Metabolic profiling of a fast neutron soybean mutant reveals increased abundance of isoflavones

Authors: Islam, Nazrul - Naz; Krishnan, Hari; Slovin, Janet; Natarajan, Savithiry - Savi

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/22/2023
Publication Date: 6/21/2023
Citation: Islam, N., Krishnan, H.B., Slovin, J.P., Natarajan, S.S. 2023. Metabolic profiling of a fast neutron soybean mutant reveals increased abundance of isoflavones. Journal of Agricultural and Food Chemistry. 71(26):9994-10003. https://doi.org/10.1021/acs.jafc.3c01493.
DOI: https://doi.org/10.1021/acs.jafc.3c01493

Interpretive Summary: Soybean is considered a valuable source of raw materials in food processing and pharmaceutical industries for bioactive phenolic compounds that are beneficial for human health. In the present study, we have investigated the dynamics of metabolities produced in leaves and seeds of a fast neutron radiated mutant. A high throughput and sensitive mass spectrometry technique (tandem mass tag) was utilized to identify tissue metabolites in altered soybeans with 20 known gene deletions. We found differentally accumulated metabolites and amino acids between mutant and wild type soybeans. Several isoflavones, sulfur containing metabolites and cysteine were increased in the mutant compared to the wild type soybeans. Our results contribute to a better understanding of metabolic genes and the synthesis and accumulation of metabolities and amino acids that will aid breeders, geneticists and plant physiologists in developing soybean with enhanced nutritional profiles for value-added food products.

Technical Abstract: A total of 718 metabolites were identified in leaves and seeds of the soybean (Glycine max (L.) Merr., Fabaceae) fast neutron (FN) mutant 2012CM7F040p05ar154bMN15, which was previously shown to have 21 genes deleted and higher protein content in seeds as compared to wild-type. Among the identified metabolites, 164 were found only in seeds, 89 only in leaves, and 465 in both leaves and seeds. Metabolites that exhibited higher abundance in the mutant leaf than in the wild type include the flavonoids afromosin, biochanin A, dihydrodaidzein, and apigenin. Mutant leaves also exhibited a higher accumulation of glycitein-glucoside, dihydrokaempferol, and pipecolate. The seed-only metabolites that were found in higher abundance in the mutant compared to the wild type included 3-hydroxybenzoate, 3-aminoisobutyrate, coenzyme A, N-acetyl-ß-alanine, and 1-methylhistidine. Among several amino acids, the cysteine content increased in the mutant leaf and seed when compared to the wild type. We anticipate that the deletion of acetyl-CoA synthase created a negative feedback effect on carbon dynamics, resulting in increased amounts of cysteine and isoflavone-associated metabolites. Metabolic profiling provided new insight into the cascading effect of gene deletions that helps breeders to produce value-added nutritional seed traits.