Metabolic Profiling of a Fast Neutron Soybean Mutant Reveals an Increased Abundance of Isoflavones

A total of 718 metabolites were identified in leavesand seedsof the soybean (Glycine max (L.) Merr.,Fabaceae) fast neutron (FN) mutant 2012CM7F040p05ar154bMN15, whichwas previously shown to have 21 genes deleted and higher protein contentin seeds as compared to wild-type. Among the identified metabolites,164 were found only in seeds, 89 only in leaves, and 465 in both leavesand seeds. Metabolites that exhibited higher abundance in the mutantleaf than in the wild type include the flavonoids afromosin, biochaninA, dihydrodaidzein, and apigenin. Mutant leaves also exhibited a higheraccumulation of glycitein-glucoside, dihydrokaempferol, and pipecolate.The seed-only metabolites that were found in higher abundance in themutant compared to the wild type included 3-hydroxybenzoate, 3-aminoisobutyrate,coenzyme A, N-acetyl-& beta;-alanine, and 1-methylhistidine.Among several amino acids, the cysteine content increased in the mutantleaf and seed when compared to the wild type. We anticipate that thedeletion of acetyl-CoA synthase created a negative feedback effecton carbon dynamics, resulting in increased amounts of cysteine andisoflavone-associated metabolites. Metabolic profiling provided newinsight into the cascading effect of gene deletions that helps breedersto produce value-added nutritional seed traits.

Automated summary

A total of 718 metabolites were identified in the leaves and seeds of a soybean mutant, which contains 21 deleted genes and exhibits higher protein content in seeds. Among these metabolites, 164 were found only in seeds, 89 only in leaves, and 465 in both tissues. The mutant showed higher abundance of certain flavonoids and other metabolites in leaves compared to the wild type, as well as increased cysteine content in both leaves and seeds. This study provides valuable insights into the metabolic effects of gene deletions in soybean and their potential application in breeding improved nutritional traits.