Roots Of Soybean Seedlings Research Articles

GmABCG5, an ATP-binding cassette G transporter gene, is involved in the iron deficiency response in soybean.

Iron deficiency is a major nutritional problem causing iron deficiency chlorosis (IDC) and yield reduction in soybean, one of the most important crops. The ATP-binding cassette G subfamily plays a crucial role in substance transportation in plants. In this study, we cloned the GmABCG5 gene from soybean and verified its role in Fe homeostasis. Analysis showed that GmABCG5 belongs to the ABCG subfamily and is subcellularly localized at the cell membrane. From high to low, GmABCG5 expression was found in the stem, root, and leaf of young soybean seedlings, and the order of expression was flower, pod, seed stem, root, and leaf in mature soybean plants. The GUS assay and qRT-PCR results showed that the GmABCG5 expression was significantly induced by iron deficiency in the leaf. We obtained the GmABCG5 overexpressed and inhibitory expressed soybean hairyroot complexes. Overexpression of GmABCG5 promoted, and inhibition of GmABCG5 retarded the growth of soybean hairy roots, independent of nutrient iron conditions, confirming the growth-promotion function of GmABCG5. Iron deficiency has a negative effect on the growth of soybean complexes, which was more obvious in the GmABCG5 inhibition complexes. The chlorophyll content was increased in the GmABCG5 overexpression complexes and decreased in the GmABCG5 inhibition complexes. Iron deficiency treatment widened the gap in the chlorophyll contents. FCR activity was induced by iron deficiency and showed an extraordinary increase in the GmABCG5 overexpression complexes, accompanied by the greatest Fe accumulation. Antioxidant capacity was enhanced when GmABCG5 was overexpressed and reduced when GmABCG5 was inhibited under iron deficiency. These results showed that the response mechanism to iron deficiency is more actively mobilized in GmABCG5 overexpression seedlings. Our results indicated that GmABCG5 could improve the plant's tolerance to iron deficiency, suggesting that GmABCG5 might have the function of Fe mobilization, redistribution, and/or secretion of Fe substances in plants. The findings provide new insights into the ABCG subfamily genes in the regulation of iron homeostasis in plants.

Нанопрайминг семян сои с применением марганецсодержащего нанокомпозита в арабиногалактановой матрице

The results of studies on the stimulation of soybean seed germination under the influence of nanopriming with a chemically synthesized nanocomposite (NC) based on manganese-containing nanoparticles and a water-soluble polysaccharide arabinogalactan are presented. The study was carried out on the phytopathosystem: soybean seeds Glycine max (L) – phytopathogenic bacterium Pectobacterium carotovorum. Phytopathogenic bacterium P. carotovorum causes the infectious disease soft rot in various plant species from vegetables to trees and shrubs. After nanopriming (treatment Mn(OH)2/AGs NC), seed germination, biometric characteristics (mass and length of the root and hypocotyl) and biochemical parameters of soybean seedlings (content of reactive oxygen species (ROS), activity of antioxidant enzymes, amount of lipid peroxidation products) were analyzed. It was shown that the infection of seeds with P. carotovorum led to a decrease in their germination, 50 % of the seeds did not germinate. In addition, seedlings obtained from infected seeds had reduced all biometric characteristics compared to the control. Infection of seeds with P. carotovorum showed an increase in the amount of ROS in root tissues and caused a significant increase in peroxidase activity in the roots of soybean seedlings. A significant increase in diene conjugates (DC) was noted in the tissues of the roots of the hypocotel in this variant. The nanocomposite of manganese hydroxide and sulfated arabinogalactan (Mn(OH)2/AGs NC, 4,8 % Mn) removed the negative effect of the phytopathogen P. carotovorum. Morphometric characteristics of seed sprouts after nanopriming were characterized by an increase in biomass compared to the control. Thus, after nanopriming with Mn(OH)2/AGs NC, the length and weight of the root in uninfected seeds increased. The most pronounced stimulating effect of nanopriming was expressed in sprouts obtained from infected seeds. The length weight of the hypocotyl and the length of the root in infected seeds significantly increased after nanopriming of infected seeds. The precursor NC – MnSO4×5H2O did not affect the germination and sprouting of seeds both infected with P. carotovorum and free from infection. Nanopriming of infected seeds reduced the formation of ROS in seedling tissues. It was found that after nanopriming, peroxidase activity increased significantly in soybean roots compared to the control. This effect can be explained by the antioxidant effect of Mn NPs. Nanopriming of infected seeds reduced the amount of DC in root tissues to the control level. Thus, the mechanisms of interaction of NC with the studied phytopathosystem are represented by an increase in seed germination under the influence of NC, stimulation of morphometric parameters of seedlings, as well as an effect on the components of the antioxidant system. The obtained results and our previous studies on the antibacterial effect of Mn(OH)2/AGs against phytopathogens Clavibacter sepedonicus demonstrate the great potential of using Mn(OH)2/AGs in practical agriculture, in particular for application in the field of stimulating plant growth and increasing their resistance to phytopathogens.

