Soybean Research Articles

Comparative transcriptome analysis between two different cadmium-accumulating genotypes of soybean (Glycine max) in response to cadmium stress

BackgroundCadmium (Cd) is extremely toxic and non-essential for plants. Different soybean varieties differ greatly in their Cd accumulation ability, but little is known about the underlying molecular mechanisms.ResultsHere, we performed transcriptomic analysis using Illumina pair-end sequencing on root tissues from two soybean varieties (su8, high-Cd-accumulating (HAS) and su7, low Cd-accumulating (LAS)) grown with 0 or 50 μM CdSO4. A total of 18.76 million clean reads from the soybean root samples were obtained after quality assessment and data filtering. After Cd treatment, 739 differentially expressed genes (DEGs; 265 up and 474 down) were found in HAS; however, only 259 DEGs (88 up and 171 down) were found in LAS, and 64 genes were same between the two varieties. Pathway enrichment analysis suggested that after cadmium treatment, the DEGs between LAS and HAS were mainly enriched in glutathione metabolism and plant-pathogen interaction pathways. KEGG analysis showed that phenylalanine metabolism responding to cadmium stress in LAS, while ABC transporters responding to cadmium stress in HAS. Besides we found more differential expressed heavy metal transporters such as ABC transporters and zinc transporters in HAS than LAS, and there were more transcription factors differently expressed in HAS than LAS after cadmium treatment in two soybean varieties, eg. bHLH transcription factor, WRKY transcription factor and ZIP transcription factor.ConclusionsFindings from this study will shed new insights on the underlying molecular mechanisms behind the Cd accumulation in soybean.

Comparing the Potential of Silicon Nanoparticles and Conventional Silicon for Salinity Stress Alleviation in Soybean (Glycine max L.): Growth and Physiological Traits and Rhizosphere/Endophytic Bacterial Communities.

In this study, 20-day-old soybean plants were watered with 100 mL of 100 mM NaCl solution and sprayed with silica nanoparticles (SiO2 NPs) or potassium silicate every 3 days over 15 days, with a final dosage of 12 mg of SiO2 per plant. We assessed the alterations in the plant's growth and physiological traits, and the responses of bacterial microbiome within the leaf endosphere, rhizosphere, and root endosphere. The result showed that the type of silicon did not significantly impact most of the plant parameters. However, the bacterial communities within the leaf and root endospheres had a stronger response to SiO2 NPs treatment, showing enrichment of 24 and 13 microbial taxa, respectively, compared with the silicate treatment, which led to the enrichment of 9 and 8 taxonomic taxa, respectively. The rhizosphere bacterial communities were less sensitive to SiO2 NPs, enriching only 2 microbial clades, compared to the 8 clades enriched by silicate treatment. Furthermore, SiO2 NPs treatment enriched beneficial genera, such as Pseudomonas, Bacillus, and Variovorax in the leaf and root endosphere, likely enhancing plant growth and salinity stress resistance. These findings highlight the potential of SiO2 NPs for foliar application in sustainable farming by enhancing plant-microbe interactions to improve salinity tolerance.

Gamma-aminobutyric acid (GABA) improves salinity stress tolerance in soybean seedlings by modulating their mineral nutrition, osmolyte contents, and ascorbate-glutathione cycle

BackgroundIn plants, GABA plays a critical role in regulating salinity stress tolerance. However, the response of soybean seedlings (Glycine max L.) to exogenous gamma-aminobutyric acid (GABA) under saline stress conditions has not been fully elucidated.ResultsThis study investigated the effects of exogenous GABA (2 mM) on plant biomass and the physiological mechanism through which soybean plants are affected by saline stress conditions (0, 40, and 80 mM of NaCl and Na2SO4 at a 1:1 molar ratio). We noticed that increased salinity stress negatively impacted the growth and metabolism of soybean seedlings, compared to control. The root-stem-leaf biomass (27- and 33%, 20- and 58%, and 25- and 59% under 40- and 80 mM stress, respectively]) and the concentration of chlorophyll a and chlorophyll b significantly decreased. Moreover, the carotenoid content increased significantly (by 35%) following treatment with 40 mM stress. The results exhibited significant increase in the concentration of hydrogen peroxide (H2O2), malondialdehyde (MDA), dehydroascorbic acid (DHA) oxidized glutathione (GSSG), Na+, and Cl− under 40- and 80 mM stress levels, respectively. However, the concentration of mineral nutrients, soluble proteins, and soluble sugars reduced significantly under both salinity stress levels. In contrast, the proline and glycine betaine concentrations increased compared with those in the control group. Moreover, the enzymatic activities of ascorbate peroxidase, monodehydroascorbate reductase, glutathione reductase, and glutathione peroxidase decreased significantly, while those of superoxide dismutase, catalase, peroxidase, and dehydroascorbate reductase increased following saline stress, indicating the overall sensitivity of the ascorbate-glutathione cycle (AsA-GSH). However, exogenous GABA decreased Na+, Cl−, H2O2, and MDA concentration but enhanced photosynthetic pigments, mineral nutrients (K+, K+/Na+ ratio, Zn2+, Fe2+, Mg2+, and Ca2+); osmolytes (proline, glycine betaine, soluble sugar, and soluble protein); enzymatic antioxidant activities; and AsA-GSH pools, thus reducing salinity-associated stress damage and resulting in improved growth and biomass. The positive impact of exogenously applied GABA on soybean plants could be attributed to its ability to improve their physiological stress response mechanisms and reduce harmful substances.ConclusionApplying GABA to soybean plants could be an effective strategy for mitigating salinity stress. In the future, molecular studies may contribute to a better understanding of the mechanisms by which GABA regulates salt tolerance in soybeans.

