Chemical composition of glyphosate-tolerant soybean 40-3-2 grown in Europe remains equivalent with that of conventional soybean (Glycine max L.)

The composition of glyphosate-tolerant (Roundup Ready) soybean 40-3-2 was compared with that of conventional soybean grown in Romania in 2005 as part of a comparative safety assessment program. Samples were collected from replicated field trials, and compositional analyses were performed to measure proximates (moisture, fat, ash, protein, and carbohydrates by calculation), fiber, amino acids, fatty acids, isoflavones, raffinose, stachyose, phytic acid, trypsin inhibitor, and lectin in grain as well as proximates and fiber in forage. The mean values for all biochemical components assessed for Roundup Ready soybean 40-30-2 were similar to those of the conventional control and were within the published range observed for commercial soybean. The compositional profile of Roundup Ready soybean 40-3-2 was also compared to that of conventional soybean varieties grown in Romania by calculating a 99% tolerance interval to describe compositional variability in the population of traditional soybean varieties already on the marketplace. These comparisons, together with the history of the safe use of soybean as a common component of animal feed and human food, lead to the conclusion that Roundup Ready soybean 40-3-2 is compositionally equivalent to and as safe and nutritious as conventional soybean varieties grown commercially.     

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.     

Composition of grain, forage, and processed fractions from second-generation glyphosate-tolerant soybean, MON 89788, is equivalent to that of conventional soybean (Glycine max L.)

Developments in biotechnology and molecular-assisted breeding have led to the development of a second-generation glyphosate-tolerant soybean product, MON 89788. The MON 89788 event was produced by direct transformation of a cp4 epsps (5-enolpyruvylshikimate-3-phosphate synthase) gene cassette derived from Agrobacterium sp. strain CP4 into an elite soybean germplasm known for its superior agronomic characteristics and high yielding property. The purpose of this work was to assess whether the nutrient and antinutrient levels in seed and forage tissues of MON 89788 are comparable to those in the conventional soybean variety, A3244, which has background genetics similar to MON 89788 but does not contain the cp4 epsps gene cassette. Additional conventional soybean varieties currently in the marketplace were also included in the analysis to establish a range of natural variability for each analyte, where the range of variability is defined by a 99% tolerance interval for that particular analyte. Compositional analyses were conducted on forage, seed and four processed fractions from soybeans grown in ten sites across both the United States and Argentina during the 2004-2005 growing seasons. Forage samples were analyzed for levels of proximates (ash, fat, moisture, and protein) and fiber. Seed samples were analyzed for proximates, fiber, antinutrients, and vitamin E. Defatted, toasted (DT) meal was analyzed for proximates, fiber, amino acids, and antinutrients. Refined, bleached, and deodorized (RBD) oil was analyzed for fatty acids and vitamin E. Protein isolate was analyzed for amino acids and moisture. Crude Lecithin was analyzed for phosphatides. Results of the comparisons indicate that MON 89788 is compositionally and nutritionally equivalent to conventional soybean varieties currently in commerce.     

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).     

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.     

Responses to sequential exposure to SO2 and salinity in soybean (Glycine max L.)

Soybean plants (Glycine max L. cv. Buchanan) were subjected to one of three levels of salinity preteatment (with electrical conductivities of 0.7, 4.4 and 6.5 dS m^?1) and then exposed to one of three concentrations of SO₂ (1, 145 and 300 bl l ^?1 for 5 h d^?1), or vice versa. Each stress episode lasted 3 weeks. Both salinity and SO₂ deecreased leaf area, root and shoot dry weight and the fresh weight of root nodules. SO₂ induced an increase in the shoot: root ratio and leaf chlorophyll concentrations. Low salinity pretreatment protected plant growth from SO₂ injury, probably by decreasing SO₂ uptake by increasing stomatal resistance. However, high salinity-treated plants, despite also showing stomatal closure, were severely injured by subsequent SO₂ exposure. Prior exposure to SO₂ caused plants to become more vulnerable to salt injury. Plants pretreated with high SO₂ were killed after 12 days of high salt stress. These data suggest that the compensatory mechanisms and predisposition characteristics of salinity and SO₂ largely depend upon the stress levels used.     

Hydrogen metabolism and nitrogen fixation of soybean (Glycine max. L.) inoculated with different strains ofRhizobium spp.

Summary Hydrogenase activities and N₂-fixing capacities of soybean nodules (Glycine max. cv. Hodgson), inoculated with strains ofBradyrhizobium japonicum andRhizobium fredii from different geographical regions, were measured after 35 days of culture under controlled conditions. Of the strains tested, 47% induced nodules with bacteroids which recycled H₂. The data obtained suggest that H₂-recycling ability is not a major factor influencing early N₂-fixation which depends essentially on the precocity and intensity of the initial nodulation.     

