Bowman-Birk Inhibitor Mutants of Soybean Generated by CRISPR-Cas9 Reveal Drastic Reductions in Trypsin and Chymotrypsin Inhibitor Activities.

Despite the high quality of soybean protein, raw soybeans and soybean meal cannot be directly included in animal feed mixtures due to the presence of Kunitz (KTi) and Bowman-Birk protease inhibitors (BBis), which reduces animal productivity. Heat treatment can substantially inactivate trypsin and chymotrypsin inhibitors (BBis), but such treatment is energy-intensive, adds expense, and negatively impacts the quality of seed proteins. As an alternative approach, we have employed CRISPR/Cas9 gene editing to create mutations in BBi genes to drastically lower the protease inhibitor content in soybean seed. Agrobacterium-mediated transformation was used to generate several stable transgenic soybean events. These independent CRISPR/Cas9 events were examined in comparison to wild-type plants using Sanger sequencing, proteomic analysis, trypsin/chymotrypsin inhibitor activity assays, and qRT-PCR. Collectively, our results demonstrate the creation of an allelic series of loss-of-function mutations affecting the major BBi gene in soybean. Mutations in two of the highly expressed seed-specific BBi genes lead to substantial reductions in both trypsin and chymotrypsin inhibitor activities.

Complete genome sequence of Bacillus velezensis strain Ag109, a biocontrol agent against plant-parasitic nematodes and Sclerotinia sclerotiorum.

Soybean is the main oilseed cultivated worldwide. Even though Brazil is the world's largest producer and exporter of soybean, its production is severely limited by biotic factors. Soil borne diseases are the most damaging biotic stressors since they significantly reduce yield and are challenging to manage. In this context, the present study aimed to evaluate the potential of a bacterial strain (Ag109) as a biocontrol agent for different soil pathogens (nematodes and fungi) of soybean. In addition, the genome of Ag109 was wholly sequenced and genes related to secondary metabolite production and plant growth promotion were mined. Ag109 showed nematode control in soybean and controlled 69 and 45% of the populations of Meloidogyne javanica and Pratylenchus brachyurus, respectively. Regarding antifungal activity, these strains showed activity against Macrophomia phaseolina, Rhizoctonia solani, and Sclerotinia sclerotiorum. For S. sclerotiorum, this strain increased the number of healthy plants and root dry mass compared to the control (with inoculation). Based on the average nucleotide identity and digital DNA-DNA hybridization, this strain was identified as Bacillus velezensis. Diverse clusters of specific genes related to secondary metabolite biosynthesis and root growth promotion were identified, highlighting the potential of this strain to be used as a multifunctional microbial inoculant that acts as a biological control agent while promoting plant growth in soybean.

Genome-Wide Identification of Members of the Soybean CBL Gene Family and Characterization of the Functional Role of GmCBL1 in Responses to Saline and Alkaline Stress.

Calcium ions function as key messengers in the context of intracellular signal transduction. The ability of plants to respond to biotic and abiotic stressors is highly dependent on the calcineurin B-like protein (CBL) and CBL-interacting protein kinase (CIPK) signaling network. Here, a comprehensive effort was made to identify all members of the soybean CBL gene family, leading to the identification of 15 total genes distributed randomly across nine chromosomes, including 13 segmental duplicates. All the GmCBL gene subfamilies presented with similar gene structures and conserved motifs. Analyses of the expression of these genes in different tissues revealed that the majority of these GmCBLs were predominantly expressed in the roots. Significant GmCBL expression and activity increases were also observed in response to a range of stress-related treatments, including salt stress, alkaline stress, osmotic stress, or exposure to salicylic acid, brassinosteroids, or abscisic acid. Striking increases in GmCBL1 expression were observed in response to alkaline and salt stress. Subsequent analyses revealed that GmCBL1 was capable of enhancing soybean salt and alkali tolerance through the regulation of redox reactions. These results offer new insight into the complex mechanisms through which the soybean CBL gene family regulates the responses of these plants to environmental stressors, highlighting promising targets for efforts aimed at enhancing soybean stress tolerance.

Foliar selenium biofortification of soybean: the potential for transformation of mineral selenium into organic forms.

