Scientists have successfully cloned high-temperature genes to promote high-temperature research and development of rice

The research team led by Academician Lin Hongxuan, the State Key Laboratory of Plant Molecular Genetics of the Institute of Plant Physiology and Ecology of the Chinese Academy of Sciences Shanghai Academy of Sciences, has made important progress in functional genomics research in rice. They successfully cloned the control of high temperature resistance from crops for the first time. Quantitative Trait Loci (QTLs) and their in-depth study of their molecular mechanisms, their role in rice evolution and resistance to high-temperature breeding, and related research published online May 18, 2015 in the journal Nature Genetics ("Natural Genetics").

With the global climate change, extreme high-temperature weather has appeared more and more frequently, posing a serious threat to food production. Rice as a staple food for more than half of the world's population, the stability of its output has also been a serious threat to high temperatures. Therefore, it is of great strategic significance to explore the heat-resistance gene resources of crops and then develop new varieties of high-temperature resistance to cope with the threat of climate warming. However, because the high temperature resistance of crops is a complex trait controlled by multiple QTL loci, the research is difficult, and the work of excavating and cloning high-temperature genes in crops is challenging. There have been no previous reports of successful isolation of cloned crops resistant to high-temperature QTL genes.

Lin Hongxuan and others began to pay attention to the study of crop heat resistance over 10 years ago. After long-term efforts, under his guidance, doctoral student Li Xinmin successfully cloned and cloned the main effect QTL, the high-temperature resistance gene (TT1), which controls high temperature resistance in rice in Africa. They further studied the molecular mechanisms underlying the regulation of high temperature resistance in rice by the gene. The results showed that when rice is exposed to high temperature stress, its intracellular proteins are largely inactivated and denatured. These denatured proteins, like garbage in urban areas, not only cannot function normally, but are toxic, affecting normal cells. Life activities, in severe cases, will cause the cells to rupture and die, and the rice plants will wither and die. The study found that the gene (TT1) derived from the African rice can rapidly initiate response at a high temperature and participate in the "sanitation system" of degrading denatured proteins in cells so that the plant cells can remove these toxic substances in time and effectively. "To prevent excessive accumulation of them to cause cell necrosis, thereby enhancing the heat resistance of plants."

In Asia, cultivated rice is cultivated in China, and African rice is a species different from Asian rice. It grew on the tropical continent of Africa tens of thousands of years ago, and evolved independently of Asian rice. Population genetic analysis showed that although African rice has evolved a specific form of TT1 gene, it can adapt to tropical high temperature environment; in fact, the rice varieties cultivated in China also have the “sister gene” of the gene, but its high temperature resistance Relatively weak. Moreover, further studies have found that the resistance to high temperatures of the TT1 “sister genes” in these different breeds varies from country to country: In general, breeds growing in low latitudes are resistant to the higher temperature of the environment they face. The high temperature capability is slightly stronger; on the contrary, the high temperature resistance of the gene in the high latitude region is weak. It can be seen that the TT1 “sister gene” locus has already played a role in adapting them to environmental temperature during the process of cultivating modern rice varieties, and is a genetically important genetic locus.

The African rice is considered to be a precious genetic resource pool to be developed. Many international institutions and research groups are trying to discover the resources of the anti-stress genes in the African rice genome. TT1 is an important gene that has been pioneered in these efforts and has provided valuable genetic resources for crop improvement. Through years of field crosses, the study introduced the high temperature-tolerant TT1 gene of African rice into China's cultivated rice varieties, which significantly enhanced the high temperature resistance of the variety; meanwhile, it also explored the TT1 in turfgrass and cross-flowers. The high temperature-resistance effect in plants such as families shows that it has the function of increasing the high-temperature tolerance of plants in different species. These findings also suggest that TT1 has a wide range of potential applications in crop breeding such as wheat and other cruciferous vegetables such as Chinese cabbage.