Нанопрайминг семян сои с применением марганецсодержащего нанокомпозита в арабиногалактановой матрице

The results of studies on the stimulation of soybean seed germination under the influence of nanopriming with a chemically synthesized nanocomposite (NC) based on manganese-containing nanoparticles and a water-soluble polysaccharide arabinogalactan are presented. The study was carried out on the phytopathosystem: soybean seeds Glycine max (L) – phytopathogenic bacterium Pectobacterium carotovorum. Phytopathogenic bacterium P. carotovorum causes the infectious disease soft rot in various plant species from vegetables to trees and shrubs. After nanopriming (treatment Mn(OH)2/AGs NC), seed germination, biometric characteristics (mass and length of the root and hypocotyl) and biochemical parameters of soybean seedlings (content of reactive oxygen species (ROS), activity of antioxidant enzymes, amount of lipid peroxidation products) were analyzed. It was shown that the infection of seeds with P. carotovorum led to a decrease in their germination, 50 % of the seeds did not germinate. In addition, seedlings obtained from infected seeds had reduced all biometric characteristics compared to the control. Infection of seeds with P. carotovorum showed an increase in the amount of ROS in root tissues and caused a significant increase in peroxidase activity in the roots of soybean seedlings. A significant increase in diene conjugates (DC) was noted in the tissues of the roots of the hypocotel in this variant. The nanocomposite of manganese hydroxide and sulfated arabinogalactan (Mn(OH)2/AGs NC, 4,8 % Mn) removed the negative effect of the phytopathogen P. carotovorum. Morphometric characteristics of seed sprouts after nanopriming were characterized by an increase in biomass compared to the control. Thus, after nanopriming with Mn(OH)2/AGs NC, the length and weight of the root in uninfected seeds increased. The most pronounced stimulating effect of nanopriming was expressed in sprouts obtained from infected seeds. The length weight of the hypocotyl and the length of the root in infected seeds significantly increased after nanopriming of infected seeds. The precursor NC – MnSO4×5H2O did not affect the germination and sprouting of seeds both infected with P. carotovorum and free from infection. Nanopriming of infected seeds reduced the formation of ROS in seedling tissues. It was found that after nanopriming, peroxidase activity increased significantly in soybean roots compared to the control. This effect can be explained by the antioxidant effect of Mn NPs. Nanopriming of infected seeds reduced the amount of DC in root tissues to the control level. Thus, the mechanisms of interaction of NC with the studied phytopathosystem are represented by an increase in seed germination under the influence of NC, stimulation of morphometric parameters of seedlings, as well as an effect on the components of the antioxidant system. The obtained results and our previous studies on the antibacterial effect of Mn(OH)2/AGs against phytopathogens Clavibacter sepedonicus demonstrate the great potential of using Mn(OH)2/AGs in practical agriculture, in particular for application in the field of stimulating plant growth and increasing their resistance to phytopathogens.

Effect of Nanopriming with Selenium Nanocomposites on Potato Productivity in a Field Experiment, Soybean Germination and Viability of Pectobacterium carotovorum