Introduction: Selenium (Se) deficiency, stemming from malnutrition in humans and animals, has the potential to disrupt many vital physiological processes, particularly those reliant on specific selenoproteins. Agronomic biofortification of crops through the application of Se-containing sprays provides an efficient method to enhance the Se content in the harvested biomass. An optimal candidate for systematic enrichment, guaranteeing a broad trophic impact, must meet several criteria: (i) efficient accumulation of Se without compromising crop yield, (ii) effective conversion of mineral Se fertilizer into usable organically bound Se forms (Seorg), (iii) acceptance of a Se-enriched crop as livestock feed, and (iv), interest from the food processing industry in utilization of Se-enriched outputs. Hence, priority should be given to high-protein leafy crops, such as soybean. Methods: A three-year study in the Czech Republic was conducted to investigate the response of field-grown soybean plants to foliar application of Na2SeO4 solutions (0, 15, 40, and 100 g/ha Se); measured outcomes included crop yield, Se distribution in aboveground biomass, and the chemical speciation of Se in seeds. Results and Discussion: Seed yield was unaffected by applied SeO4 2-, with Se content reaching levels as high as 16.2 mg/kg. The relationship between SeO4 2-dose and Se content in seeds followed a linear regression model. Notably, the soybeans demonstrated an impressive 73% average recovery of Se in seeds. Selenomethionine was identified as the predominant species of Se in enzymatic hydrolysates of soybean, constituting up to 95% of Seorg in seeds. Minor Se species, such as selenocystine, selenite, and selenate, were also detected. The timing of Se spraying influenced both plant SeO4 2- biotransformation and total content in seeds, emphasizing the critical importance of optimizing the biofortification protocol. Future research should explore the economic viability, long-term ecological sustainability, and the broad nutritional implications of incorporating Se-enriched soybeans into food for humans and animals.

Decoction derived from Allium ascalonicum L. bulbs and Sojae Semen Praeparatum alleviates wind-cold-type common cold via Nrf2/HO-1 pathway and modulation of Lactobacillus murinus level.

Background: Cong-Chi decoction (CCD) is made using Allium ascalonicum L. (shallot) bulbs and Sojae Semen Praeparatum (SSP). Shallot bulbs and SSP are both used regularly in traditional Chinese medicine; however, there are no recent pharmacological studies on their synergistic effects. Despite their roles in the treatment of the common cold for thousands of years, their pharmacological mechanisms of action against wind-cold-type common cold are yet to be explored comprehensively. Methods: A mouse model was standardized using wind-cold modeling equipment to study the anti-inflammatory, antioxidant, and antiapoptotic effects of CCD. Then, 16S rRNA sequencing was employed to analyze the association between Lactobacillus murinus and changes in body temperature. Additionally, the antipyretic effects of L. murinus were validated via animal experiments. Results: The results indicate that CCD improves the symptoms of wind-cold by reducing fever, levels of pro-inflammatory factors, and cellular apoptosis, as well as increasing the blood leukocyte and lymphocyte counts, thereby alleviating lung tissue damage. The effects of CCD are mediated by upregulation of pulmonary Nrf2 and HO-1 expressions, thereby reducing oxidative damage in the lungs, in addition to other anti-inflammatory mechanisms. Furthermore, CCD increases the abundance of L. murinus in the intestinal tract. The animal experiments confirm that L. murinus ameliorates fever in mice. Conclusion: CCD exhibits remarkable antioxidant and anti-inflammatory properties for effectively treating wind-cold-type common cold. Furthermore, its regulatory effects on L. murinus represent a novel mechanism for product development.

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.

Supplemental Silicon and Boron Alleviates Aluminum-Induced Oxidative Damage in Soybean Roots.

