Compositional variability in conventional and glyphosate-tolerant soybean (Glycine max L.) varieties grown in different regions in Brazil

The compositions of a diverse range of commercially available conventional and genetically modified (GM; glyphosate-tolerant) soybean varieties from maturity groups 8 and 5, respectively, grown in the northern and southern soybean regions of Brazil during the 2007-2008 and 2008-2009 growing seasons were compared. Compositional analyses included measurement of essential macro- and micronutrients, antinutrients, and selected secondary metabolites in harvested seed as well as measurement of proximates in both forage and harvested seed. Statistical comparisons utilized a mixed analysis of variance model to evaluate the relative contributions of growing season, soybean growing region, production site, phenotype (GM or conventional), and variety. The study highlighted extensive variability in the overall data set particularly for components such as fatty acids, vitamin E, and isoflavones. There were few differences between the GM and non-GM populations, and most of the variability in the data set could be attributed to regional and variety differences. Overall, the results were consistent with the expanding literature on the lack of any meaningful impact of transgene insertion on crop composition.     

Supernatant solution phosphorus concentrations required by five soybean (Glycine max) cultivars

Abstract

Dry matter yields at flowering and seed yield responses of five soybean cultivars (Bragg, Semstar, Flegler, Davis and Wills) to six soil phosphorus levels in an Oxic Paleustalf were determined in a pot experiment. Ninety percent maximum dry matter yield at flowering was attained at the following supernatant solution P concentrations (determined from P sorption curves): Bragg, 0.012 μg ml^‐1; Davis, 0.009 μg ml^‐1; Semstar, 0.010 μg ml^‐1; Flegler, 0.011 μg ml^‐1; Wills, 0.012 μg ml^‐1. Ninety percent maximum seed yield was attained at a supernatant solution P concentration of 0.007 μg ml^‐1 by Bragg, Semstar, Flegler and Wills. Davis required 0.011 μg P ml^‐1 for 90% maximum seed yield.

It is concluded from these results that Bragg, Semstar, Flegler and Wills will have similar phosphorus fertilizer requirements, but Davis will require larger additions of phosphorus than the other cultivars for maximum seed yield.     

Volatile components in fermented soybean (Glycine max) curds.

Volatile components of three commercial fermented soybean (Glycine max) curds (FSC) (A-C) were extracted using a simultaneous steam distillation and extraction apparatus, and extracts were analyzed by gas chromatography/mass spectrometry. A total of 111 compounds was found. Sixty-three compounds were common to all three brands. Brands A, B, and C contained 90, 90, and 82 components, respectively. Major classes of compounds included alcohols (32) and esters (25). Similarities and differences existed in the composition of the FSC samples. Twelve common compounds including six esters, four alcohols, one ketone, and one miscellaneous compound had a dry weight of >1000 microg/kg of sample. Quantitative differences existed among the commercial brands (p<0.05). The quantity of ethanol detected might produce large numbers of ethyl esters that contribute to the desirable fruity and floral notes for the final products.     

Radiation-induced enhancement of antioxidant contents of soybean (Glycine max Merrill)

Soybean samples were treated with gamma-radiation doses between 0.5 and 5 kGy for achieving insect disinfestation and microbial decontamination. Nutritional quality of soybeans with respect to antioxidant isoflavone content was tested in radiation-treated and untreated samples. Changes in major isoflavones such as genistein, diadzein, glycetein, and their glycosides were monitored by high-performance liquid chromatography. Interestingly, a decrease in content of glycosidic conjugates and an increase in aglycons were noted with increasing radiation dose. Antioxidant potential measured as percent 1,1-diphenyl-2-picrylhydrazyl scavenging activity showed an increasing trend with dose, indicating that radiation processing as a method of food preservation has a positive nutritional implication.     

Antimutagenic activity of isoflavones from soybean seeds (Glycine max merrill)

Two isoflavones, daidzein (1) and genistein (2), were isolated from soybean hypocotyls. Daidzein and genistein showed a suppressive effect on umu gene expression of the SOS response in Salmonellatyphimurium TA1535/pSK1002 against the mutagen 3-amino-1, 4-dimethyl-5H-pyrido[4,3b]indole (Trp-P-1), which requires liver metabolizing enzymes. Compound 1 suppressed 73% of the SOS-inducing activity at concentrations <0.74 micromol/mL, and the ID(50) value was 0.37 micromol/mL. Compound 2 suppressed 95% of the SOS-inducing activity at concentrations <0.74 micromol/mL, and the ID(50) value was 0.17 micromol/mL. Compounds 1 and 2 were also assayed with the mutagen 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide) and activated Trp-P-1. In addition to the antimutagenic activities of daidzein and genistein against Trp-P-1, frylfuramide and activated Trp-P-1 were assayed by an Ames test using S. typhimurium TA100.     