Cytochrome GmGLY1 is Involved in the Biosynthesis of Glycitein in Soybean.

Isoflavones, the major secondary metabolites of interest due to their benefits to both human and plant health, are exclusively produced by legumes. In this study, we profiled the isoflavone content in dry seeds from 211 soybean [Glycine max (L.) Merr.] accessions grown across five environments. Broad and discernible phenotypic variations were observed among accessions, regions, and years of growth. Twenty-six single-nucleotide polymorphisms (SNPs) associated with the sum of glycitein (GLE), glycitin (GL), 6″-O-acetylglycitin (AGL), and 6″-O-malonylglycitin (MGL) contents were detected in multiple environments via a genome-wide association study (GWAS). These SNPs were located on chromosome 11 (8,148,438 bp to 8,296,956 bp, renamed qGly11-01). Glyma.11g108300 (GmGLY1), a gene that encodes a P450 family protein, was identified via sequence variation analysis, functional annotation, weighted gene coexpression network analysis (WGCNA), and expression profile analysis of candidate gene, and hairy roots transformation in soybean. Overexpression of GmGLY1 increased the glycitein content (GLC) in soybean hairy roots and transgenic seeds, while CRISPR/Cas9-generated mutants exhibited decreased GLC and increased daidzein content (DAC). Haplotype analysis revealed that GmGLY1 allelic variations significantly affect the GLC accumulation. These findings enhance our understanding of genes influencing GLC in soybean and may guide breeding for lines with high and stable GLC.

Identification and Expression Analysis of Soybean (Glycine max L.) Dynamin Genes Reveal Their Involvements in Plant Development and Stress Response

Identification and Expression Analysis of Soybean (Glycine max L.) Dynamin Genes Reveal Their Involvements in Plant Development and Stress Response

Responses of soil aggregation and aggregate‐associated nitrogen to straw return in China: Evidence from a meta‐analysis and a pot experiment

AbstractEnhancing soil structure and soil nitrogen availability is the key to sustainable agricultural development in global cropping systems. Straw return can affect soil aggregation, but the results of recent studies on the influence of straw return on soil aggregation are not consistent, and the distribution and availability of straw‐derived nitrogen in soils are still unclear. Here, a meta‐analysis of the effects of straw return on soil aggregation was conducted based on 57 studies published in China over the past 10 years. Moreover, combined with a pot experiment, the distribution and transfer characteristics of the two main wheat (Triticum aestivum L.)‐preceding crops, corn (Zea mays L.) and soybean (Glycine max L.) straw‐derived nitrogen in the soils were studied by using the 15N‐tracer method in the main wheat‐producing areas of China. 15N‐labeled straw was introduced into soils in pots at rates of 0.3% and 0.5% of the soil dry mass and incubated 60%–70% of the field water capacity throughout the entire growth period of wheat (220 days). A meta‐analysis revealed that straw return significantly improved the mass ratio of large macro‐aggregates (LM%) and small macro‐aggregates (SM%) but significantly decreased the mass ratio of micro‐aggregates (MI%) and silt plus clay‐size particles (CS%), with mean effect sizes of 36.27%, 9.06%, −8.26%, and −21.32%, respectively. The mean weight diameter (MWD) and geometric mean diameter (GMD) also increased by 21.48% and 15.64%, respectively. Compared with SM%, LM% made a greater contribution to the stability of soil aggregates. Moreover, only LM% showed a significant positive correlation with the corresponding aggregate‐associated nitrogen content, which was an important reason for the improvement in soil nitrogen availability after straw return. The positive effect of straw return on soil aggregation was greatest when the soil pH was close to 6.5–7.5, the average annual temperature was greater than 15°C, and the average annual rainfall was close to 800–1000 mm. The results of the pot experiment revealed that the proportions of straw‐derived nitrogen in >2 mm aggregates were 1.21–1.28, 1.50–2.23, and 1.34–1.74 times greater than those in 0.25–2, 0.053–0.25, and <0.053 mm aggregates, respectively. Moreover, the proportion of straw‐derived nitrogen content of aggregates of different particle sizes showed that the proportion of straw used to reach 0.5% of the soil dry weight was greater than 0.3%, which was 1.09–1.66 times greater, and that of soybean straw was significantly greater than that of corn straw, which was 1.50–2.28 times greater. At application rates of 60 g pot−1 and 100 g pot−1 straw, the absorption of soybean straw‐derived nitrogen by wheat was 1.83 and 2.15 times greater than that of corn straw‐derived nitrogen, respectively. In conclusion, straw return effectively improved soil aggregate stability and nitrogen availability, which was closely related to the increase in soil LM%. Soybean straw can stabilize soil aggregates better than corn straw, and its straw‐derived nitrogen is an important nitrogen source for subsequent wheat crops.

