Content Of Sulfur-containing Amino Acids Research Articles

Knockdown of β-conglycinin α' and α subunits alters seed protein composition and improves salt tolerance in soybean.

Soybean is an important plant source of protein worldwide. Increasing demands for soybean can be met by improving the quality of its seed protein. In this study, GmCG-1, which encodes the β-conglycinin α' subunit, was identified via combined genome-wide association study and transcriptome analysis. We subsequently knocked down GmCG-1 and its paralogues GmCG-2 and GmCG-3 with CRISPR-Cas9 technology and generated two stable multigene knockdown mutants. As a result, the β-conglycinin content decreased, whereas the 11S/7S ratio, total protein content and sulfur-containing amino acid content significantly increased. Surprisingly, the globulin mutant exhibited salt tolerance in both the germination and seedling stages. Little is known about the relationship between seed protein composition and the salt stress response in soybean. Metabonomics and RNA-seq analysis indicated that compared with the WT, the mutant was formed through a pathway that was more similar to that of active salicylic acid biosynthesis; however, the synthesis of cytokinin exhibited greater defects, which could lead to increased expression of plant dehydrin-related salt tolerance proteins and cell membrane ion transporters. Population evolution analysis suggested that GmCG-1, GmCG-2, and GmCG-3 were selected during soybean domestication. The soybean accessions harboring GmCG-1Hap1 presented relatively high 11S/7S ratios and relatively high salt tolerance. In conclusion, knockdown of the β-conglycinin α and α' subunits can improve the nutritional quality of soybean seeds and increase the salt tolerance of soybean plants, providing a strategy for designing soybean varieties with high nutritional value and high salt tolerance.

Identification and Expression Analysis of Sulfate Transporter Genes Family and Function Analysis of GmSULTR3;1a from Soybean.

Sulfate transporters (SULTRs) are essential for the transport and absorption of sulfate in plants and serve as critical transport proteins within the sulfur metabolism pathway, significantly influencing plant growth, development, and stress adaptation. A bioinformatics analysis of SULTR genes in soybean was performed, resulting in the identification and classification of twenty-eight putative GmSULTRs into four distinct groups. In this study, the characteristics of the 28 GmSULTR genes, including those involved in collinearity, gene structure, protein motifs, cis-elements, tissue expression patterns, and the response to abiotic stress and plant hormone treatments, were systematically analyzed. This study focused on conducting a preliminary functional analysis of the GmSULTR3;1a gene, wherein a high expression level of GmSULTR3;1a in the roots, stems, and leaves was induced by a sulfur deficiency and GmSULTR3;1a improved the salt tolerance. A further functional characterization revealed that GmSULTR3;1a-overexpressing soybean hairy roots had higher SO42-, GSH, and methionine (Met) contents compared with the wild-type (WT) plant. These results demonstrate that the overexpression of GmSULTR3;1a may promote the sulfur assimilation metabolism and increase the content of sulfur-containing amino acids in plants.

Sulfate transport and metabolism: strategies to improve the seed protein quality.

Sulfur-containing amino acids (SAA), namely methionine, and cysteine are crucial essential amino acids (EAA) considering the dietary requirements of humans and animals. However, a few crop plants, especially legumes, are characterized with suboptimal levels of these EAA thereby limiting their nutritive value. Hence, improved comprehension of the mechanistic perspective of sulfur transport and assimilation into storage reserve, seed storage protein (SSP), is imperative. Efforts to augment the level of SAA in seed storage protein form an integral component of strategies to balance nutritive quality and quantity. In this review, we highlight the emerging trends in the sulfur biofortification approaches namely transgenics, genetic and molecular breeding, and proteomic rebalancing with sulfur nutrition. The transgenic 'push and pull strategy' could enhance sulfur capture and storage by expressing genes that function as efficient transporters, sulfate assimilatory enzymes, sulfur-rich foreign protein sinks, or by suppressing catabolic enzymes. Modern molecular breeding approaches that adopt high throughput screening strategies and machine learning algorithms are invaluable in identifying candidate genes and alleles associated with SAA content and developing improved crop varieties. Sulfur is an essential plant nutrient and its optimal uptake is crucial for seed sulfur metabolism, thereby affecting seed quality and yields through proteomic rebalance between sulfur-rich and sulfur-poor seed storage proteins.