Aluminum (Al) toxicity in acidic soils is a major abiotic stress that negatively impacts plant growth and development. The toxic effects of Al manifest primarily in the root system, leading to inhibited root elongation and functionality, which impairs the above-ground organs of the plant. Recent research has greatly improved our understanding of the applications of small molecule compounds in alleviating Al toxicity. This study aimed to investigate the role of boron (B), silicon (Si), and their combination in alleviating Al toxicity in soybeans. The results revealed that the combined application significantly improved the biomass and length of soybean roots exposed to Al toxicity compared to B and Si treatments alone. Our results also indicated that Al toxicity causes programmed cell death (PCD) in soybean roots, while B, Si, and their combination all alleviated the PCD induced by Al toxicity. The oxidative damage induced by Al toxicity was noticeably alleviated, as evidenced by lower MAD and H2O2 accumulation in the soybean roots treated with the B and Si combination. Moreover, B, Si, and combined B and Si significantly enhanced plant antioxidant systems by up-regulating antioxidant enzymes including CAT, POD, APX, and SOD. Overall, supplementation with B, Si, and their combination was found to alleviate oxidative damage and reduce PCD caused by Al toxicity, which may be one of the mechanisms by which they alleviate root growth inhibition due to Al toxicity. Our results suggest that supplementation with B, Si, and their combination may be an effective strategy to improve soybean growth and productivity against Al toxicity.

Identification of Gene-Allele System Conferring Alkali-Tolerance at Seedling Stage in Northeast China Soybean Germplasm.

Salinization of cultivated soils may result in either high salt levels or alkaline conditions, both of which stress crops and reduce performance. We sampled genotypes included in the Northeast China soybean germplasm population (NECSGP) to identify possible genes that affect tolerance to alkaline soil conditions. In this study, 361 soybean accessions collected in Northeast China were tested under 220 mM NaHCO3:Na2CO3 = 9:1 (pH = 9.8) to evaluate the alkali-tolerance (ATI) at the seedling stage in Mudanjiang, Heilongjiang, China. The restricted two-stage multi-locus model genome-wide association study (RTM-GWAS) with gene-allele sequences as markers (6503 GASMs) based on simplified genome resequencing (RAD-sequencing) was accomplished. From this analysis, 132 main effect candidate genes with 359 alleles and 35 Gene × Environment genes with 103 alleles were identified, explaining 90.93% and 2.80% of the seedling alkali-tolerance phenotypic variation, respectively. Genetic variability of ATI in NECSGP was observed primarily within subpopulations, especially in ecoregion B, from which 80% of ATI-tolerant accessions were screened out. The biological functions of 132 candidate genes were classified into eight functional categories (defense response, substance transport, regulation, metabolism-related, substance synthesis, biological process, plant development, and unknown function). From the ATI gene-allele system, six key genes-alleles were identified as starting points for further study on understanding the ATI gene network.

Optimizing the Release Pattern of Telenomus podisi for Effective Biological Control of Euschistus heros in Soybean.

An augmentative biological control program using the egg parasitoid Telenomus podisi Ashmead (Hymenoptera: Platygastridae) is a promising tool for the management of the brown stink bug, Euschistus heros (Fabricius) (Hemiptera: Pentatomidae) in soybeans. The T. podisi are released as adults or pupae within lab-reared E. heros eggs. Because of the small size of the parasitoid and potentially limited dispersal ability, determining the optimal release pattern is critical for biological control of the target pest. This study used sentinel E. heros eggs to investigate T. podisi dispersal within soybean crops during two distinct phenological stages: the beginning of flowering (Vn-R1) and the grain-filling phase (R5-R6). Data were analyzed using semi-variograms and kriging maps. The results indicate significant differences in parasitism rates between the two plant growth stages and among different matrices. The maximum dispersal range for T. podisi was calculated at 39.0 m in the Vn-R1 stage with a maximum parasitism rate of 42%, while in the R5-R6 stage, the maximum dispersal range was calculated to be 30.9 m with a maximum parasitism of 73%. Therefore, it is recommended that release points for T. podisi be spaced no further than 30 m apart. These results provide valuable insights for future research and applications in biological control strategies, including adjustment of the logistics and release technique depending upon the crop phenological stage.

Machine learning in the classification of asian rust severity in soybean using hyperspectral sensor.

