Dynamic changes of phenolic compounds during artificial aging of soybean seeds identified by high-performance liquid chromatography coupled with transcript analysis

Phenolic compounds are important bioactive substances in plants, but study of their alteration during soybean seed aging is still limited. In this study, we conducted artificial aging on soybean seeds, detected the dynamic changes of phenolic compound concentrations using high-performance liquid chromatography, and analyzed the gene expression of key enzymes of phenolic metabolism. A detailed method for detection of 19 phenolic compounds during artificial aging of soybean seeds was constructed, and all of these phenols significantly changed in concentration. The content of protocatechuic acid, rutin, and morin decreased, whereas that of daidzein, glycitein, genistein, and baicalin increased. The concentration of caffeic acid, epicatechin, ferulic acid, daidzin, genistin, and resveratrol first rose and then declined, and the content of ferulic acid was highest after 2 days of artificial aging, with the other five phenolic compounds showing the highest content after 4 days of artificial aging. The total content of the 19 phenolic compounds reached a peak of 2357.43 μg g-1 dry weight at 2 days. Relative expression of PAL1, PAL2, PAL3, CHS7, CHS8, IFS1, IFS2, CHR1, 4CL2, C4H, and CHI2 was mostly downregulated as the duration of artificial aging increased. This study provides novel insights into the storage and use of soybean seed resources.