Some biochemical characteristics of the hairy roots of Pisum sativum L. mutants

Two high-protein root cultures of vegetable pea mutants were received [1]. In continuation a PCR analysis of the obtained root cultures genes was carried out according [2] and the amino acid composition of the cultures protein was clarified in a dry product on the AAA 339TM device [3]. Obtained results confirmed the absence of rhizobia contamination of the cultures, which grow steadily on a hormone-free media for 5 years. PCR analysis revealed that fourrolgenesA,B,C,Dwere inserted into the genome of the root culture with genotypeafaftltl, and two —rol Candrol D— in the genome of the root culture with genotypetltl. The protein composition of the obtained cultures was represented by essential and non-essential amino acids and some others. In four inserts culture, the content of essential, ketogenic, proteinogenic and sulfur-containing amino acids prevailed by 1.5–2 times. Two inserts culture has twice as much aspartic acid and proline. Both cultures lacked tryptophan. The number of inserts determines the amino acid composition most likely.

Changes in the amino acid pool in the rat parietal lobe and hippocampus with incomplete cerebral ischemia

Introduction. Amino acids and their derivatives are involved in synaptic transmission as neurotransmitters and neuromodulators, and some of them are involved in the formation of neurotransmitters of the nervous system. Therefore, the study of the state of the amino acid pool in incomplete cerebral ischemia plays a significant role.The objective was to assess the nature of changes in amino acid pool and evaluate their participation in oxidative processes in rats with incomplete cerebral ischemia.Methods and materials. The experiments were carried out on 16 male outbred white rats weighing 260±20 g in compliance with the requirements of the Directive of the European Parliament and of the Council No. 2010/63/EU of September 22, 2010 on the protection of animals used for scientific purposes.Results. Compared with the indicators in the control group, rats with an ischemic period of 1 hour in the parietal lobe had a decrease in the content of sulfur-containing amino acids: methionine by 12 % and cysteate by 28 %. In addition, there was an increase of L-arginine in the parietal lobe by 39 %, and in the hippocampus – by 56 %.Conclusions. The following changes are characteristic for one-hour incomplete cerebral ischemia: a decrease in the content of sulfur-containing amino acids, with a decrease in both methionine and an increase in the content of L-arginine. Changes in the parietal lobe and hippocampus had a similar nature, except for the absence of a drop in the level of cysteate in the hippocampus, as a reflection of the higher sensitivity of the parietal lobe to oxygen deficiency, compared with the hippocampus.

СЕРОСОДЕРЖАЩИЕ АМИНОКИСЛОТЫ И РИСК РАЗВИТИЯ АРТЕРИАЛЬНОЙ ГИПЕРТЕНЗИИ У ДЕТЕЙ

Introduction. Currently, sulfur-containing amino acids are potential candidates as risk factors for cardiovascular disease. The purpose: to establish the role of sulfur-containing amino acids and their derivatives in the risk of developing arterial hypertension in children. Matherial and methods. 111 children aged 14 to 18 years were examined. All patients were divided into 3 groups: the 1st group (n=51) consisted of children with arterial hypertension, the 2nd group (n=30) – with high normal blood pressure, the 3rd group – 30 healthy children. The content of sulfur-containing amino acids and their derivatives in blood plasma was determined by high-performance liquid chromatography. Result. The concentration of sulfur-containing amino acids methionine, homocysteine, cysteine and cysteinylglycine in the blood plasma of children with arterial hypertension tend to increase in comparison with the group of healthy children. Pathological decrease in endothelium-dependent vasodilation accompanied by an increase in the concentration of methionine, homocysteine, cysteine, cysteinylglycine, glutathione in blood plasma and a decrease – taurine. A prognostic model has been developed based on the determination of the concentration of homocysteine and cysteinylglycine in the blood plasma of children. With a calculated value of p≥0,44, makes it possible to predict a high probability of arterial hypertension with a sensitivity of 90,2%, a specificity of 66,7% and a diagnostic efficiency of 82,1%. Conclusions. The concentration of sulfur-containing amino acids methionine, homocysteine, cysteine and cysteinylglycine in the blood plasma of children with arterial hypertension tend to increase in comparison with the group of healthy children.