Traditional monitoring of asian soybean rust severity is a time- and labor-intensive task, as it requires visual assessments by skilled professionals in the field. Thus, the use of remote sensing and machine learning (ML) techniques in data processing has emerged as an approach that can increase efficiency in disease monitoring, enabling faster, more accurate and time- and labor-saving evaluations. The aims of the study were: (i) to identify the spectral signature of different levels of Asian soybean rust severity; (ii) to identify the most accurate machine learning algorithm for classifying disease severity levels; (iii) which spectral input provides the highest classification accuracy for the algorithms; (iv) to determine a sample size of leaves that guarantees the best accuracy for the algorithms. A field experiment was carried out in the 2022/2023 harvest in a randomized block design with a 6x3 factorial scheme (ML algorithms x severity levels) and four replications. Disease severity levels assessed were: healthy leaves, 25 % severity, and 50 % severity. Leaf hyperspectral analysis was carried out over a wide range from 350 to 2500 nm. From this analysis, 28 spectral bands were extracted, seeking to distinguish the spectral signature for each severity level with the least input dataset. Data was subjected to machine learning analysis using Artificial Neural Network (ANN), REPTree (DT) and J48 decision trees, Random Forest (RF), and Support Vector Machine (SVM) algorithms, as well as a traditional classification method (Logistic Regression - LR). Two different input datasets were tested for each algorithm: the full spectrum (ALL) provided by the sensor and the 28 spectral bands (SB). Tests with different sample sizes were also conducted to investigate the algorithms' ability to detect severity levels with a reduced sample size. Our findings indicate differences between the spectral curves for the severity levels assessed, which makes it possible to differentiate between healthy plants with low and high severity using hyperspectral sensing. SVM was the most accurate algorithm for classifying severity levels by using all the spectral information as input. This algorithm also provided high classification accuracy when using smaller leaf samples. This study reveals that hyperspectral sensing and the use of ML algorithms provide an accurate classification of different levels of Asian rust severity, and can be powerful tools for a more efficient disease monitoring process.

Community development in the production of concentrated flourhigh in amino acids made from a combination of eel and tempe / Desarrollo comunitario en la producción de harina concentrada rica en aminoácidos a partir de una combinación de anguila y tempe

Introduction and Objectives: To date, there are no known supplement products made from a combination of eel and tempe. The development of concentrate from eels in combination with tempe (ETF) aims to create supplements containing the essential amino acid L-arginine, which has many proven health benefits. Methods: The community empowerment was held from June to July 2023 at Cangkringan, Sleman, Yogyakarta. The main agendas consisted of ETF training production and the cooking creation of ETF-based food. Aside from that, there were several secondary agendas such as food halal socialization, accessories design training, patchwork utilization training, computer and Microsoft Office training, English language education, public speaking class, Al-Qur’an and miscellaneous education for children, community service, mutual cinema, and competitions for the community. Results: The community development program in the production of high-amino acid concentrated ETF flour has succeeded in achieving the three main objectives of the program, namely functional product innovation, empowerment of micro, small, and medium enterprises and local communities, as well as increasing demand for local commodities, showing the importance of collaboration between the government, community, and private sector in supporting the development of local products that are economically and health-beneficial and can be used as examples to share similar initiatives in other areas.(AU)

Enhancement of soybean tolerance to water stress through regulation of nitrogen and antioxidant defence mechanisms mediated by the synergistic role of salicylic acid and thiourea.

Water stress (WS) poses a significant threat to global food and energy security by adversely affecting soybean growth and nitrogen metabolism. This study explores the synergistic effects of exogenous salicylic acid (SA, 0.5 mM) and thiourea (TU, 400 mg L-1), potent plant growth regulators, on soybean responses under WS conditions. The treatments involved foliar spraying for 3 days before inducing WS by reducing soil moisture to 50% of field capacity, followed by 2 weeks of cultivation under normal or WS conditions. WS significantly reduced plant biomass, chlorophyll content, photosynthetic efficiency, water status, protein content, and total nitrogen content in roots and leaves. Concurrently, it elevated levels of leaf malondialdehyde, H2O2, proline, nitrate, and ammonium. WS also triggered an increase in antioxidant enzyme activity and osmolyte accumulation in soybean plants. Application of SA and TU enhanced the activities of key enzymes crucial for nitrogen assimilation and amino acid synthesis. Moreover, SA and TU improved plant growth, water status, chlorophyll content, photosynthetic efficiency, protein content, and total nitrogen content, while reducing oxidative stress and leaf proline levels. Indeed, the simultaneous application of SA and TU demonstrated a heightened impact compared to their separate use, suggesting a synergistic interaction. This study underscores the potential of SA and TU to enhance WS tolerance in soybean plants by modulating nitrogen metabolism and mitigating oxidative damage. These findings hold significant promise for improving crop productivity and quality in the face of escalating water limitations due to climate change.