137 Impact of dietary soybean-mediated trypsin inhibitor concentrations on nursery pig performance

Abstract Antinutritional factors associated with soybeans and soy products, such as trypsin inhibitor proteins, have been shown to hinder amino acid bioavailability and, consequently, affect the growth performance of pigs. Thus, our objective was to assess the impact of dietary trypsin inhibitor units (TIU; expressed as TIU/mg of feed) on nursery pig performance and health. Sixty barrows [5.56 ± 0.65 kg body weight (BW), Camborough (1050) x 337, (PIC, Hendersonville, TN)], freshly weaned and 19 to 21 d of age were randomly selected and allotted across six dietary treatments (10 pigs/treatment) in a randomized complete block design. All pigs were individually penned with ad libitum access to water and feed. Diets were administered in two phases directly post-weaning, spanning 14 and 28 d, respectively, and the entire test period extended for 42 d. Within each phase, diets were formulated to be isocaloric, with uniform NDF and SID lysine concentrations. In both phases, TIU were incrementally adjusted by the inclusion of soybean meal, raw ground soybeans, soybean oil, and soyhulls to attain a target TIU/mg feed of 0.5, 1, 2, 3, 4, and 6. All diets were analyzed for active TIU/mg. Pig BW and feed disappearance were measured at the start and end of each phase to compute average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F). Fecal consistency was assessed daily in phase 1. Pig was the experimental unit and data were analyzed with the effect of diet, including the linear and quadratic contrasts, evaluating dietary TIU levels. The average analyzed TIU/mg over both diet phases were 0.38, 0.54, 1.85, 3.16, 3.90, and 5.79 TIU/mg diet, respectively. Fecal consistency scores did not differ across diets. At the end of phase 1, BW decreased from 8.7 to 6.9 kg as TIU/mg diet increased from 0.38 to 5.79 (linear P < 0.05). Similarly, by d 42, BW decreased from 25.3 to 15.5 kg with the increase in dietary TIU/mg from 0.38 to 5.79 (linear P < 0.0001). Both phase 1 and 2 showed a decrease in average daily gain (ADG) and G:F as TIU increased (linear P < 0.05). ADFI exhibited a decreasing trend in phase 1 (linear P = 0.079) and a decrease in phase 2 (linear P < 0.05) as dietary TIU increased. No quadratic responses were reported for ADG and G:F. Overall, as TIU increased, ADG, ADFI, and G:F were reduced, with 5.79 TIU/mg feed resulting in a decrease of these parameters by 8 to 22% (linear P < 0.01). In conclusion, increasing TIU levels in the diet had detrimental effects on nursery pig performance. The most significant negative impacts on growth, feed intake, and feed efficiency were observed in diets containing 3.16 to 5.79 TIU/mg feed.