Identification and Mapping of QTLs for Sulfur-Containing Amino Acids in Soybean (Glycine max L.)

Soybean is a major source of high-quality protein for humans and animals. The content of sulfur-containing amino acids (SAA) in soybean is insufficient, which has become the main factor limiting soybean nutrition. In this study, we used the high-density genetic maps derived from Guizao 1 and Brazil 13 to evaluate the quantitative trait loci of cysteine (Cys), methionine (Met), SAA, glycinin (7S), β-conglycinin (11S), ratio of glycinin to β-conglycinin (RGC), and protein content (PC). In genetic map linkage analysis, the major and stable 44 QTLs were detected, which shared nine bin intervals. Among them, the bin interval (bin157-bin160) on chromosome 5 was detected in multiple environments as a stable QTL, which was linked to 11S, 7S, RGC, and SSA. Based on the analysis of bioinformatics and RNA-sequencing data, 16 differentially expressed genes (DEGs) within these QTLs were selected as candidate genes. These results will help to elucidate the genetic mechanism of soybean SAA-related traits and provide the basis for the gene mining of sulfur-containing amino acids.

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

Soybean proteins are limited by their low contents of methionine and cysteine. Herein, 7S globulin accumulation was reduced using RNA interference to silence CG-β-1 expression, and the content of the A2B1a subunit was largely increased under the soybean seed-specific oleosin8 promoter. The results showed that the sulfur-containing amino acid content in soybean seeds drastically improved, reaching 79.194 nmol/mg, and the 11S/7S ratio had a 1.89-fold increase compared to the wild-type acceptor. The secondary structures of 11S globulin were also altered, and the β-sheet content increased with decreasing β-turn content, which was confirmed by Fourier transform infrared spectroscopy, Raman spectroscopy and circular dichroism analysis. Our findings suggested that raising the accumulation of 11S glycinin at the expense of reducing the content of 7S globulin is an attractive and precise engineering strategy to increase the amount of sulfur-containing amino acids, and soybean proteins with A2B1a subunits of 11S isolates improved, and β-subunits of 7S fractions reduced simultaneously might be an effective new material for food production.

Difference in the nutritional, in vitro, and functional characteristics of protein and fat isolates of two Indian chia (Salvia hispanica L) seed genotypes with variation in seed coat color.

This study aimed to determine the association between the seed coat color of two chia seed genotypes for their composition, protein content, amino acid, and fatty acid profiles. The optimal pH for protein isolation for both genotypes (BCPI and WCPI) was 10, based on protein purity and solubility. Fatty acid profiling indicated, overall, 18 different fatty acids higher in BCPI10 with linolenic acid domination (∼66%) followed by linoleic acid (∼19%) and oleic acid (∼6%), contributing PUFAs (∼86%). Optimized protein isolates, black (BCPI10) and white (WCPI10) chia, had shown purity, L*-value, solubility, and yields of 90.65%, 75.86%, 77.75%, 11.30%, and 90.00%, 77.83%, 76.07%, 10.69%, respectively. BCPI10 depicted higher EAA (33.19g/100 g N) and EEA indices (57.676%) compared to WCPI10 (32.14g/100 g N) and 56.360%, respectively.Amino acid profiling indicated higher, PER, TAA, TEAA, TNEAA, TAAA, TBA, acidic AA values for BCPI10, and higher leucine/isoleucine ratio for WCPI10 having leucine and sulfur amino acids as limiting amino acids. BCPI10 had higher sulfur-containing amino acid contents, as the main contributor to the albumin a water-soluble fraction, leading to its higher in vitro digestibility (71.97%) than WCPI10 (67.70%). Both isolates exhibited good WHC and OHC of 3.18, 2.39 and 3.00, 2.20, respectively. Both protein isolates had similar ∆Td (°C) values with some variation in FTIR spectrum from 1000 cm-1 to 1651cm-1 having more peak intensity for BCPI10. SDS-PAGE indicated bands at 150kDa, representing globulin and mild bands at 25-33kDa for glutelin and albumin. A significant (p<0.05) variation reported in this study for protein and lipid profiles of both genotype attributes to genetic differences between the seeds. PRACTICAL APPLICATION: Based on the nutritional profile, both chia seed isolates (black and white) are suitable for consumption with an edge for black seed when supplemented with their limiting amino acids. The high values of the functional properties and structural characteristics combined with high nutritional values make the chia protein isolate an excellent source of raw material for various food formulations. Fatty acid profile of the oils from the genotypes showed the presence of high amounts of unsaturated fatty acids, especially the PUFAs with more number of fatty acids in black chia seed. The excellent lipid profile of chia seed oil indicates the benefit of using chia seed oil as a source of essential fatty acids in the human diet for optimal health.

