural Sciences and academician of the Chinese Academy of Engineering. It is a major scientific research task to bred a batch of new wheat varieties with internationally leading levels, and all wheat varieties in my country are domestically bred, which means that they do not rely on imports.
The “Thirteenth Five-Year” national key research and development plan “seven major crop breeding” key special projects, bred a wide-adapted high-yield and stable-yield new wheat variety "Luyuan 502" and a new super-gluten, early-maturing and disease-resistant wheat variety "Jimai 44", the former being continuous It has been listed as a leading variety by the Ministry of Agriculture and Rural Affairs and the provincial level for many years, with a yield of more than 800 kg per mu, and a total of 57.385 million mu of planting. The latter received 15 million yuan in variety transfer income, a national record.
Cloning of key genes for resistance to scab
In the past five years, genomics research on major crops in my country has made rapid progress, and a series of forward-looking, leading, and original breakthroughs have been made in basic research fields such as in-depth analysis of genome structural variation, genome evolution rules, and key agronomic trait gene cloning.
In the field of wheat, the drawing of a fine map of the D genome at the level of wheat chromosomes was completed; the wheat Taigu nuclear sterile gene Ms2 and the scab resistance genes Fhb1 and Fhb7 were cloned, which greatly improved the efficiency of wheat breeding.
On June 10, 2019, "Nature Genetics" published online a research paper by the team of Professor Ma Zhengqiang of Nanjing Agricultural University.
The paper reported an extremely important scab resistance gene Fhb1 in wheat, which laid an important foundation for further revealing the molecular mechanism of wheat scab resistance.
The cloning of wheat scab resistance gene Fhb1 provides valuable genes and molecular markers for the cultivation of scab resistance wheat.
Scientists in my country have bred 37 wheat lines resistant to head blight, and these lines have been distributed to 58 breeding units nationwide free of charge. Six of the selected lines have entered pre-test or regional testing, and one line has entered the stage of promotion and application. Huge potential for promotion and application.
In April 2020, "Science" magazine published online research results of the team of Professor Kong Lingrang, Professor of Agricultural College of Shandong Agricultural University and Chief Expert of the Wheat Innovation Team of Shandong Modern Agricultural Industrial Technology System. They cloned the research results from the wheat relative plant Elytrigia Fhb7, the main gene for head blight resistance, reveals its molecular mechanism of disease resistance; germplasm materials carrying this gene have been used in wheat breeding by many companies, showing stable resistance to head blight.
There are five major innovations in the research results: cloned the Fhb7 anti-head blight gene; discovered that the enzyme encoded by the Fhb7 gene has a detoxification function for vomiting toxin; provided functional evidence for the horizontal transfer of nuclear genomic DNA between eukaryotes; assembled long ears Elytrigia genome; Fhb7 gene was found to have broad-spectrum resistance to the entire Fusarium pathogen.
"Through a series of molecular experiments and high-resolution mass spectrometry analysis, we found that the protein encoded by Fhb7 can open the epoxy group of vomiting toxin and catalyze the formation of glutathione adducts, thereby producing a detoxification effect. Stable resistance and application value in wheat breeding for disease resistance." Kong Lingrang told reporters that wheat with head blight can produce vomiting toxins, and vomiting toxins will seriously contaminate food and feed, which is determined by the World Health Organization as naturally occurring. Extremely dangerous food contaminants can cause human and animal poisoning.
At the same time, vomiting toxin can accumulate in humans and mammals, and induce chronic side effects such as decreased immune function.
Directional creation of new wheat germplasm
Genome editing technology is an effective means to create breakthrough germplasm resources and accelerate the breeding process.
At present, gene editing technology mediated by the CRISPR/Cas9 system has been widely used in crop functional genomics research and crop genetic breeding improvement. However, because wheat is heterohexaploid, the genome is relatively large and the background is complex, the efficiency of genetic transformation is relatively high. Low, there is still a lack of efficient wheat multi-gene editing system.
In response to these problems, the wheat molecular breeding team of the Crop Research Institute of Shandong Academy of Agricultural Sciences has developed an efficient wheat multi-gene multi-target editing technology system through the optimization and modification of vector elements.
The team’s paper published in the Journal of Plant Biotechnology in November 2020 shows that they have systematically optimized wheat gene editing vector components and constructed three ribozyme systems for wheat multi-gene editing vectors that can target A, 8 sites on the B and D genomes.