PSI-13 Digestible and metabolizable energy concentrations in soybean meal, fermented soybean meal, and soy protein concentrate fed to nursery pigs

Abstract Accurate information of energy concentrations in protein supplements is critical in formulating diets for nursery pigs. Soybean products are widely used in nursery pig diets due to the high crude protein (CP) concentrations. The objective of the present study was to determine the digestible (DE) and metabolizable energy (ME) in soybean meal (SBM, 48.5% CP), 3 sources of fermented SBM (FSBM-A, FSBM-B, and FSBM-C; 52.6% CP, 55.1% CP, and 49.8% CP, respectively), and soy protein concentrate (SPC, 58.4% CP) fed to nursery pigs. Twelve barrows with an initial body weight of 8.7 kg (standard deviation = 0.5) were individually housed in metabolism crates. A replicated 6 × 4 incomplete Latin square design with 12 animals, 6 experimental diets, and 4 periods was employed. A basal diet contained 96.9% corn as the sole source of energy. The experimental diets were prepared by replacing the basal diet with SBM at 31%, FSBM-A at 27%, FSBM-B at 26%, FSBM-C at 29%, and SPC at 24%. Each period consisted of a 4-d adaptation period and a 4-d collection period. The marker-to-marker procedure was used for the quantitative collection of feces. Urine was collected for 96 h. The difference procedure was employed to calculate the DE and ME values of the soybean ingredients. Additionally, a 3-step in vitro assay was conducted to determine in vitro total tract disappearance of nutrients in the ingredients. The DE concentrations in FSBM-A (4,171 kcal/kg as-fed), FSBM-B (4,111 kcal/kg as-fed), FSBM-C (4,027 kcal/kg as-fed) and SPC (3,999 kcal/kg as-fed) were greater (P < 0.05) than that in SBM (3,724 kcal/kg as-fed). The ME concentrations in FSBM-A (3,883 kcal/kg as-fed) and FSBM-B (3,841 kcal/kg as-fed) were greater (P < 0.05) than that in SBM (3,528 kcal/kg as-fed) but did not differ from those in FSBM-C (3,728 kcal/kg as-fed) or SPC (3,767 kcal/kg as-fed). The DE:gross energy (GE) was greatest (P < 0.05) in FSBM-B but lowest (P < 0.05) in SBM with intermediate ratios for other 3 ingredients whereas the ME:GE and ME:DE were not different among the 5 ingredients. The in vitro total tract disappearance of dry matter and organic matter in SPC was less (P < 0.05) than that in other ingredients. In conclusion, fermented soybean meal and soy protein concentrate contain greater energy concentrations compared with soybean meal.

155 Standardized ileal digestibility of amino acids in soybean meal, fermented soybean meal, and soy protein concentrate fed to nursery pigs

Abstract Accurate information of amino acid (AA) digestibility in protein supplements is critical in formulating diets for nursery pigs. Soybean products are widely used in nursery pig diets due to the high crude protein (CP) concentrations. The objective of the present study was to determine the standardized ileal digestibility (SID) of AA in soybean meal, 3 sources of fermented SBM (FSBM), and soy protein concentrate (SPC) fed to nursery pigs. Ten barrows with an initial body weight of 10.5 kg (standard deviation = 0.9) were surgically fitted with T-cannulas at the distal ileum. The animals were assigned to a replicated 5 × 5 Latin square design with 10 animals, 5 experimental diets, and 5 periods to obtain 10 observations per diet. Five diets were prepared to contain SBM (48.5% CP), 3 sources of FSBM (A, B, and C; 52.6% CP, 55.1% CP, and 49.8% CP, respectively), or SPC (58.4% CP) as the sole source of AA. Each period consisted of 4 d of adaptation period and 3 d of ileal digesta collection period. The values of basal endogenous losses of AA reported in the literature were used to calculate the SID of AA by correcting the apparent ileal digestibility (AID) values. Additionally, a 2-step in vitro procedure modified for nursery pigs was conducted to determine the in vitro ileal disappearance of CP in the 5 ingredients. The AID of all indispensable AA except His and Lys in FSBM-A and FSBM-B was greater (P < 0.05) than that in SBM, whereas AID values for all AA except Trp in SPC did not differ from the values in SBM. The SID of Leu and Trp in FSBM-A and FSBM-B was greater (P < 0.05) than that in SBM or SPC. The SID of all AA in SPC was not different from that in SBM. In vitro ileal disappearance of CP in 3 sources of FSBM was greater (P < 0.001) than that in SBM or SPC. In conclusion, in vitro ileal disappearance of protein was greater in fermented soybean meal compared with soybean meal or soy protein concentrate whereas the standardized ileal digestibility of most amino acids was comparable among the soybean-derived ingredients.