СОДЕРЖАНИЕ СЕРОСОДЕРЖАЩИХ АМИНОКИСЛОТ И РОДСТВЕННЫХ СОЕДИНЕНИЙ В ПЛАЗМЕ КРОВИ КРЫС ПРИ РАЗНЫХ ТИПАХ АЛКОГОЛЬНОЙ ИНТОКСИКАЦИИ

Background. Change of the content of sulfur-containing amino acids and their metabolites is one of the pathochemical mechanisms of alcohol intoxication. Purpose of the study. To study the effect of chronic and intermittent alcohol intoxication on the content of sulfurcontaining amino acids and related compounds in the rat blood plasma. Material and methods. Thirty white outbred rats weighing 180-220 g. The content of free amino acids and biogenic amines was determined by HPLC. Results. A 14-day chronic alcohol intoxication was accompanied by a significant decrease in the level of methionine and an increase in the level of homocysteine in the blood plasma. The concentration of glutathione increased by 5%. In the intermittent alcohol intoxication IAI-4 group, the homocysteine content also increased, as did the level of homoserine and cystathionine in the IAI-1 group. Conclusions. Сhronic and intermittent alcohol intoxications cause similar violations of the level of sulfur-containing amino acids and their metabolites in the rat blood plasma.

Genome-wide association identifies several QTLs controlling cysteine and methionine content in soybean seed including some promising candidate genes

Soybean is an important source of protein, oil and carbohydrates, as well as other beneficial nutrients. A major function of proteins in nutrition is to supply adequate amounts of amino acids. Although they are essential for human nutrition, the sulfur-containing amino acids cysteine (Cys) and methionine (Met) are often limited and the genetic control of their content in soybean seeds is poorly characterized. This study aimed to characterize the phenotypic variation and identify quantitative trait loci (QTL) associated with Cys and Met content in a core set of 137 soybean lines, representative of the genetic diversity among Canadian short-season soybean, spanning maturity groups 000-II (MG000-II). Significant phenotypic differences were found among these lines for Cys, Met and Cys + Met content. Using both a mixed linear model and six multi-locus methods with a catalogue of 2.18 M SNPs, we report a total of nine QTLs and seventeen QTNs of which seven comprise promising candidate genes. This work allowed us to reproducibly detect multiple novel loci associated with sulfur-containing amino acid content. The markers and genes identified in this study may be useful for soybean genetic improvement aiming to increase Cys and Met content.