The new technology system enables the simultaneous editing efficiency of single gene and three targets in wheat to reach 100%, the simultaneous editing efficiency of double genes and six targets to 96%, and the simultaneous editing efficiency of three genes and eight targets to 37%.
The results of this study indicate that my country's wheat gene editing efficiency has reached the international leading level.
Just recently, Chinese scientists have made another breakthrough in the breeding research of wheat multi-gene editing technology.
According to news from the Chinese Academy of Agricultural Sciences on April 9th, scientists from the Institute of Crop Science of the Academy published a research paper online in Molecular Plants, saying that they used multi-gene editing technology to achieve the aggregation of multiple excellent alleles of the first generation of winter wheat and succeeded A new wheat germplasm without the introduction of foreign genes was obtained.
Team member Xia Lanqin introduced that they used the CRISPR/Cas9 system to develop an efficient and versatile multi-gene editing technology.
The team used the wheat variety "Zhengmai 7698" grown on a large area in the Huanghuai wheat area as the recipient material, and used the new technology to simultaneously edit 15 genomic loci, and obtained 2, 3, 4, and 5 gene-edited plants respectively. , The highest editing efficiency can reach 50%.
Without the need to introduce foreign genes, the team successfully obtained a new wheat germplasm that aggregates multiple excellent alleles.
The establishment of this high-efficiency and universal multi-gene editing system will help promote the analysis of wheat molecular biology research and the formation of complex traits, create targeted new wheat germplasm, accelerate the breeding process, and develop for wheat and other polyploid crops. Multi-gene polymerization breeding provides important technical support.
Lay the foundation for hybrid wheat seed production
Hybrid wheat is considered to be one of the first choices for a substantial increase in global wheat production in the future.
It is predicted that if the promotion and application of hybrid wheat reaches the same level as hybrid rice, my country can increase its annual wheat output by about 12 million tons (calculated based on China’s total annual wheat output of 120 million tons and a 10% increase in output), which will have a significant impact on ensuring national food security. Significantly.
However, wheat, which is also one of the three major food crops in the world, was limited by the complexity of its genome and stalled in hybrid breeding.
The high cost of seed production also greatly restricts the industrialization of hybrid wheat.
"Hybrid wheat is the only undeveloped hybrid seed industry for major food crops in the world. It has a huge industrial potential. It is estimated that it can create a market value of 30-50 billion yuan each year, and the domestic market can reach 3 billion-50 billion yuan each year. Reduce irrigation by about 1 billion cubic meters and reduce economic investment by about 1 billion yuan." Zhao Changping, a researcher at the Beijing Academy of Agriculture and Forestry Sciences, director of the Beijing Hybrid Wheat Engineering Technology Research Center, and chief expert, told reporters.
During the "Thirteenth Five-Year Plan" period, important progress has been made in basic research on hybrid wheat in Beijing: Scientists from Beijing Academy of Agriculture and Forestry Science cloned the first major gene TaTMS1 for temperature-sensitive male sterility in wheat for the first time in the world, providing a theory for the construction of hybrid wheat system in China Basis: 6 hybrid wheat varieties have been certified, achieving a "zero" breakthrough in the core main wheat-producing regions for certified varieties and a "zero" breakthrough in foreign certified varieties.
"Common wheat is a strictly dioecious, self-pollinated crop. Finding genetic resources for male sterility is an important way to realize the utilization of wheat heterosis. Based on the discovery of the phenomenon of light-temperature-sensitive male sterility in wheat, Chinese wheat scientists have been independent from China In some BS series of wheat photo-thermo-sensitive male sterile germplasm, the first wheat thermo-sensitive male sterility major gene TaTMS1 was discovered and cloned for the first time, and it was found that its promoter had a key base variation, which caused TaSL1 to activate TaTMS1. The enhanced proton binding can reduce the expression of TaTMS1 at low temperatures; disrupting the interaction between TaTMS1 and the TaATP1 oxidation zone in the inner layer of anther chloroplasts can lead to disturbances in energy supply and the production of large amounts of reactive oxygen species, ultimately leading to male sterility." Beijing Academy of Agriculture and Forestry Hybridization Zhang Shengquan, an associate researcher of the Wheat Center, said that the cloning of wheat male sterility genes has laid the foundation for the construction of stable, efficient, and large-scale hybrid wheat seed production technology, and also for the construction of China's hybrid wheat system and the successful use of sterile lines to achieve great wheat heterosis. The area application provides support.