In recent decades, the use of nanocomposites (NCs) in crop production has been actively studied. We have previously shown that chemically synthesized selenium nanocomposites (Se NCs) based on natural polymeric matrices of arabinogalactan (Se/AG NCs), carrageenan (Se/CAR NCs), and starch (Se/ST NCs) stimulated the growth and development of potatoes in vitro and had an antibacterial effect against the phytopathogen Clavibacter sepedonicus. It is important to confirm that the results obtained in the laboratory are also reproducible in the field conditions of crop cultivation. In addition, the applications of NCs can be expanded if a wider range of their biological activity is revealed, and the effect on other types of cultivated plants and phytopathogens is shown. In this regard, the purpose of this research was to study the effect of nanopriming with Se NCs on the productivity of potatoes in a field experiment, the germination of soybeans, and the viability of the phytopathogen Pectobacterium carotovorum under in vitro conditions. The study included the use of traditional methods of conducting a field experiment in natural growing conditions, also using microbiological cultures and studying the bacterial profile from the endosphere of potato tubers by the imprint method, germinating Glycine max L. soybean seeds after nanopriming in Petri dishes, followed by the measurement of morphometric and biochemical parameters such as the activity of antioxidant enzymes and content of diene conjugates. Based on the results of field experiments, it was found that the preplant treatment of tubers with Se/AG and Se/CAR NCs stimulated a significant increase in the number of stems in potato plants and tubers per plant, but for Se/AG NC, the increase was observed only in 2020 and 2022, and the stimulating effect of Se/AG and Se/CAR NCs on the weight of tubers was observed only in 2020. In the yield structure, the proportion of marketable seed tubers was increased under the influence of all Se NCs. Endosphere cultures from tubers showed that bacteria were present in only 56% of the tubers in the control, while 78% of the tubers obtained from plants grown from seed tubers treated with Se/AG NC and 100% of the tubers from plants grown from seed tubers treated with Se/ST and Se/CAR NCs contained bacteria. The bacteria were represented by both spore-forming Gram-positive and Gram-negative bacteria of various sizes. The results presented in this article and previously published data showed that the maximum diversity of bacteria was observed after treatment with Se/ST NC. Experiments on potatoes showed that Se/AG NC had the greatest biological effect. In addition, the growth-stimulating effect of these NCs on the biomass of the roots of soybean seedlings was shown. It activated the antioxidant enzymes and reduced the level of diene conjugates (DCs), the amount of which increased significantly after seed biopriming with the phytopathogen Pectobacterium carotovorum. The antibacterial effect of Se/AG NC in relation to the P. carotovorum was observed as a reduction in the growth of the bacterial culture, biofilm formation, and dehydrogenase activity of cells. Thus, it has been shown that Se/AG NC has a stimulating effect on such agriculturally important crops as potatoes and soybeans, as well as an antibacterial effect against Gram-negative and Gram-positive phytopathogenic bacteria.

Overexpression of GmNF-YA14 produced multiple phenotypes in soybean

Soybean is an important oil crop, and more and more soybean gene functions have been reported; however, one soybean gene with multiple functions is rarely seen. The NF-YA subfamily plays a broad regulatory role in plant growth and development, and GmNF-YA14 (Glyma.14G010000) is one of them. We found that the expression level of GmNF-YA14 in the root of soybean seedlings was significantly increased after a one-hour treatment with 200 mM salt. The transgenic soybean was obtained by Agrobacterium-mediated method, and all experiments were carried out using transgenic soybean homozygous lines. Under a 200 mM salt treatment, the leaf chlorophyll content of overexpressed GmNF-YA14 transgenic soybean seedlings was significantly decreased compared to the control. Moreover, the first flowering time of overexpressed GmNF-YA14 transgenic soybean was shortened by more than six days compared to the control, and the growth period structure changed significantly. Overexpressed GmNF-YA14 transgenic soybean plants had two or three branches, whereas control soybean plants had eight or nine branches. Compared to the control, the number of main stem nodes and plant height of overexpressed GmNF-YA14 transgenic soybean plants were significantly reduced. The 100-seed weight of GmNF-YA14 transgenic soybean line OE-8 was significantly higher than that of the control. Transcriptome analysis indicated that the multiple phenotypes of the overexpressed GmNF-YA14 transgenic soybean may be related to the mitogen-activated protein kinase (MAPK) signaling pathway. These results indicated that compared to the control, overexpressed GmNF-YA14 transgenic soybeans had changes in salt stress tolerance, growth period, plant type, and 100-seed weight, and these changes may be related to the MAPK signaling pathway.

Dynamic variation of nutrient absorption, metabolomic and transcriptomic indexes of soybean (Glycine max) seedlings under phosphorus deficiency.

The dynamic trajectory of metabolites and gene expression related to phosphorus absorption and utilization in soybean seedling roots were determined under short- and long-term phosphorus deficiency stress. The metabolome results showed that TCA and GS/GOGAT cycles were enhanced after 2 days of phosphorus deficiency stress; however, they were inhibited after 15 days. GC-TOF-MS showed that phosphorus deficiency increased the accumulation of amino acids significantly after 2 days, whereas organic acids and lipid substances increased significantly after 15 days. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) showed that transcriptional levels of five key genes related to phosphorus activation and phosphorus starvation signal transduction increased continuously with phosphorus deficiency. The expression of GmPHT1 and GmSPX triggered the phosphorus starvation signal pathway and induced the expression of the GmPS and GmPAP genes to enhance the synthesis and secretion of organophosphorus hydrolase and organic acid in soybean roots under phosphorus deficiency. The phospholipid metabolism was enhanced significantly after 15 days of stress and when GmSQD, a crucial enzyme in lipid biosynthesis, was up-regulated. Thus, we propose that future investigations on stress caused by phosphorus deficiency should include more organs obtained at different developmental stages.

Soybean Seedling Root Segmentation Using Improved U-Net Network.

