Exogenous γ-aminobutyric acid strengthens phenylpropanoid and nitrogen metabolism to enhance the contents of flavonoids, amino acids, and the derivatives in edamame

Gaobo Yu; Fengqiong Chen; Yating Wang; Qiusen Chen; Hanlin Liu; Jin Tian; Mengxue Wang; Chunyuan Ren; Qiang Zhao; Fengjun Yang; Yunyan Sheng; Jinpeng Wei; Yuxian Zhang

doi:10.1016/j.fochx.2022.100511

Exogenous γ-aminobutyric acid strengthens phenylpropanoid and nitrogen metabolism to enhance the contents of flavonoids, amino acids, and the derivatives in edamame

Food Chem X. 2022 Nov 15:16:100511. doi: 10.1016/j.fochx.2022.100511. eCollection 2022 Dec 30.

Authors

Gaobo Yu¹, Fengqiong Chen^{1

2}, Yating Wang¹, Qiusen Chen¹, Hanlin Liu¹, Jin Tian¹, Mengxue Wang¹, Chunyuan Ren¹, Qiang Zhao¹, Fengjun Yang¹, Yunyan Sheng¹, Jinpeng Wei¹, Yuxian Zhang¹

Affiliations

¹ Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang Province 163319, China.
² South China Agricultural University, Guangzhou, Guangdong Province 510642, China.

Abstract

γ-aminobutyric acid (GABA) has been reported to improve stress resistance in plants. Nonetheless, little is known about the effects of GABA on the nutritional quality and regulatory mechanisms of edamame. Therefore, we analyzed the flavonoid and amino acid (AA) metabolism and the effects of GABA on the nutrient content of edamame seeds through physiological and metabolomic analyses. Exogenous GABA increased endogenous GABA metabolism and GABA transaminase activity and enhanced the oxoglutarate content, which entered into nitrogen metabolism and increased the activity and expression of nitrogen metabolism-related enzymes, to accumulate AAs and bioactive peptides. Meanwhile, exogenous GABA induced the metabolism of flavonoids, including total flavonoids, anthocyanins, 6''-o-malonyglycitin, glycitin, ononin, cyanin, and ginkgetin, by increasing the activity and expression of flavonoid biosynthetic enzymes. This is the first study to reveal that GABA effectively improves the nutritional quality of edamame through the accumulation of AAs, bioactive peptides, isoflavones, anthocyanins, sugars, and organic acids.

Keywords: 4CL, 4-coumarate coenzyme A ligase; ANS, anthocyanidin synthase; C4H, cinnamic acid 4-hydroxylase; CHI, chalcone isomerase; CHS, chalcone synthase; DFR, dihydroflavanol 4-reductase; Edamame; F3H, flavanone 3-hydroxylase; F3′H, flavanone 3′-hydroxylase; Flavonoid metabolism; GABA, γ-aminobutyric acid; GABA-T, γ-aminobutyric acid transferase; GAD, glutamate decarboxylase; GDH, glutamate dehydrogenase; GOGAT, glutamate synthase; GOT, glutamic-oxaloacetic transaminase; GPT, glutamic-pyruvic transaminase; GR, glutathione reductase; GS, glutamine synthetase; GSH, glutathione; IFS, isoflavone synthase; NR, nitrate reductase; Nitrogen metabolism; Nutritional quality; PAL, phenylalanine ammonia-lyase; TCA cycle, tricarboxylic acid cycle; UFGT, UDP-glycose flavonoid glycosyltransferase; Vc, vitamin C; γ-Aminobutyric acid; γ-ECS, γ-glutamylcysteine synthetase.