Glyphosate hormesis induced by treatment via seed stimulates the growth and biomass accumulation in soybean seedlings.

Glyphosate hormesis, identified as a potential means to enhance crop yields, encounters practical constraints because it is typically assessed through foliar applications. The expression and extend of hormesis in this approach are influenced by unpredictable environmental conditions, highlighting the need to explore alternative glyphosate application methods, such as seed treatment. This study aimed to assess glyphosate hormesis on growth rates and biomass accumulation in seedlings soybean cultivars. Two dose-response experiments [doses from 0 to 2880 g acid equivalent (ae) ha-1], one via foliar and one via seed, were conducted on three soybean cultivars [one non-glyphosate-resistant (NGR) and two glyphosate-resistant (GR, one RR and one RR2)]. In a subsequent experiment, three safe glyphosate doses (0, 90 and 180 g ae ha-1) applied via seed were evaluated on four soybean cultivars (two RR and two RR2). For foliar applications, the range of glyphosate doses increasing growth rates and dry biomass by 12-28 % were 5.6-45 g ae ha-1 for the NGR cultivar, of 45-720 g ae ha-1 for RR and of 11.25-180 g ae ha-1 for RR2. In the seed treatment, biomass increases of 16-60 % occurred at 45-180 g ae ha-1 for the NGR and RR cultivars, and 90-360 g ae ha-1 for RR2. Glyphosate doses of 90 and 180 g ae ha-1, applied via seeds, provided greater growth and biomass accumulation for the RR and RR2 soybean cultivars. Both foliar and seed applications of glyphosate increased growth and biomass accumulation in soybean cultivars, with seed treatments showing greater and more consistent enhancements. These findings propose practical and viable alternative for harnessing glyphosate hormesis to facilitate the early development of soybeans and potentially enhance crop yield.

Multi-omics-driven advances in the understanding of triacylglycerol biosynthesis in oil seeds.

Vegetable oils are rich sources of polyunsaturated fatty acids and energy as well as valuable sources of human food, animal feed, and bioenergy. Triacylglycerols, which are comprised of three fatty acids attached to a glycerol backbone, are the main component of vegetable oils. Here, we review the development and application of multiple-level omics in major oilseeds and emphasize the progress in the analysis of the biological roles of key genes underlying seed oil content and quality in major oilseeds. Finally, we discuss future research directions in functional genomics research based on current omics and oil metabolic engineering strategies that aim to enhance seed oil content and quality, and specific fatty acids components according to either human health needs or industrial requirements.

The role of the biochemical composition of soybean seeds in the tolerance to deterioration under natural and artificial aging.

The fast decline in the physiological quality of seeds during storage is a serious problem. It is known that the reduction of seed quality may be related to its biochemical constitution. However, the relationship between the composition and the mechanisms linked to the loss of vigor of soybean seeds during aging has not been elucidated yet. Thus, the aim of this work was to analyze the role of the biochemical composition of soybean seeds in the physiological quality and in the tolerance to deterioration due to natural and artificial aging. Seeds of six soybean genotypes were analyzed initially and after being submitted to natural aging, storage for eight months, and artificial aging, using the temperature of 41 °C and 100 % relative humidity for 96 h. Moisture content, germination and vigor tests were carried out. Also, there were measured the content of oil, total protein, soluble protein, malonaldehyde, and fatty acids palmitic, stearic, oleic, linoleic, and linolenic. It was verified that the physiological quality of soybean seeds decreased with both kinds of aging. However, the deterioration process occurs by distinct mechanisms. The biochemical composition of the seeds is associated with the physiological quality and their storage potential is changed by natural and artificial aging. The tolerance of the seed to deterioration is related to soluble protein and fatty acids content. Oleic fatty acid and soluble protein can be used as indicators of physiological quality in soybean seeds.