Foliar fertilization of soybeans (Glycine max L.)

Abstract

The effects of foliar fertilizer applications to soybeans during seed‐filling were examined using a complete factorial design with four levels each of nitrogen (N), phosphorus plus potassium (P+K) and sulfur (S). Hodgson soybeans were planted in 76‐cm rows on a Piano silt loam (Typic Argiudoll) in 1976 and 1977. Four fertilizer spray applications were made at 7‐ to 10‐day intervals beginning at stage R₄ ². The application of N generally increased yield, seed weight, and percent N in the grain both years of the experiment. Phosphorus, K, and S had little influence on the parameters measured. Leaf burn after each fertilizer application was significantly increased by most levels of fertilizer addition.     

Sulfur uptake by soybeans (Glycine max L.)

Abstract

Sulfur accumulation in young soybean plants tended to follow the pattern reported for P differing only in quantity. Soybean stems tended to have a more constant S concentration over time than did leaves or petioles.

The nutrient uptake pattern of a crop provides clues to more efficient management of plant nutrients. The recent reports of increased yields of soybeans due to foliar fertilization would seem to be a culmination of previous work done in Iowa on nutrient uptake patterns (1, 2, 3).

In the work reported to date there are no data which illustrate patterns of sulfur uptake by soybeans during the growing season. The work reported here was an attempt to determine the pattern of S uptake by soybeans during early growth stages.     

Oxalate and phytate concentrations in seeds of soybean cultivars [Glycine max (L.) Merr.

This study analyzed soybean seeds from 116 cultivars for total, insoluble, and soluble oxalate (Ox), phytate (InsP6), calcium (Ca), and magnesium (Mg) because of their potential beneficial or harmful effects on human nutrition. These cultivars were divided into four groups (A-D) on the basis of the year and geographic location where they were grown. Oxalate concentration ranged from about 82 to 285 mg/100 g of dry seed. The InsP6 concentration ranged from 0.22 to 2.22 g/100 g of dry seed. There was no correlation between Ox and InsP6 within or among the four groups of cultivars. There was a significant correlation between total Ox and Ca, but not Mg, in group D cultivars (r = 0.3705; p < 0.0005). No significant relationship was found in the group A-C cultivars. Eleven group D cultivars had InsP6 less than 500 mg/100 g, but all had total Ox of 130 mg/100 g or greater. Five cultivars from groups A-C had relatively low InsP6 (group B; < or =1.01 g/100 g) and low Ox (<140 mg/100 g). These cultivars could be useful for producing soy foods beneficial to populations at risk for kidney stones and for improved mineral bioavailability. The Ox and InsP6 concentrations of the cultivars indicate that choosing specific parents could generate seeds in succeeding generations with desirable Ox and InsP6 concentrations.     

Potassium fertilization effects on isoflavone concentrations in soybean [Glycine max (L.) Merr.

Soybean isoflavone concentrations vary widely, but the contribution of soil fertility and nutrient management to this variability is unknown. Field experiments from 1998 to 2000 on soils with low to high exchangeable potassium (K) concentrations evaluated K application and placement effects on isoflavone concentrations and composition of soybean in various tillage and row-width systems. Soybean seed yield and concentrations of daidzein, genistein, glycitein, leaf K, and seed K were measured. Significant increases in daidzein, genistein, and total isoflavone were observed with direct deep-banded K or residual surface-applied K on low-K soils. Positive effects of K fertilization on isoflavones were less frequent on medium- to high-testing K soils. Both individual and total isoflavones were often positively correlated with seed yield, leaf K, and seed K on low-K soils. Appropriate K management could be an effective approach to increase isoflavone concentrations for soybeans produced on low- to medium-K soils.     

Inoculation with indigenous rhizobial isolates enhanced nodulation,growth, yield and protein content of soybean (Glycine max L.) at different agro-climatic regions in Ethiopia