Volatile flavor components in red fermented soybean (Glycine max) curds

Red fermented soybean (Glycine max) curds (FSC) were extracted with a simultaneous steam distillation and extraction (SDE) apparatus and analyzed by gas chromatography-mass spectrometry (GC-MS) and further evaluated by gas chromatography-mass spectrometry-flame ionization detector-olfactometry (GC-MS-FID-O). A combined total of 89 compounds were identified from three samples (A-C). The numbers of components identified (samples A-C) were 87, 85, and 81, respectively, which were divided into 10 compound classes. The quantity of 48 compounds was statistically significant (p < 0.05). Sample B generally had the lowest level, whereas sample C had the higher level of each common component among the samples. GC-MS-FID-O analyses showed that the majority of the fruity, diacetyl, cantaloupe-like odors were eluted early during the run (RI < 1100), followed by the meaty flavor, rosy, and prune-like aromas (RI > 1100). Ethyl 2-methylpropanoate, 2,3-butanedione, ethyl butanoate, ethyl 2-methylbutanoate, 3-(methylthio)propanal, benzeneacetaldehyde, and ethyl 3-phenylpropionate were found to be important common components contributing to the characteristic aroma of red FSCs.     

A semi-pilot-scale procedure for isolating and purifying soybean (Glycine max) lectin

Availability of gram quantities of purified soybean lectin (SBL) to scientists will foster discovery of novel biomedical applications of the lectin and provide the opportunity to investigate the antinutritional effects of SBL in soybean-consuming food animals and poultry. Therefore, a semi-pilot-scale procedure for isolating and purifying SBL was designed. Defatted soyflour was extracted overnight with 0.9% NaCl at 4 degrees C. The extract obtained was filtered (0.45 microm membrane) and subjected to affinity chromatography using a column containing N-acetyl-D-galactosamine resin that is specific for SBL. Bound SBL was eluted off the column with 0.14 M galactose solution. The eluent was ultrafiltered (30 kDa), and the resulting solution (SBL and water) was freeze-dried. Electrophoretic analysis and hemagglutination assay revealed that the freeze-dried SBL was similar to Sigma-grade SBL in purity and activity (35 and 33 HU/mg protein, respectively). The procedure yielded 141 mg of SBL/100 g of soyflour.     

Oxalate content of soybean seeds (Glycine max: Leguminosae), soyfoods, and other edible legumes

Consumption of soybeans and food products made from them is increasing because of their desirable nutritional value. However, the oxalate content of seeds from 11 cultivars of soybean showed relatively high levels of total oxalate from 0.67 to 3.5 g/100 g of dry weight. Oxalate primarily was found as calcium oxalate crystals. Thirteen tested commercial soyfoods contained between 16 and 638 mg of total oxalate per serving. These values compare to those of three other legume foods, peanut butter, refried beans, and lentils, which contained 197, 193, and 100 mg of total oxalate per serving, respectively. After oxalate has been absorbed from the diet, it cannot be metabolized and is excreted by the kidney into urine, where it binds to calcium forming an insoluble salt that may precipitate to form kidney stones. The amounts of total oxalate in soybean seeds, soy foods, and other common legume foods exceed current recommendations for oxalate consumption by individuals who have a history of calcium oxalate kidney/urinary stones. This study serves as the basis to find soybean cultivars lower in oxalate, which will have lower risk for kidney stone formation after human consumption.     

Characterization of storage proteins in wild (Glycine soja) and cultivated (Glycine max) soybean seeds using proteomic analysis

A combined proteomic approach was applied for the separation, identification, and comparison of two major storage proteins, beta-conglycinin and glycinin, in wild (Glycine soja) and cultivated (Glycine max) soybean seeds. Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) with three different immobilized pH gradient (IPG) strips was an effective method to separate a large number of abundant and less-abundant storage proteins. Most of the subunits of beta-conglycinin were well-separated in the pH range 3.0-10.0, while acidic and basic glycinin polypeptides were well-separated in pH ranges 4.0-7.0 and 6.0-11.0, respectively. Although the overall distribution pattern of the protein spots was similar in both genotypes using pH 3.0-10.0, variations in number and intensity of protein spots were better resolved using a combination of pH 4.0-7.0 and pH 6.0-11.0. The total number of storage protein spots detected in wild and cultivated genotypes was approximately 44 and 34, respectively. This is the first study reporting the comparison of protein profiles of wild and cultivated genotypes of soybean seeds using proteomic tools.     