Cataloging SCN resistance loci in North American public soybean breeding programs.

Soybean cyst nematode (SCN) is a destructive pathogen of soybeans responsible for annual yield loss exceeding $1.5 billion in the United States. Here, we conducted a series of genome-wide association studies (GWASs) to understand the genetic landscape of SCN resistance in the University of Missouri soybean breeding programs (Missouri panel), as well as germplasm and cultivars within the United States Department of Agriculture (USDA) Uniform Soybean Tests-Northern Region (NUST). For the Missouri panel, we evaluated the resistance of breeding lines to SCN populations HG 2.5.7 (Race 1), HG 1.2.5.7 (Race 2), HG 0 (Race 3), HG 2.5.7 (Race 5), and HG 1.3.6.7 (Race 14) and identified seven quantitative trait nucleotides (QTNs) associated with SCN resistance on chromosomes 2, 8, 11, 14, 17, and 18. Additionally, we evaluated breeding lines in the NUST panel for resistance to SCN populations HG 2.5.7 (Race 1) and HG 0 (Race 3), and we found three SCN resistance-associated QTNs on chromosomes 7 and 18. Through these analyses, we were able to decipher the impact of seven major genetic loci, including three novel loci, on resistance to several SCN populations and identified candidate genes within each locus. Further, we identified favorable allelic combinations for resistance to individual SCN HG types and provided a list of available germplasm for integration of these unique alleles into soybean breeding programs. Overall, this study offers valuable insight into the landscape of SCN resistance loci in U.S. public soybean breeding programs and provides a framework to develop new and improved soybean cultivars with diverse plant genetic modes of SCN resistance.

The Identification of a Quantative Trait Loci-Allele System of Antixenosis against the Common Cutworm (Spodoptera litura Fabricius) at the Seedling Stage in the Chinese Soybean Landrace Population.

Common cutworm (CCW) is an omnivorous insect causing severe yield losses in soybean crops. The seedling-stage mini-tray identification system with the damaged leaf percentage (DLP) as an indicator was used to evaluate antixenosis against CCW in the Chinese soybean landrace population (CSLRP) under three environments. Using the innovative restricted two-stage multi-locus genome-wide association study procedure (RTM-GWAS), 86 DLP QTLs with 243 alleles (2-11/QTL) were identified, including 66 main-effect loci with 203 alleles and 57 QTL-environment interaction loci with 172 alleles. Among the main-effect loci, 12 large-contribution loci (R2 ≥ 1%) explained 25.45% of the phenotypic variation (PV), and 54 small-contribution loci (R2 < 1%) explained 16.55% of the PV. This indicates that the CSLRP can be characterized with a DLP QTL-allele system complex that has not been found before, except for a few individual QTLs without alleles involved. From the DLP QTL-allele matrix, the recombination potentials expressed in the 25th percentile of the DLP of all possible crosses were predicted to be reduced by 41.5% as the maximum improvement and 14.2% as the maximum transgression, indicating great breeding potential in the antixenosis of the CSLRP. From the QTLs, 62 candidate genes were annotated, which were involved in eight biological function categories as a gene network of the DLP. Changing from susceptible to moderate plus resistant varieties in the CSLRP, 26 QTLs had 32 alleles involved, in which 19 genes were annotated from 25 QTL-alleles, including eight increased negative alleles on seven loci and 11 decreased positive alleles on 11 loci, showing the major genetic constitution changes for the antixenosis enhancement at the seedling stage in the CSLRP.

Soybean Yield and Nutrition Grown on the Straw of Grain Sorghum Inoculated with Azospirillum brasilense and Intercropped with BRS Paiaguás Grass.