Abstract

Soybean cultivation in Ethiopia is dominated by smallholder farmers who use little or no inputs, often resulting in low yields. The use of effective rhizobia strains was considered as an ecologically and environmentally sound approach for soybean production. Field experiments were conducted during 2015/16 cropping seasons at two different agro-climatic regions in Ethiopia to investigate the effectiveness of local soybean isolates for improving nodulation, growth, yield and quality of soybean. Ten treatments comprising of seven indigenous rhizobia isolates, one exotic strain, nitrogen fertilized treatment and uninoculated control were arranged in randomized complete block design in three replications. Results of the experiment revealed that nodule number and nodule dry weight significantly increased from nil in the uninoculated control to 14–34 and 110–521?mg plant^?1, respectively due to inoculation with different isolates. Furthermore, inoculation significantly increased shoot dry weight by 24–46%, shoot nitrogen concentration by 20–30%, shoot N content by 29–49%, plant height by 14–41%, pods per plant by 12–38%, seeds per pod by 7–19%, thousand seed weight by 15–24%, grain yield by 22–115% and protein content by 7–39% compared with the uninoculated control. Generally, isolates Jm-1-Bo, As-5-Aw, Bk-3-Aw, Cw-6-Aw and MAR 1495 performed better than the others in most yield parameters at both locations of which Jm-1-Bo and As-5-Aw were the local isolates performing best irrespective of location, and were superior to the effective exotic standard strain. Therefore, isolates Jm-1-Bo, As-5-Aw and Bk-3-Aw could be utilized as candidates for inoculant production at large scale in areas with similar agroecology.     

Correlations of oil and protein with isoflavone concentration in soybean [Glycine max (L.) Merr.

Twelve isoflavones were detected by high-performance liquid chromatography in seeds of 17 soybean [Glycine max (L.) Merrill] cultivars grown at three locations. 6' '-O-Malonyldaidzin and 6' '-O-malonylgenistin together constituted 71-81% of total isoflavones, which ranged in concentration from 2038 to 9514 microg/g and averaged 5644 microg/g across locations and cultivars. The total as well as several individual isoflavones had a moderate negative correlation with oil across locations and cultivars. Six cultivars had a moderate or strong negative correlation of total isoflavones with oil. Five cultivars had a moderate or strong positive correlation of total isoflavones with protein. These results suggest that judicious selection of germplasm for soybean breeding may facilitate development of soybean lines with desirable isoflavone concentrations.     

Isolation and determination of anthocyanins in seed coats of black soybean (Glycine max (L.) Merr.).

Anthocyanin pigments in seed coats of black soybean (Glycine max (L.) Merr.) were extracted with 1% HCl-CH(3)OH, and the crude anthocyanin extract was purified by Shepadex LH-20 and Lichroprep RP-18 open-column chromatography. Three major anthocyanins were isolated, and their chemical structures were identified by spectroscopic methods (UV-visible, FABMS, (1)H and (13)C NMR, and by TLC). The complete structures of these anthocyanins were elucidated as delphinidin-3-glucoside, cyanidin-3-glucoside, and petunidin-3-glucoside. Among them, petunidin-3-glucoside was identified as a new anthocyanin in black soybeans. On the basis of RP-HPLC with a UV-vis detector, the contents of delphinidin-3-glucoside, cyanidin-3-glucoside, petunidin-3-glucoside, and total anthocyanins in seed coats of 10 black soybeans were found in the ranges of 0-3.71, 0.94-15.98, 0-1.41, and 1.58-20.18 mg/g, respectively. The results obtained in this study imply that the seed coats of black soybean can be used as a good source for cyanidin-3-glucoside and delphinidin-3-glucoside.     

Analysis of isoflavones and phenolic compounds in Korean soybean [Glycine max (L.) Merrill] seeds of different seed weights

The seeds of 322 Korean soybean varieties were collected from six different cultivated sites in Korea and classified into three groups based on the 100-seed weight as small, medium, and large. Seeds were analyzed for their concentrations of isoflavones and phenolic compounds. The total average isoflavones in soybean cultivated at Iksan (2.840 micromol g(-1)) and phenolic compounds in soybean grown at Yeoncheon (9.216 micromol g(-1)) and Iksan (9.154 micromol g(-1)) were significantly different (p<0.05). In small and medium seeds of soybeans cultivated at Yeoncheon, Yesan, and Milyang high levels of isoflavones were obtained, whereas soybeans grown in Chuncheon showed the lowest isoflavone concentrations. However, isoflavone concentrations in the large seeds of soybean cultivated at Chuncheon showed the highest level. The soybean cultivated at Yeoncheon had high levels of phenolic compounds in small, medium, and large seeds, whereas the soybean grown at Chuncheon had the lowest. On the other hand, the phenolic concentrations of large soybean cultivated at Milyang were the least. At Yeoncheon, Yesan, and Milyang, the total isoflavone and phenolic compounds levels related to their seed size was significantly different (p<0.05), whereas in the soybean of different sizes cultivated at Chuncheon, the relationship to their seed size was not significantly different. The relationships of total isoflavones and phenolic compounds of small and medium soybean seeds were significantly higher than that of large soybean seeds. The hydroxybenzoic acid group in all sizes of seeds cultivated at six sites in Korea was the major phenolic compound, followed by flavonoid and hydroxycinnamic acid. The total isoflavone concentration was positively correlated with acetylglycoside and negatively correlated with malonylglycoside in the small soybean seeds cultivated at Yeoncheon. In medium soybean seeds cultivated at Yeoncheon, a significantly positive correlation was found between acetylglycoside and glycoside, between aglycone and glycoside, and between aglycone and acetylglycoside, whereas a significantly negative correlation was shown between malonylglycoside and glycoside, between acetylglycoside and malonylglycoside, and between aglycone and malonylglycoside. In large soybean seeds cultivated at Chuncheon, significantly positive and negative correlations were similar to those of medium seeds. The results presented here can improve the understanding of the relationships among the concentrations of individual chemical compounds and each chemical compound group and total chemical compounds in soybeans of different seed sizes from different cultivated sites.     