Isoflavone levels in five soybean (Glycine max) genotypes are altered by phytochrome-mediated light treatments

The objective of the present study was to determine whether concentrations of different isoflavones (puerarin, genistein, genistin, daidzein, and daidzin) in shoots and roots of five selected soybean genotypes would respond the same or differently to red (650 nm peak transmittance) and far-red (750 nm peak transmittance) light treatments given under controlled environments. Levels of isoflavones (mg g(-1) dry weight biomass) present in seeds, control roots, and shoots and 10 day light-treated seedlings (light, dark, red, and far-red wavelengths) of soybean (Glycine max) were determined by high-performance liquid chromatography analysis in comparison with known isoflavone standards. Seeds of the five soybean genotypes studied consistently stored most of their isoflavones as glucosyl conjugates (e.g., daidzin, genistin, and puerarin). For the five soybean genotypes, isoflavone levels were lower in the seeds as compared with roots plus shoots of control, time zero (first true leaf stage) seedlings. Following 10 days of the respective light treatments, we found that (i) isoflavone levels were enhanced in dark-grown plants over light-grown plants for three of the five genotypes (a new finding) and the reverse occurred for a single genotype (a typical response of legumes) and (ii) generally, far-red end of day (EOD) light treatment enhanced total isoflavone levels in roots plus shoots over red EOD light treatment. Results from the present study show that phytochrome does appear to play a role in regulating isoflavone levels in developing soybean seedlings and that this influence by red/far-red-mediated phytochrome reactions is strongly dependent on the genotypes selected for study.     

Quantification of seed ionome variation in 90 diverse soybean (Glycine max) lines

Climate change and rising carbon dioxide (CO₂) levels are expected to reduce the mineral nutrient content of soybean seeds. The main objective of this study was to survey diverse soybean germplasm for variation in seed elemental concentrations and their relationships between elements, protein content, and individual seed weight. Seeds from 90 soybean genotypes were weighed and subjected to inductively coupled plasma-mass spectrometry (ICP-MS) ionomics analysis and Carbon/Nitrogen (C/N) analysis to determine protein. The results demonstrated substantial variation with the possibility of significantly improving most mineral nutrients, especially selenium (Se), copper (Cu), iron (Fe), and manganese (Mn). This diverse survey identifies genotypes that can complement existing soybean breeding programs for improving seed nutritional quality. Correlation analysis identified two clusters of co-variant elements: zinc (Zn), phosphorus (P), and sulfur (S) as well as Zn, Cu, Se, and rubidium (Rb) were positively correlated with each other. Tolerable upper limits of Rb intake are not defined for humans illustrating the need to monitor trace elements along with desirable nutrients.     

Comparison of isoflavone concentrations in soybean (Glycine max (L.) Merrill) sprouts grown under two different light conditions

We determined and compared the composition and content of isoflavones in the cotyledon, hypocotyl, and root of 17 soybean sprout varieties grown under dark and light conditions. The total average isoflavone concentrations in 17 soybean sprout varieties were 2167 microg g(-1) (green sprout) and 2538 microg g(-1) (yellow sprout) in cotyledons, 1169 microg g(-1) (green sprout) and 1132 microg g(-1) (yellow sprout) in hypocotyls, and 2399 microg g(-1) (green sprout) and 2852 microg g(-1) (yellow sprout) in roots. There were no significant differences in total isoflavone concentrations between the green and yellow sprouts. However, significant differences in total isoflavone amounts were observed among the three organs, with roots exhibiting the highest total isoflavone concentrations followed by cotyledons and hypocotyls. Total daidzin concentrations of green (775 microg g(-1)) and yellow (897 microg g(-1)) sprouts increased to more than 4 times that in seeds (187 microg g(-1)). Yellow sprouts contained the highest (1122 microg g(-1)) total genistin concentrations, and green (155 microg g(-1)) and yellow (155 microg g(-1)) sprouts had more total glycitin concentrations than seeds. In cotyledons of green and yellow sprouts, genistin, daidzen, and glycitin constituted more than 67%, more than 28%, and less than 4% of the total isoflavone contents, respectively. In hypocotyls, total daidzin represented more than 45% of the total isoflavones, and total glycitin was higher than in cotyledons and roots. Malonylglycoside concentrations were highest in cotyledons, whereas glycoside concentrations were highest in hypocotyls and roots. The high accumulation of isoflavones in roots is consistent with isoflavones serving as signal molecules in the induction of microbial genes involved in soybean (Glycine max) nodulation.     

