Flavonoid localization in soybean seeds: Comparative analysis of wild (Glycine soja) and cultivated (Glycine max) varieties.

Wild soybean (Glycine soja) is known for its high flavonoid contents, yet the distribution of flavonoids in the seeds is not well understood. Herein, we utilized matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) and metabolomics methods to systematically investigate flavonoid differences in the seed coats and embryos of G. soja and G. max. The results of flavonoid profiles and total flavonoid content analyses revealed that flavonoid diversity and abundance in G. soja seed coats were significantly higher than those in G. max whereas the levels were similar in embryos. Specifically, 23 unique flavonoids were identified in the seed coats of G. soja , including procyanidins, epicatechin derivatives, and isoflavones. Using MALDI-MSI, we further delineated the distribution of the important flavonoids in the cotyledons, hypocotyls, and radicles of the two species. These findings imply that G. soja holds considerable breeding potential to enhance the nutritional and stress resistance traits of G. max. • MALDI-MSI was used for the first time to reveal the distinct distribution patterns of flavonoids in the wild and cultivated soybean seeds. • Compared with cultivated soybeans, flavonoid diversity and abundance in wild soybean seed coats were significantly higher, but similar in embryos. • This study underscores the potential nutritional and breeding value of wild soybean as a reservoir of flavonoid-rich germplasm. [ABSTRACT FROM AUTHOR]