Effects of Rhizobium inoculation and magnesium application on growth and nodulation of soybean (Glycine max L.)

Abstract

Magnesium (Mg) deficiency is one of the major nutritional problems in tropic and subtropic areas, where the most soils are acidic. In this study, the effects of Mg application and Bradyrhizobium inoculation on growth, nodulation, symbiotic nitrogen (N) fixation as well as N nutrition status in soybean (Glycine max L.) were investigated in hydroponics under greenhouse conditions. With the increase of Mg up to 0.75?mM at low N and up to 0.5?mM at high N solutions, the dry weights of shoots, roots, and pod grain yield in soybean were increased, while further increase in Mg supply inhibited soybean growth. The availability of Mg was found to entail an improved uptake of N by plants and nodulation process in the root by Bradyrhizobium. Inoculation with rhizobial inoculants not only formed many nodules, but also increased soybean shoot, root biomass and yield, as well as plant N nutrient status.     

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.     

Rapid and reversible nitrate inhibition of nodule growth and N2 fixation activity in soybean (Glycine max (L.) Merr.)

Nodulated soybean (Glycine max. (L) Merr. cv. Williams) plants were hydroponically cultured, and various combinations of 1-week culture with 5 or 0 mm nitrate were applied using 13-d-old soybean seedlings during three successive weeks. The treatments were designated as 0-0-0, 5-5-5, 5-5-0, 5-0-0, 5-0-5, 0-5-5, and 0-0-5, where the three sequential numbers denote the nitrate concentration (mm) applied in the first-second-third weeks. The size of the individual nodule was measured periodically using a slide caliper. All the plants were harvested after measurement of the acetylene reduction activity (ARA) at the end of the treatments. In the 0-0-0 treatment, the nodules grew continuously during the treatment period. Individual nodule growth was immediately suppressed after 5 mm nitrate supply. However, the nodule growth rapidly recovered by changing the 5 mm nitrate solution to a 0 mm nitrate solution in the 5-0-0 and 5-5-0 treatments. In the 5-0-5 treatment, nodule growth was completely inhibited in the first and the third weeks with 5 mm nitrate, but the nodule growth was enhanced in the second week with 0 mm nitrate. The nodule growth response to 5 mm nitrate was similar between small and large size nodules. After the 5-5-5, 5-0-5, 0-0-5, and 0-5-5 treatments, where the plants were cultured with 5 mm nitrate in the last third week, the ARA per plant was significantly lower compared with the 0-0-0 treatment. On the other hand, the ARA after the 5-0-0 and 5-5-0 treatments was relatively higher than that after the 0-0-0 treatment, possibly due to the higher photosynthate supply associated with the vigorous vegetative growth of the plants supplemented with nitrate nitrogen. It is concluded that both soybean nodule growth and N₂ fixation activity sensitively responded to the external nitrate level, and that these parameters were reversibly regulated by the current status of nitrate in the culture solution, possibly through sensing of the nitrate concentration in roots and / or nodules.     

Field performance of three Bradyrhizobium japonicum strains with two soybean (Glycine max. L.) cultivars

Summary A field experiment was condutced in a clay loam soil to study the performance of three Bradyrhizobium japonicum strains; USDA 110, USDA 138 and TAL 379, in relation to their N₂-fixing potential and competitiveness on two soybean cultivars (Clark and Calland). Inoculation of soybean cultivars with these strains, either singly or in combination, induced significant increases in plant dry weight, N₂ fixation and seed yields. However, no significant differences were found between the rhizobial strains and/or their mixtures in N₂ fixation and increased seed yield for both cultivars. The two soybean cultivars gave similar responses to inoculation. No significant differences in seed yield were observed between Clark and Calland cultivars. The interaction between inoculant strain and soybean cultivar was not significant. The competition between strains for nodulation was assessed. Strain USDA 110 was the most competitive, followed by USDA 138. Strain TAL 379 was always less competitive on both cultivars. The incidence of double-strain occupancy of nodules varied from 8% to 40%.