Sulfur fertility management to enhance methionine and cysteine in soybeans

Abstract

BACKGROUND: Soybeans (Glycine max) are a major protein source both for humans and non-ruminant livestock; however, the usability of soybean protein is limited by the concentration of the essential sulfur (S)-containing amino acids methionine and cysteine (MET+CYS). Traditional efforts to improve protein quality in soybeans have largely been focused on plant breeding but soil S fertility may also influence seed MET+CYS concentration. Crop S deficiencies are increasingly common due to soil depletion by high yields and reduced atmospheric deposition. We report on a survey of commercial soybean fields and two replicated split-plot field experiments in the mid-Atlantic region, USA. The experimental treatments were two levels (0 or 100 kg S ha −1 ) of broadcast gypsum (CaSO 4 ) and two levels (0 or 11 kg-S ha −1 ) of foliar Epsom salt (MgSO 4 ) applied to two soybean cultivars. The objective was to assess the variability of, and effect of, S fertilization on S and MET+CYS concentrations in soybean seeds.RESULTS: Sulfur ranged from 2.35 to 3.54 mg g −1 and MET+CYS ranged from 5.5 to 9.2 mg g −1 protein in seeds from commercial fields surveyed. Sulfur application increased seed MET+CYS concentration 1.3 to twofold in two replicated field experiments. Overall, MET+CYS concentration in protein ranged from 3.9 to 12.8 mg g −1 and was linearly predicted (R 2 = 0.65) by seed S. CONCLUSIONS: Soybean seed S and MET+CYS concentrations vary widely. We show that field-scale S application can greatly enhance soybean MET+CYS content and therefore protein quality.

Unfolding the Dynamics of Mineral Nutrients and Major Storage Protein Fractions during Soybean Seed Development

“…Albumin and globulin proteins account for ca. 70% of the soybean seed’s proteome. , Although similar biosynthesis trends have been previously observed, , most of these studies have focused on assessing the seed’s total protein content or the storage proteins on mature seeds as a function of different agricultural traits. − , Therefore, a precise profile of storage proteins biosynthesis throughout the seed development was poorly explored. The results presented herein confirm that the storage protein accumulation escalates during the cell elongation phases, i.e., in the aftermath of the cease in cell division and differentiation taking place up to the R 5.5 developmental stages (Figure ).…”

“…Given that S, alongside playing essential roles in plant metabolism, − also encompasses both cysteine and methionine sulfur-amino acid residues in the primary structure of glycinin, these results present resounding evidence that the strong correlations observed between the storage proteins and sulfur concentration throughout soybean seed development (Figure a,b) are indeed related to sulfur’s important role as the building blocks of the glycinin amino acid residue backbone. This is supported by agricultural trials where soil and foliar sulfur fertilization have been reported to change the profile of storage proteins and increase the total protein content in soybean seeds …”

“…Although the content of storage proteins might be affected by a myriad of factors, − several pieces of evidence suggest that mineral nutrients play a crucial role in plant protein biosynthesis. − Higher protein content and β-conglycinin suppression were observed in developing soybean seed supplied with nitrogen (N) and sulfur (S) sources, respectively, whereas an opposite trend was found for β-conglycinin’s β-peptide of Petunia hybrida seeds under S deficiency . Furthermore, sulfur-based fertilizers also promoted increased glycinin or total globulin fraction , as well as methionine and cysteine amino acids in soybean seeds …”

Increased sulfur-containing amino acid content and altered conformational characteristics of soybean proteins by rebalancing 11S and 7S compositions

“…To date, new cultivars with high SAA contents have not been reported, although several QTLs and candidate alleles associated with amino acid contents have been found (Panthee et al, 2006;Ramamurthy et al, 2014). S (MgSO 4 ) application increased the proportion of Met + Cys in soybean seeds (Rushovich and WeilSulfur, 2021), and this required the correct application of S, which might be complex. Moreover, materials with high sulfurcontaining amino acids have been influenced by environmental factors, nitrogen sources, and the availability of reduced forms of sulfur, which limits their use in field production.…”

Soy Consumption and the Risk of Type 2 Diabetes and Cardiovascular Diseases: A Systematic Review and Meta-Analysis

“…Animal protein is rich in a variety of essential amino acids, but also rich in fat and cholesterol, leading to a high incidence of various chronic diseases [ 2 ]. Additionally, soy protein does not contain cholesterol, and the contents of methionine and branched-chain amino acids (BCAAs) are low compared with animal proteins [ 3 , 4 ]. Although leucine or its metabolite β-hydroxy-β-methylbutyric acid can improve muscle function [ 5 ], aberrant metabolism of BCAAs and high circulating concentrations of BCAAs are a hallmark of metabolic disorders, including obesity, insulin resistance and type 2 diabetes mellitus, cancer, and heart failure [ 6 , 7 ].…”