Test of Acceptance and Protein Levels in Soybean Flour Formulation Muffins as Snacks for Young Women with Chronic Energy Deficiency

Chronic energy deficiency in young people is caused by a lack of nutritional intake, such as energy and protein. Consequently, the nutrients required for daily needs are insufficient. This study aims to determine the acceptability test results and protein content in soy flour muffins as a snack for young women with chronic energy deficiency. An experimental study was conducted with 25 participants to assess the acceptability of three muffin formulas, varying in wheat flour to soy flour ratios: 150:0, 90:60, and 80:70. Following processing and acceptability testing, the control and preferred formula were analyzed for protein content in soy flour muffins. The results indicate that the preferred formula among the panelists (DP18) was formula 3, with a wheat flour to soy flour ratio of 80:70, containing a protein content of 10.70%. This formula exhibited an energy density of 4.23 kcal/g and a Protein Energy ratio of 12.31%. Muffins supplemented with 60 g/serving of soy bean can fulfill 10% of daily calorie and protein requirements. Future researchers are encouraged to conduct community-based projects to assess the utility of these muffins in increasing body weight and average arm circumference.

The effect of a fermented soy beverage among patients with localized prostate cancer prior to radical prostatectomy

BackgroundFermented soy products have shown to possess inhibitory effects on prostate cancer (PCa). We evaluated the effect of a fermented soy beverage (Q-Can®), containing medium-chain triglycerides, ketones and soy isoflavones, among men with localized PCa prior to radical prostatectomy.MethodsWe conducted a placebo-controlled, double-blind randomized trial of Q-Can®. Stratified randomization (Cancer of the Prostate Risk Assessment (CAPRA) score at diagnosis) was used to assign patients to receive Q-Can® or placebo for 2–5 weeks before RP. Primary endpoint was change in serum PSA from baseline to end-of-study. We assessed changes in other clinical and pathologic endpoints. The primary ITT analysis compared PSA at end-of-study between randomization arms using repeated measures linear mixed model incorporating baseline CAPRA risk strata.ResultsWe randomized 19 patients, 16 were eligible for analysis of the primary outcome. Mean age at enrollment was 61, 9(56.2%) were classified as low and intermediate risk, and 7(43.8%) high CAPRA risk. Among patients who received Q-Can®, mean PSA at baseline and end-of-study was 8.98(standard deviation, SD 4.07) and 8.02ng/mL(SD 3.99) compared with 8.66(SD 2.71) to 9.53ng/mL(SD 3.03), respectively, (Difference baseline – end-of-study, p = 0.36). There were no significant differences in Gleason score, clinical stage, surgical margin status, or CAPRA score between treatment arms (p > 0.05), and no significant differences between treatment arms in end-of-study or change in lipids, testosterone and FACT-P scores (p > 0.05).ConclusionsShort exposure to Q-Can® among patients with localized PCa was not associated with changes in PSA levels, PCa characteristics including grade and stage or serum testosterone. Due to early termination from inability to recruit, study power, was not achieved.

GmNF-YC4 delays soybean flowering and maturation by directly repressing GmFT2a and GmFT5a expression.

Flowering time and growth period are key agronomic traits which directly affect soybean (Glycine max (L.) Merr.) adaptation to diverse latitudes and farming systems. The FLOWERING LOCUS T (FT) homologs GmFT2a and GmFT5a integrate multiple flowering regulation pathways and significantly advance flowering and maturity in soybean. Pinpointing the genes responsible for regulating GmFT2a and GmFT5a will improve our understanding of the molecular mechanisms governing growth period in soybean. In this study, we identified the Nuclear Factor Y-C (NFY-C) protein GmNF-YC4 as a novel flowering suppressor in soybean under long-day (LD) conditions. GmNF-YC4 delays flowering and maturation by directly repressing the expression of GmFT2a and GmFT5a. In addition, we found that a strong selective sweep event occurred in the chromosomal region harboring the GmNF-YC4 gene during soybean domestication. The GmNF-YC4Hap3 allele was mainly found in wild soybean (Glycine soja Siebold & Zucc.) and has been eliminated from G. max landraces and improved cultivars, which predominantly contain the GmNF-YC4Hap1 allele. Furthermore, the Gmnf-yc4 mutants displayed notably accelerated flowering and maturation under LD conditions. These alleles may prove to be valuable genetic resources for enhancing soybean adaptability to higher latitudes.

