Metabolomics reveals the defense mechanism of different rice under space flight stress

Abstract

BackgroundSpace flight is a special abiotic stress condition. Due to the development of space technology, its potential value has received widespread attention. Space mutation breeding is one of the important methods for human beings to solve food security. However, the molecular mechanism of space mutagenesis is still not very clear.ResultIn this study, two kinds of rice, Dongnong423 (DN3) and Dongnong416 (DN6), were carried on the SJ-10 retractable satellite for 12.5 days in orbit, returned to the ground and planted in the field until the three-leaf (TLP) and tillering stage (TS). The results of antioxidant enzyme activity, soluble sugar, and electron leakage rate revealed that the space environment caused the stress response of rice. The TLP and TS of DN3 identified 113 and 58 different metabolites, respectively. The TLP and TS of DN6 identified 107 and 77 different metabolites, respectively. These metabolites include amino acids, sugars, fatty acids, organic acids and secondary metabolites. We used qRT-PCR technology to explore the changes of enzyme genes in the TCA cycle and amino acid metabolism pathway. Combined with the results of metabolomics, we determined that during the TLP, the TCA cycle rate of DN3 was inhibited and amino acid metabolism was activated, while the TCA cycle rate of DN6 was activated and amino acid metabolism was inhibited. In TS, the TCA cycle rate of DN3 was inhibited, and amino acid metabolism was not significantly changed, while the TCA cycle rate of DN6 was activated and amino acid metabolism was inhibited. These results suggest that the space environment has different stress response mechanisms to the two rice varieties, and these differences may be reflected in energy consumption and compound biosynthesis.ConclusionsThis research uses metabolomics for the first time to explore the effects of space flight team rice. This research provides new insights for further exploring the effects of space biology and space mutation breeding.