Phenolic composition and antioxidant activity in seed coats of 60 Chinese black soybean (Glycine max L. Merr.) varieties

Phenolics in black soybean seed coat (BSSC) are considered to be responsible for the health benefits of black soybean. BSSCs of 60 Chinese varieties were examined for phenolic contents, anthocyanin profiles, and antioxidant activity. Total phenolic and condensed tannin contents ranged from 512.2 to 6057.9 mg gallic acid equivalents/100 g and from 137.2 to 1741.1 mg (+)-catechin equivalents/100 g, respectively. Six anthocyanins (delphinidin-3-glucoside, cyanidin-3-galactoside, cyanidin-3-glucoside, petunidin-3-glucoside, peonidin-3-glucoside, and malvidin-3-glucoside) were detected by HPLC. Total anthocyanin contents (TAC) were from 98.8 to 2132.5 mg/100 g, and cyanidin-3-glucoside was the most abundant anthocyanin in all varieties, with a distribution of 48.8-94.1% of TAC. Antioxidant properties detected by DPPH, FRAP, and ORAC methods all showed wide variations ranging from 4.8 to 65.3 μg/100 mL (expressed as EC(50)), from 17.5 to 105.8 units/g, and from 42.5 to 1834.6 μmol Trolox equivalent/g, respectively. Sixty varieties were classified into four groups by hierarchical clustering analysis, and group 4 consisting of nine varieties had the highest phytochemicals content and antioxidant activity.     

Accumulation of carbohydrates and proline in water-stressed soybean (Glycine max L.)

Abstract

A wide range of metabolites accumulates under water stress depending on certain metabolic alterations. For example, free amino acids, especially free proline, accumulate in response to water stress ((l)). Proline accumulation is closely connected with carbohydrate metabolism. Thus, a carbohydrate requirement for proline accumulation in water-stressed leaves has been reported (2, 3).     

Characterization of nonstarch polysaccharides content from different edible organs of some vegetables, determined by GC and HPLC: comparative study

Content and composition of dietary fiber as nonstarch polysaccharides (NSP) was determined in vegetables belonging to different types of edible organs, using GC and HPLC. Samples analyzed were subterranean organs (radish and leek), leaves (celery, swiss chard, and lettuce), stalks (celery, swiss chard, and asparagus), inflorescence (broccoli), and fruits (tomato, green pepper, and marrow). The results indicate that though the monomeric profile is similar in all these samples quantitative differences were found for neutral sugars and uronic acids among samples of the same type of vegetal organ. The NSP values determined using CG method were in good agreement with HPLC method (R(2) = 0.9005). However, arabinose, mannose, and galactose plus rhamnose are more influenced by the analytical method used than the rest of the monomers in nearly all the samples analyzed. Final values of NSP depend on the method used in celery stalks, broccoli, and green pepper.     

Potential of RAPD analysis of the promiscuous nodulation trait in soybean (Glycine max L)

Inoculation of soybean with cowpea-type rhizobia results in either a promiscuous type of nodulation which produces a plant with functional nodules capable of N fixation and has green leaves without N fertilization or nonpromiscuous type of nodulation which forms nonfunctional (or no nodules) and develops yellow leaves without N fertilization. Promiscuous soybean types are desirable in production regions where the availability of commercial inoculants is limited. Plant breeding efforts to develop improved promiscuous cultivars particularly in developing countries require inexpensive molecular tools for laboratory-based germplasm selection in order to reduce lengthy conventional breeding cycles. The objective of this study was to evaluate the potential of random amplified polymorphic DNA (RAPD) method in identifying promiscuous soybean genotypes. Segregating plant populations created by reciprocal crosses of promiscuous × nonpromiscuous soybean lines were evaluated for useful RAPD markers for promiscuous nodulation. One hundred and sixty random decamers of arbitrary sequences were used in screening for polymorphic loci between the two parental lines. A RAPD pattern which is consistent with the soybean genotypes segregating for promiscuous nodulation was generated by one decamer, OPB06 (5′-TGCTCTGCCC-3′), indicating the potential of using RAPD markers in selecting for promiscuity in soybean breeding programs.     

Phenoxyacetic acid residue incorporation in cell walls of soybean (Glycine max.)