The adoption of diversified agricultural systems that employ integrated cultural practices appears to be the way to sustainably intensify tropical agriculture. Our objectives were to evaluate the dry matter (DM) accumulation of sorghum inoculated with Azospirillum brasilense, with or without a nitrogen fertilization split, intercropped with palisade grass (Urochloa brizantha cv. BRS Paiaguás), and how these practices influenced the nutrition and development of soybean in succession. The design was a randomized complete block in a 2 × 2 × 3 factorial, consisting of sorghum monoculture cropped or intercropped with palisade grass, sorghum either inoculated or not with A. brasilense, and nitrogen applied at 120 kg ha-1 N only at sowing, only at topdressing, or split-30% at sowing and 70% at topdressing at the beginning of the panicle initiation stage. The residual impacts of these treatments on the following soybean crop were also evaluated. Higher DM yield occurred in sorghum inoculated with A. brasilense, however, this result varied by year. The sorghum-palisade grass intercrop produced a higher amount of straw than sorghum monoculture. The nutrition of soybean was adequate regardless of treatments, but grain yield was higher when the sorghum residue was inoculated. The inoculation of A. brasilense in sorghum intercropped with palisade grass increased yield. The nutrition of soybean was adequate regardless of the treatments, while grain yield was higher on the inoculated sorghum residues. The inoculation of A. brasilense in sorghum intercropped with palisade grass increased DM yield. The intercropping increased the production of biomass for animal grazing and DM for soil coverage. The inoculation of sorghum by A. brasilense and its intercropping with palisade grass contributed to higher soybean yield in succession.

A small heat shock protein GmHSP18.5a improves the male fertility restorability of cytoplasmic male sterility-based restorer line under high temperature stress in soybean.

Small heat shock protein (sHSP) is involved in high temperature (HT) stress response. However, the function of sHSPs in regulating male fertility of soybean under HT stress remains largely unknown. Here, we identified a sHSP gene, GmHSP18.5a, which was responded to HT stress during flowering in cytoplasmic male sterility (CMS)-based restorer line of soybean. Moreover, GmHSFA6b turned out to directly activated the expression of GmHSP18.5a by binding to the heat shock cis-element in its promoter. Overexpression of GmHSP18.5a increased male fertility in transgenic Arabidopsis, soybean CMS-based restorer line and its hybrid F1 with CMS line under HT stress. Reactive oxygen species (ROS) content detection revealed that GmHSP18.5a promoted the ROS scavenging ability of Arabidopsis inflorescence and soybean flower bud under HT stress. Enzyme activity assay and gene expression analysis indicated that GmHS18.5a mainly increased the activity of antioxidant enzymes and the expression level of ROS metabolism-related genes under HT stress. Our results indicated that GmHSP18.5a improved the male fertility restorability of CMS-based restorer line in soybean by regulating ROS metabolic pathway and reducing ROS accumulation. Our findings not only revealed the molecular mechanism of sHSP regulating the male fertility of soybean under HT stress, but also provided a theoretical basis for creating strong restorer line with thermotolerance.

Genome-Wide Characterization of Soybean Hexokinase Genes Reveals a Positive Role of GmHXK15 in Alkali Stress Response.

Hexokinase (HXK) proteins catalyze hexose phosphorylation and are important for the sensing and signaling of sugar. In order to determine the roles played by HXKs in soybean growth and stress responsiveness, seventeen HXK genes (GmHXK1-17) were isolated and analyzed. The phylogenic analysis and subcellular location prediction showed that GmHXKs were clearly classified into type A (GmHXK1-4) and type B (GmHXK5-17). There were similar protein structures and conserved regions in GmHXKs to the HXKs of other plants. An expression analysis of the GmHXK genes in soybean organs or tissues demonstrated that GmHXK3 and GmHXK12, 15, and 16 were the dominant HXKs in all the examined tissues. In addition, salt, osmotic, and alkaline stress treatments dramatically increased the activity and transcripts of GmHXKs. There is the possibility that a type-B isoform (GmHXK15) plays a crucial role in soybean adaptation to alkali, as the expression levels of this isoform correlate well with the HXK enzyme activity. Based on an enzyme assay performed on recombinant plant HXK15 proteins expressed in Escherichia coli, we found that GmHXK15 had functional HXK activities. A further analysis indicated that GmHXK15 specifically targeted the mitochondria, and the overexpression of the GmHXK15 gene could significantly enhance the resistance of transgenic soybean to alkali stress. The present findings will serve as a basis for a further analysis of the function of the GmHXK gene family.