Distribution of calcium, phosphorus, sulfur, magnesium, potassium, and sodium in major fractions of donkey milk

The aim of this study was to evaluate the concentrations of Ca, P, S, Mg, K, and Na, and their distribution in major fractions of donkey milk (i.e., fat, casein, whey proteins, and aqueous phase). Individual milk samples were collected by mechanical milking from 16 clinically healthy lactating donkeys. Milk yield per milking was recorded and milk gross composition, casein content, and pH were determined. Whole milk samples were centrifuged to separate fat and to obtain skim milk. Skim milk samples were ultracentrifuged to separate a sedimentable casein pellet and to obtain a supernatant whey (soluble) fraction, which was then ultrafiltered to obtain the aqueous phase of donkey milk. Whole milk and the processed samples were analyzed for the aforementioned elements by inductively coupled plasma-mass spectrometry. The concentration of elements associated with fat, casein, and whey proteins was then calculated. All the Na was present in the aqueous phase. The fat fraction in donkey milk carried very little or none of the investigated elements. The majority of Ca (62.9%) and P (53.1%) was associated with casein, and the rest of these elements was mostly present in the aqueous phase. The majority of Mg was present in the aqueous phase, but a relevant part (32.6%) was associated with the casein fraction. No K was associated with casein. On a molar basis, the ratio of colloidal Ca and P to casein (mmol/g of casein) was more than double the values reported in literature for cow milk. The correlation coefficient was negative between milk pH and P in the ultracentrifuged (r = -0.81) and ultrafiltered (aqueous) fraction (r = -0.66). Milk pH correlated positively with colloidal Ca (r = 0.59) and with the ratio of colloidal Ca to casein (mmol/g of casein; r = 0.68). Colloidal Ca and P were positively correlated (r = 0.64). These data suggest that the high ratio of colloidal Ca and P to donkey casein micelles is due to a larger amount of colloidal calcium phosphate bound to casein micelles compared with literature data on cow milk. The percentage of elements associated with whey proteins was less than 5% for Ca, P, and K, but Mg reached approximately 9% of total Mg. The majority of S (63.6%) was associated with whey proteins, and only one-fourth of this element was associated with casein, indicating a higher content of sulfur-containing amino acids in donkey whey proteins than in casein.

Different commercial soy protein isolates and the characteristics of Chiba tofu

Twenty different cold gels were made by adding transglutaminase enzyme and using soy protein isolate (SPI) powders from different manufacturers to investigate their potential as an ingredient in Chiba tofu. The study showed that SPI gives Chiba tofu high hardness and springiness, and excellent quality when its sulfur-containing amino acid content is >2.83%, β-sheets content is >52.1% and the 11S:7S ratio is > 1.88. Moreover, low field nuclear magnetic resonance confirmed that the water mobility of the best sample left more water in the gel network. Intermolecular force results indicated that the hydrophobic interactions, disulfide bonds and non-disulfide covalent bonds were the main chemical forces maintaining the structure of the gel network. The scanning electron microscopy showed that the best Chiba tofu sample had a more continuous and uniform gel network structure. Overall, the characteristics of SPI have an important influence on the quality of Chiba tofu.

Porin from Marine Bacterium Marinomonas primoryensis KMM 3633T: Isolation, Physico-Chemical Properties, and Functional Activity.

Marinomonas primoryensis KMM 3633T, extreme living marine bacterium was isolated from a sample of coastal sea ice in the Amursky Bay near Vladivostok, Russia. The goal of our investigation is to study outer membrane channels determining cell permeability. Porin from M. primoryensis KMM 3633T (MpOmp) has been isolated and characterized. Amino acid analysis and whole genome sequencing were the sources of amino acid data of porin, identified as Porin_4 according to the conservative domain searching. The amino acid composition of MpOmp distinguished by high content of acidic amino acids and low content of sulfur-containing amino acids, but there are no tryptophan residues in its molecule. The native MpOmp existed as a trimer. The reconstitution of MpOmp into black lipid membranes demonstrated its ability to form ion channels whose conductivity depends on the electrolyte concentration. The spatial structure of MpOmp had features typical for the classical gram-negative porins. However, the oligomeric structure of isolated MpOmp was distinguished by very low stability: heat-modified monomer was already observed at 30 °C. The data obtained suggest the stabilizing role of lipids in the natural membrane of marine bacteria in the formation of the oligomeric structure of porin.