The metabolism of [(14)C] phenoxyacetic acid (POA) and the formation of bound residues were studied in soybean leaves and stems. POA was metabolized to 4-HO-POA and to 4-HO-POA glucoside, and a significant fraction of the radioactivity was incorporated in the cell walls (CW). An extraction procedure of CW polymers was developed to specifically isolate the radioactivity associated with each of them. In leaves, the radioactivity showed a preferential distribution into the hemicelluloses and lignins, while pectins and lignins were the most radioactive CW polymers in stems. The identified bound metabolites were 4-HO-POA, POA, and phenolic residues. The latter and POA were essentially incorporated into the lignin fractions and were linked to the benzylic carbons of lignin monomers. 4-HO-POA, the major bound residue, was more evenly distributed in CW polymers. It was esterified to noncellulosic polysaccharides and lignins, but in the latter, contrary to other POA residues, it was mainly linked at the gamma-carbon of propanoid side-chains of lignin monomers. That type of linkage suggested an enzymatic incorporation of 4-HO-POA in CW, contrary to others residues which have an opportunistic lignin incorporation. That incorporation of 4-HO-POA in CW polymers looks like that of endogenous hydroxycinnamic acids.     

Effect of harvesting and drying conditions on chlorophyll levels of soybean (Glycine max L. Merr)

Chlorophyll in soybean represents a downgrading factor for the crops. Five Brazilian cultivars were harvested between R(6) and R(8) stage of development (Fehr & Caviness scale) and dried at 25 degrees and 40 degrees C. The effect of maturity stages and two drying conditions after harvest were studied to achieve reduction of moisture and chlorophylls to acceptable levels. When seeds were dried at 25 degrees C, even harvesting at early stages of development such as R(6), the green pigments were almost degraded, and 16 ppm of chlorophyll were found at maximum, accompanied by loss of moisture. Moisture and chlorophyll declines as seed matures, but at intermediary stages (R(6)-R(7)), chlorophyll degrades first, so the rate of moisture loss should not be used to predict chlorophyll contents. At 40 degrees C, complete degradation of chlorophyll pigments is only achieved when seeds are swathed from R(7) stage up, otherwise the seed quality could be compromised. Slow drying allows almost complete removal of green pigments, even when seeds are swathed a few days before the physiological maturity stage.     

Glyphosate-resistant and -susceptible soybean (Glycine max) and canola (Brassica napus) dose response and metabolism relationships with glyphosate

Experiments were conducted to determine (1) dose response of glyphosate-resistant (GR) and -susceptible (non-GR) soybean [Glycine max (L.) Merr.] and canola (Brassica napus L.) to glyphosate, (2) if differential metabolism of glyphosate to aminomethyl phosphonic acid (AMPA) is the underlying mechanism for differential resistance to glyphosate among GR soybean varieties, and (3) the extent of metabolism of glyphosate to AMPA in GR canola and to correlate metabolism to injury from AMPA. GR50 (glyphosate dose required to cause a 50% reduction in plant dry weight) values for GR (Asgrow 4603RR) and non-GR (HBKC 5025) soybean were 22.8 kg ae ha-1 and 0.47 kg ha-1, respectively, with GR soybean exhibiting a 49-fold level of resistance to glyphosate as compared to non-GR soybean. Differential reduction in chlorophyll by glyphosate was observed between GR soybean varieties, but there were no differences in shoot fresh weight reduction. No significant differences were found between GR varieties in metabolism of glyphosate to AMPA, and in shikimate levels. These results indicate that GR soybean varieties were able to outgrow the initial injury from glyphosate, which was previously caused at least in part by AMPA. GR50 values for GR (Hyola 514RR) and non-GR (Hyola 440) canola were 14.1 and 0.30 kg ha-1, respectively, with GR canola exhibiting a 47-fold level of resistance to glyphosate when compared to non-GR canola. Glyphosate did not cause reduction in chlorophyll content and shoot fresh weight in GR canola, unlike GR soybean. Less glyphosate (per unit leaf weight) was recovered in glyphosate-treated GR canola as compared to glyphosate-treated GR soybean. External application of AMPA caused similar injury in both GR and non-GR canola. The presence of a bacterial glyphosate oxidoreductase gene in GR canola contributes to breakdown of glyphosate to AMPA. However, the AMPA from glyphosate breakdown could have been metabolized to nonphytotoxic metabolites before causing injury to GR canola. Injury in GR and non-GR canola from exogenous application of AMPA was similar.