Soybean (Glycine max (L.) Merr.) Response to Application of Mineral Nitrogen and Bradyrhizobia on Nitisols of Teppi, Southwest Ethiopia

Soybean (Glycine max (L.) Merr.), an important crop grown for its protein source for humans and livestock, is widely introduced in different parts of Ethiopia. However, the productivity of the crop is far below its potential in the country due to different factors, among which low soil fertility is a major contributor. Hence, this field experiment was conducted with the objective of determining the optimum rate of starter nitrogen (N) and bradyrhizobium inoculation on yield and yield components of soybean in the 2019 and 2020 cropping seasons. Two levels of bradyrhizobia (inoculated and uninoculated) and six levels of starter nitrogen (0, 9, 18, 27, 36, and 54 kg N ha-1) were arranged in a factorial design. The result showed that soybean grain yield increased by about 60 % with inoculation of bradyrhizobia applied with low rates of starter nitrogen fertilizer, regardless of cropping seasons. Application of a nitrogen rate above 18 kg N ha-1 leads to yield decline and has no significant variation from bradyrhizobia inoculation only. Regardless of the cropping seasons, elevated levels of starter nitrogen beyond 27 kg ha-1 suppressed nodulation and nodule dry matter. Starter N at a rate of 9 and 18 kg N ha-1 improved soybean nodulation by 125-130% over control and 95% over bradyrhizobia inoculation alone. Thus, it was recommended to apply bradyrhizobia strains with 9 or 18 kg N ha-1 starter nitrogen for better yield of soybean as well as adequate nitrogen fixation in Nitisols having moderate soil nitrogen levels similar to the Teppi areas.

J-family genes redundantly regulate flowering time and increase yield in soybean

Soybean (Glycine max) is a short-day crop whose flowering time is regulated by photoperiod. The long-juvenile trait extends its vegetative phase and increases yield under short-day conditions. Natural variation in J, the major locus controlling this trait, modulates flowering time. We report that the three J-family genes influence soybean flowering time, with the triple mutant Guangzhou Mammoth-2 flowering late under short days by inhibiting transcription of E1-family genes. J-family genes offer promising allelic combinations for breeding.

Trichoderma harzianum enhances root biomass production and promotes lateral root growth of soybean and common bean under drought stress

AbstractDrought stress (DS) is one of the main environmental stresses that determines crop productivity. It has been estimated that DS depresses over 40%–60% of soybean (Glycine max (L.) Merr.) and common bean (Phaseolus vulgaris L.) production worldwide, respectively. Although different agronomic strategies are sometimes implemented, the current goal in sustainable agriculture could involve the inoculation with native microorganisms to mitigate DS effects. A potential fungal candidate is Trichoderma, which is recognized as a ubiquitous soil inhabitant with growth‐promoting and biocontrol potentiality. However, its potential for mitigating the stress for water deficit is less well‐documented. Our objective was to evaluate the effect of inoculation with native Trichoderma harzianum strains on soybean and common bean growth under contrasting conditions of water availability. Seeds were independently inoculated (or not) with IB‐J15 and IB‐363 strains, and plants were submitted to DS or were kept under optimal irrigation (well‐watered, WW). In both legumes, the most evident effect after being inoculated was the modification of plant root architecture, the increase in root area and the development of lateral roots in plants under WW and DS conditions. In soybean, both Trichoderma strains had a positive inoculation response, both fresh and dry root biomass increased under WW, and remarkably under DS conditions. The main effect was an increase of about 110% in root dry weight under WW and, about 330% in DS in plants inoculated with IB‐J15 strain, meanwhile, plants inoculated with IB‐363 increased root dry weight 60% in WW and 177% in DS conditions. Notably in soybean, the inoculation with both Trichoderma strains increased the root area more than 70% in both WW and DS conditions. Common beans inoculated with IB‐363 under WW conditions, reached a positive inoculation responsiveness of around 247% in shoot dry weight biomass, and under WW both strains increased the root area more than 50%. Further, IB‐363 increased leaf area by 25% in WW and 72% in DS. Additionally, the in vitro co‐culture between both Trichoderma strains and nodulating Rhizobium etli and Bradyrhizobium japonicum E109 showed compatibility between microorganisms, since no inhibition of their growth was observed. We emphasize that plants inoculated with Trichoderma showed better resistance to water deficit, as seen by redistribution of photosynthates, prioritizing mainly, the development of the root system. © 2024 Association of Applied Biologists.

Biochemical characterization and metabolic reprogramming of amino acids in Soybean roots under drought stress.