Preparation of Selenium-Enriched Yeast by Re-Using Discarded Saccharomyces cerevisiae from the Beer Industry for Se-Supplemented Fodder Applications

Both inorganic and organic selenium (Se) can prevent and treat various diseases caused by Se deficiency. However, organic Se has less toxicity and a higher absorption rate than inorganic Se. In this study, inorganic Se (Na2SeO3) was bio-transformed into Se-enriched discarded beer yeast (Se-enriched DB-yeast) through fermentation accumulation by re-using discarded Saccharomyces cerevisiae from the beer industry for Se-enriched fodder application. Through a single-factor experiment and L9(34)-orthogonal test for optimization of fermentation conditions, the Se content and biomass of Se-enriched DB-yeast were calculated as 14.95 mg/L and 7.3 g/L, respectively, under the optimized condition. The total amino-acid content of Se-enriched DB-yeast was increased by 9.9% compared with that from DB yeast. Additionally, alkaline amino-acid content was increased, whereas acidic amino-acid and sulfur-containing amino-acid contents were decreased. Reducing capacity, hydroxyl radical removal capacity, and sulfhydryl content after treatment with H2O2 of the Se-enriched DB-yeast extracted protein were obviously increased compared with those of the DB-yeast extracted protein. Mouse and genetically improved farmed tilapia (Oreochromis niloticus) (GIFT) bioassays showed that the Se sedimentation of organs and serum indexes after feeding Se-enriched DB-yeast-containing fodder were higher than those of DB-yeast-containing fodder. The half lethal dose (LD50) of Se-enriched DB-yeast (9260.0 mg/kg body weight (BW), 18.97 mg/kg of Se content, non-toxic level) was considerably higher than that of Na2SeO3 (20.0 mg/kg BW, 5.08 mg/kg of Se content, highly toxic level) against mouse. Therefore, Se-enriched yeast prepared by re-using discarded S. cerevisiae from beer industry fermentation accumulation has the potential to be a safe and effective Se-enriched fodder additive.

Wet-milled chickpea coproduct as an alternative to obtain protein isolates

This study evaluated the use of the wet-milled protein-rich chickpea coproduct to produce chickpea protein isolates following a short downstream process. The chemical and molecular composition, functionality and protein quality of the wet-milled protein isolates (WMPI) were determined and compared to a protein isolate produced by the isoelectric precipitation method (IPPI). WMPI had higher protein purity, lower fat content and higher fat absorption capacity compared to IPPI. The isolate and protein solubilities and emulsifying and foaming capacities were not affected by the wet-milling process but water holding capacity and foaming stability were diminished. The WMPI had comparatively slightly reduced in vitro protein digestibility and protein digestibility corrected amino acid score due to lower sulfur-containing amino acid content. SDS-PAGE indicated loss of protein fractions due to wet-milling but secondary structures were not affected according to ATR-FTIR spectra. The chickpea wet-milling protein coproduct was an adequate feedstock to obtain functional and value-added protein isolates.

Protein Quality, Secondary Structure and Effect of Physicochemical Factors on Emulsifying Properties of Irvingia gabonensis Almonds

Background: There is a constant search of new plant proteins, with adequate nutritional and functional properties, as well as bioactive properties and low-cost for utilization in various food formulations. Objective: The aim of this work was to access the nutritional and functional potential of protein from Irvingia gabonensis, for utilization as ingredient or supplement in food. Methods: Proximate composition and amino acid were analyzed. Nutritional parameters were calculated from amino acid composition. Physicochemical properties and secondary structure of protein were determined. Finally, effect of oil to water ratio (OWR), pH and concentration on emulsifying properties was analyzed. Results: The flour contained 22.26% protein, 5.30% ash and 60% carbohydrates. Proteins contained all essential amino acids, with high content of Leu, Ile, Val, Thr and sulfur-containing amino acids. Essential amino acid index (69%), protein efficiency ratio (2.39-2.63) and biological value (79.91%) were studied. The maximum protein solubility (61%) was noticed at pH 8, while high hydrophobicity was observed at pH 2. A transition from an irregular secondary structure to a more ordered structure was found from pH 2-4 to pH 6-10. pH, OWR and concentration significantly affected emulsifying properties of Irvingia gabonensis almonds. The maximum emulsifying capacity (EC) was observed under acidic pH and high flour concentration. EC increased with increasing OWR and concentration, while decreased with increasing pH. High ES (25-35%) was observed at pH 4-8 and OWR of 1/3 to 1/2 (v/v), at flour concentration of 3-4% (w/v). Conclusion: Irvingia gabonensis showed good potential as food ingredient or supplement.

