Effect of Harvest Time on Non-Volatile Metabolites in Japonica Rice

A large number of non-volatile metabolites are produced during the growth of rice; however, few studies have focused on the changes in these metabolites at different harvest times. In this study, Nangeng 5718 (a rice variety) was taken as the research object to study the changes in rice metabolites at different harvest times. Liquid chromatography mass spectrometry (LC-MS) was used to analyze the non-targeted metabolomics of rice at different harvest times in Nanjing, Huai'an, and Lianyungang in the Jiangsu Province of China. The results showed that 2111 metabolites were annotated by the human metabolome database (HMDB), accounting for 94.96% of the total number of metabolites. Rice metabolites included one categories, including 312 fatty acyls, 275 organooxygen compounds, 261 carboxylic acids and derivatives, etc. The results of the Kyoto encyclopedia of genes and genomes (KEGG) pathway showed that autophagy-other, ABC transporters, and glycerophospholipid metabolism had a great effect on rice heading to harvest. The experiments showed that L-histidine in Nangeng 5718 was upregulated. These results provide comprehensive insights into the relationship between rice harvest time and changes in metabolites.