Open-field warming regulates the morphological structure, protein synthesis of grain and affects the appearance quality of rice

Due to the sensitivity of chalk formation to high temperatures, the global warming will further threaten the improvement of high chalky grain rate in the southern japonica region of China. There have been many studies reported on the role of starch in the formation of chalkiness, but the relationship between nitrogen metabolites and chalkiness has not been given sufficient attention. In this study, we conducted the open field warming experiment and investigated the effects of temperature increase on grain protein metabolism. Results showed under the warming range of predicted global temperature increase (1.9 °C-4.0 °C), field warming apparently accelerated the development of grain endosperm, and the number of protein bodies were increased in both rice varieties, Furthermore, we clarified that the increased temperature regulated the key regulatory factors in protein synthesis and metabolism pathway, and the synthesis, transport, folding, assembly process of grain protein were further affected, and that further lead the component changes of grain storage protein. In conclusion, chalky traits are closely related to the grain storage materials and in this study, increased temperature induced the changes in the accumulation balance of storage proteins, amino acids and starches, which coordinately controls the formation of grain chalkiness.