Physicochemical characterization of a navy bean (Phaseolus vulgaris) protein fraction produced using a solvent-free method

A solvent-free electrostatic separation method was employed to separate navy bean flour (NBF) into protein-rich (PR) and starch-rich (SR) fractions. The physicochemical properties of NBF and separated fractions were compared to proteins (navy bean isolate (NBI) and 7S globulin) prepared using a wet process. Gel electrophoresis confirmed that the protein distribution in the isolated fractions was similar to that of NBF. The protein profile of NBI and 7S globulin was found to be devoid of certain proteins that were found in the NBF and PR fraction. Amino acid analysis revealed that the NBI and 7S globulin had a lower content of sulfur-containing amino acids compared to NBF and the electrostatically isolated fractions. CD and fluorescence spectroscopy confirmed that denaturation of the proteins during the acid precipitation is likely. This novel solvent-free electrostatic separation process preserves the native protein structure found in NBF and improves the recovery of some of the smaller MW proteins.

Gene mining of sulfur-containing amino acid metabolic enzymes in soybean

The genes of sulfur-containing amino acid synthetases in soybean are essential for the synthesis of sulfur-containing amino acids. Gene mining of these enzymes is the basis for the molecular assistant breeding of high sulfur-containing amino acids in soybean. In this study, using software BioMercator2.1, 113 genes of sulfur-containing amino acid enzymes and 33 QTLs controlling the sulfur-containing amino acids content were mapped onto Consensus Map 4.0, which was integrated by genetic and physical maps of soybean. Sixteen candidate genes associated to the synthesis of sulfur-containing amino acids were screened based on the synteny between gene loci and QTLs, and the effect values of QTLs. Through a bioinformatic analysis of the copy number, SNP information, and expression profile of candidate genes, 12 related enzyme genes were identified and mapped on 8 linkage groups, such as D1a, M, A2, K, and G. The genes corresponding to QTL regions can explain 6%?38.5% genetic variation of sulfur-containing amino acids, and among them, the indirect effect values of 9 genes were more than 10%. These 12 genes were involved in sulfur-containing amino acid metabolism and were highly expressed in the cotyledons and flowers, showing an abundance of SNPs. These genes can be used as candidate genes for the development of functional markers, and it will lay a foundation for molecular design breeding in soybean.

Quantitative trait locus analysis of seed sulfur-containing amino acids in two recombinant inbred line populations of soybean

Soybean (Glycine max (L.) Merr.) is a major source of plant protein for humans and livestock. Deficiency of sulfur-containing amino acids (cysteine and methionine) in soybean protein is a main limitation of soybean meal as an animal feed ingredient. The objectives of this study were to identify and validate quantitative trait loci (QTLs) associated with cysteine and methionine contents in two recombinant inbred line (RIL) populations, and to analyze the genetic effects of individual QTLs and QTL combinations in soybean. Both the mapping population of SD02-4-59 × A02-381100 and validation population of SD02-911 × SD00-1501 were evaluated for cysteine and methionine contents in multiple environments. Correlation analysis indicated that there was a highly positive correlation between cysteine and methionine contents. Significant positive correlations were also observed between the sulfur-containing amino acid contents and protein content. In the mapping population, eight QTLs for both cysteine and methionine contents were consistently detected in any individual environment and the average data over all three environments. Three of these QTLs were confirmed in the validation population. A comparison with the previous studies indicated that most of the genomic regions linked to the QTLs for the sulfur-containing amino acids were also associated with protein content. Cumulative effects of multiple QTLs for the traits were significant in both populations. This information should be useful for the improvement of the levels of protein and amino acids in soybean seeds.