Through research, the Chu Chengcai team and Gao Caixia team of the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences have recently found two "switches" that regulate rice and wheat pre harvest sprouting, including SD6, a key gene that negatively regulates seed dormancy, and ICE2, a gene that positively regulates seed dormancy. The researchers believe that the combination of the two genes is expected to provide a solution to the large-scale agricultural loss caused by the pre harvest germination of seeds. This achievement was published online in Nature Genetics on December 6. In the process of crop domestication, due to more consideration of high yield, good quality, disease and insect resistance and stress tolerance, the retention of moderate dormancy of seeds is often neglected, which leads to the phenomenon of sprouting of many crops, such as rice and wheat (if the seeds cannot be harvested in time during the ripening period before harvest, part of the seeds often sprout on the ears), which seriously affects the yield and quality of crops and causes huge economic losses, It even affects sowing in the next season. Therefore, it is very important to find the key genes controlling seed dormancy such as rice and wheat, clarify the molecular physiological mechanism of seed dormancy regulation, and dig out its excellent allelic variation to solve the disaster of rice and other crops' pre harvest germination. The scientific research team of the Institute of Genetics and Development of the Chinese Academy of Sciences successfully cloned a key gene SD6 that controls rice seed dormancy from a strong dormancy rice variety by using the strong dormancy rice variety Kassalas and the weak dormancy rice variety Nippon Qing to construct a chromosome single segment substitution line, and confirmed that SD6 negatively regulates rice seed dormancy. By screening SD6 interacting proteins, the research team found another rice transcription factor, ICE2, which is regulating seed dormancy. The research team found that the SD6/ICE2 molecular module is a seed dormancy regulator that can sense the ambient temperature: under normal temperature conditions, SD6 gene expression maintains a high level to play its role, while ICE2 gene function is significantly inhibited, thus promoting seed germination; Under low temperature, SD6 gene function was significantly inhibited, and ICE2 gene expression was up-regulated, which played a role in maintaining seed dormancy. That is to say, SD6/ICE2 increases and decreases by sensing the change of external environment temperature, further controlling the content of plant hormone abscisic acid in seeds, so as to regulate the dormancy intensity of seeds, ensure that they adapt to the change of natural seasons and reproduce successfully. The research team improved the SD6 gene in Tianlong 619, Wuyunjing 27 and Huaidao 5, which are easy to sprout in rice, through gene editing technology. It was found that the improved rice materials encountered continuous rainy weather during the harvest period, and their pre harvest germination was significantly improved. The research team improved the TaSD6 gene of wheat variety Kenong 199, which can also greatly improve the resistance to pre harvest sprouting of wheat, indicating that the SD6 gene is conservative in controlling seed dormancy in rice and wheat. All these research results show that SD6 has important application value in breeding improvement of rice and wheat for pre harvest sprouting resistance. (Liu Xinshe)
Edit：Ying Ying Responsible editor：Wang Chen
Source：cctv.com
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