Amino acids play important roles in stress resistance, plant growth, development, and quality, with roots serving as the primary organs for drought response. We conducted biochemical and multi-omics analyses to investigate the metabolic processes of root amino acids in drought-resistant (HN44) and drought-sensitive (HN65) soybean (Glycine max) varieties. Our analysis revealed an increase in total amino acid content in both varieties, with phenylalanine, proline, and methionine accumulating in both. Additionally, several amino acids exhibited significant decreases in HN65 but slight increases in HN44. Multi-omics association analysis identified 13 amino acid-related pathways. We thoroughly examined the changes in genes and metabolites involved in various amino acid metabolism/synthesis and determined core genes and metabolites through correlation networks. The phenylalanine, tyrosine, and tryptophan metabolic pathways and proline, glutamic acid and sulfur-containing amino acid pathways were particularly important for drought resistance. Some candidate genes, such as ProDH and P4HA family genes, and metabolites, such as O-acetyl-L-serine, directly affected up- and downstream metabolism to induce drought resistance. This study provided a basis for soybean drought resistance breeding.

Cereal rye cover crop termination at or before soybean planting has minimal effect on soybean yield across the midwestern US

ContextInterest is growing among farmers in the Midwestern US region in the potential benefits of establishing cereal rye (Secale cereale L.) as a cover crop. However, they are concerned about the implications and potential trade-offs due to this practice. ObjectiveWe aimed to evaluate the effects of cereal rye cover crop termination at or before soybean planting on soybean (Glycine max [L.] Merr.) seed yield. MethodsField experiments were conducted from 2019 to 2021 across 28 location-years in the Midwestern US. Treatments consisted of no cereal rye, cereal rye termination before soybean planting, and termination at planting. Cereal rye was chemically terminated at each termination timing. Cereal rye biomass and soybean yield were assessed. ResultsDelaying cereal rye termination in soybean systems increased rye biomass, but its impact on soybean yield was inconsistent. Results showed that delayed termination did not reduce soybean seed yield in 25 of 28 location-years compared to a no cover crop treatment. There was no clear evidence indicating that a threshold level of cereal rye biomass accumulation reduced soybean seed yield. ConclusionsOur results suggest that farmers who adopt cereal rye as a winter cover crop in the examined region have a flexible management window for terminating cereal rye, as the timing of termination had minimal effect on soybean seed yield. However, there were no significant soybean seed yield benefits that would justify the associated cost with the use of cover crops. Therefore, conducting long-term studies in the future is highly recommended to better understand how cereal rye cover crops can influence soybean seed yield and soil quality properties over time. Further studies should also investigate the aspect of non-chemical rye management to assess its potential cost-saving effects for farmers adopting this system. ImplicationsThese findings hold several implications for farmers, agronomists, and stakeholders. The increased cereal rye biomass due to delayed termination could offer greater soil benefits. While the inconsistent effects on soybean yield imply flexible termination options for cover crop adoption, the absence of substantial yield benefits underscores the importance of considering both short-term costs and long-term sustainability goals.

Flow Cytometry for Estimating Plant Genome Size: Revisiting Assumptions, Sources of Variation, Reference Standards, and Best Practices

Flow cytometry has been widely used to estimate relative and absolute genome sizes (DNA contents) of plants for more than 50 years. However, the accuracy of these estimates can vary widely because of many factors, including errors in the genome size estimates of reference standards and various experimental methods. The objectives of this study were to reassess genome sizes of commonly used reference standards and quantify sources of variation and error in estimating plant genome sizes that arise from buffers, confounding plant tissues, tissue types, and plant reference standards using both 4′,6-diamidino-2-phenylindole (DAPI) and propidium iodide (PI) fluorochromes. Five separate studies were performed to elucidate these objectives. Revised estimates of genome sizes of commonly used plant reference standards were determined using human male leukocytes as a primary standard with an updated genome size (6.15 pg; 12.14% lower than that of earlier studies) using both DAPI and PI fluorochromes. Comparison of six different buffers (Galbraith’s, LB01, MB01, MgSO4, Otto’s, and Sysmex) resulted in variations in genome size estimates by as much as 18.1% for a given taxon, depending on the buffer–fluorochrome combination. The addition of different confounding plant tissues (representing 10 diverse taxa and associated secondary metabolites) resulted in variations in genome size estimates by as much as 10.3%, depending on the tissue–fluorochrome combination. Different plant tissue types (leaf color/exposure and roots) resulted in a variation in genome size estimates of 10.7%, independent of the fluorochrome. The selection of different internal reference standards introduced an additional variation in genome size estimates of 5.9%, depending on the standard–fluorochrome combination. The choice of fluorochrome (DAPI vs. PI) had one of the largest impacts on genome size estimates and differed by as much as 32.9% for Glycine max ‘Polanka’ when using human male leukocytes as an internal standard. A portion of this variation (∼10.0%) can be attributed to the base pair (bp) bias of DAPI and variations in Guanine-Cytosine (GC):Adenine-Thymine (AT) ratios between the sample and standard. However, as much as 22.9% of the variation in genome size estimates may result from how effectively these fluorochromes stain and report the genome. The combined variation/error from all these factors (excluding variation from bp bias for different fluorochromes, and assuming variations from confounding tissues and tissue types to both result from secondary metabolites) totaled 57.6%. Additional details of how selected factors impact accuracy, precision, and the interaction of these factors are presented. Overall, flow cytometry can be precise, repeatable, and extremely valuable for determining the relative genome size and ploidy of closely related plants when using consistent methods, regardless of fluorochrome. However, accurate determination of the absolute genome size by flow cytometry remains elusive, and estimates of genome size using flow cytometry should be considered gross approximations that may vary by ±29% or more as a function of experimental methods and plant environments. Additional recommendations of best practices are provided.

Flavor formation by amino acid catabolism in low-salt sufu paste, a Chinese fermented soybean food

In this study, the low-salt sufu paste was fermented enhanced by a mixed starter (Pichia fermentans, Kodamaea ohmeri and Lactococcus lactis subsp.) and α-ketoglutarate. Multispecies microbial community is crucial for the flavor formation of sufu paste during post-ripening. Consequently, the primary biochemical pathways of the flavor formation were analyzed using a metagenomic approach in conjunction with gas chromatography mass spectrometry (GC-MS). After post-ripening for 15 d, a total of 86 volatile flavor compounds (VFCs) were tentatively identified, in which 6 compounds were recognized as the main characteristic VFCs. The metagenomics revealed that Actinomucor elegans, Lactobacillus fermentum, Lactococcus lactis subsp., Pichia fermentans, Lactobacillus delbrueckii and Propionibacterium acidipropionici were the dominant species. According to the functional annotation, amino acid metabolisms were identified as the predominant pathways for flavor formation. Among them, aromatic amino acids metabolisms accounted for the highest proportion, up to 41.3%. The VFCs formation pathways mainly involved transamination, decarboxylation, dehydrogenation and oxidation reaction. The amino acid transamination was proposed as a crucial step in VFCs formation, and the corresponding aminotransferases were the key rate-limiting enzymes. These findings have implications for enhancing the flavor quality of sufu paste and elucidating the mechanism of flavor formation in traditional soybean fermented food.

Effect of nutrition management and irrigation methods and schedule on productivity, economics and water-use efficiency in soybean (Glycine max) chickpea (Cicer arietinum) cropping sequence in alluvial soil

A field experiment was conducted during 2011–12 and 2012–13 at Morena, Madhya Pradesh, to study the ef fect of nutrition management, and methods and scheduling of irrigation on soybean [Glycine max (L.) Merr.] chickpea (Cicer arietinum L.) cropping sequence. An irrigation at 0.6 irrigation water:cumulative pan evaporation (IW:CPE) ratio resulted in significantly higher growth, yield attributes, seed yield, economic benefits and water pro ductivity of soybean compared with 0.4 and 0.8 IW:CPE. Similarly, an irrigation at 0.4 IW:CPE ratio significantly in fluenced the yield-attributing characters, seed and straw yields, economic benefits and water productivity of chickpea compared with 0.6 and 0.8 IW:CPE ratios, whereas height and number of branches increased with in creasing IW:CPE ratio. Sprinkler irrigation resulted in significantly higher growth and yield attributes, seed and straw yields, economic benefits and water productivity of both the crops. The irrigation at 0.6 IW:CPE ratio showed 51.3% and 39.0% higher seed of soybean over 0.4 and 0.8 IW:CPE ratio, whereas 0.4 IW:CPE of irrigation yielded 14.5% and 32.5% higher seed of chickpea compared with 0.6 and 0.8 IW:CPE. Mean response of sprinkler irriga tion was recorded 8.3% in soybean and 11.7% in chickpea higher seed yield over check basin irrigation. Likewise, increases in growth and yield attributes, seed yield, water productivity and protein production of soybean and chickpea were noticed with application of 75% recommended dose of fertilizer (RDF) + 2.5 t FYM/ha compared with other nutrition treatments. Addition of 75% RDF + 2.5 t FYM/ha also achieved higher system productivity, net profit and production and economic efficacy. After harvesting of the second crop of chickpea, maximum availability of N, P, K and S was recorded under 0.4 IW:CPE ratio, sprinkler irrigation and application of 75% RDF + 2.5 t FYM/ha compared to other treatments.