Soybean seedling root morphology is important to genetic breeding. Root segmentation is a key technique for identifying root morphological characteristics. This paper proposed a semantic segmentation model of soybean seedling root images based on an improved U-Net network to address the problems of the over-segmentation phenomenon, unsmooth root edges and root disconnection, which are easily caused by background interference such as water stains and noise, as well as inconspicuous contrast in soybean seedling images. Soybean seedling root images in the hydroponic environment were collected for annotation and augmentation. A double attention mechanism was introduced in the downsampling process, and an Attention Gate mechanism was added in the skip connection part to enhance the weight of the root region and suppress the interference of background and noise. Then, the model prediction process was visually interpreted using feature maps and class activation mapping maps. The remaining background noise was removed by connected component analysis. The experimental results showed that the Accuracy, Precision, Recall, F1-Score and Intersection over Union of the model were 0.9962, 0.9883, 0.9794, 0.9837 and 0.9683, respectively. The processing time of an individual image was 0.153 s. A segmentation experiment on soybean root images was performed in the soil-culturing environment. The results showed that this proposed model could extract more complete detail information and had strong generalization ability. It can achieve accurate root segmentation in soybean seedlings and provide a theoretical basis and technical support for the quantitative evaluation of the root morphological characteristics in soybean seedlings.

Integrating transcriptomic and metabolomic analysis in roots of wild soybean seedlings in response to low-phosphorus stress.

Plants undergo divergent adaptations to form different ecotypes when exposed to different habitats. Ecotypes with ecological adaptation advantages are excellent germplasm resources for crop improvement. his study comprehensively compared the differences in morphology and physiological mechanisms in the roots of two different ecotypes of wild soybean (Glycine soja) seedlings under artificially simulated low-phosphorus (LP) stress. The seedlings of barren-tolerant wild soybean (GS2) suffered less damage than common wild soybean (GS1). GS2 absorbed more phosphorus (P) by increasing root length. In-depth integrated analyses of transcriptomics and metabolomics revealed the formation process of the ecological adaptability of the two different ecotypes wild soybean from the perspective of gene expression and metabolic changes. This study revealed the adaptation process of GS2 from the perspective of the adaptation of structural and molecular metabolism, mainly including: (1) Enhancing the metabolism of phenolic compounds, lignin, and organic acid metabolism could activate unavailable soil P; (2) Up-regulating genes encoding pectinesterase and phospholipase C (PLC) specifically could promote the reuse of structural P; (3) Some factors could reduce the oxidative damage to the membranes caused by LP stress, such as accumulating the metabolites putrescine and ascorbate significantly, up-regulating the genes encoding SQD2 (the key enzyme of sulfolipid substitution of phospholipids) substantially and enhancing the synthesis of secondary antioxidant metabolite anthocyanins and the AsA-GSH cycle; (4) enhancing the uptake of soil P by upregulating inorganic phosphate transporter, acid phosphatase ACP1, and purple acid phosphatase genes; (5) HSFA6b and MYB61 are the key TFs to resist LP stress. In general, GS2 could resist LP stress by activating unavailable soil P, reusing plant structural P, rebuilding membrane lipids, and enhancing the antioxidant membrane protection system. Our study provides a new perspective for the study of divergent adaptation of plants.

The Effect of Neutral Salt and Alkaline Stress with the Same Na+ Concentration on Root Growth of Soybean (Glycine max (L.) Merr.) Seedlings

Salt stress is a common abiotic stress that negatively affects crop growth and yield. However, there have been significant differences found on the effect degree and management mechanism in plants under neutral salt stress and alkaline stress. In this study, two soybean cultivars, Heihe 49 (HH49, saline-alkali stress tolerant) and Henong 95 (HN95, saline-alkali stress sensitive), were hydroponically cultured and treated with salt solutions of 25, 50, and 75 mM Na+ in the form of NaCl, Na2SO4, NaHCO3, and Na2CO3. Plants treated with alkaline stress (NaHCO3 and Na2CO3) showed a greater decrease in root growth and root activity of both soybean cultivar seedlings than that under neutral salt stresses (NaCl and Na2SO4) with 25–75 mM Na+ concentration. Alkaline stress (25–50 mM Na+ content) activated a higher ability of antioxidant defense (by enhancing the activists of superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX)) and increased the content of soluble sugars to a higher level than that under neutral salt stresses. However, 75 mM Na+ content salt treatments reduced antioxidant enzyme activities and osmotic regulating substance content. Furthermore, alkaline salt and neutral salt stress was able to induce DNA damage and cell cycle arrest in HH49 and HN95 seedling roots. Treatment with Na2CO3 induced the least random amplification polymorphic DNA (RAPD) polymorphism in soybean seedling roots among all salt treatments, which could have been related to the early cell cycle arrest.

Effect of interaction between Meloidogyne incognita and Cowpea mild mottle virus on soybean

The study investigated the effects of the interaction between Meloidogyne incognita and Cowpea mild mottle virus on soybean cultivars. Two weeks after planting, treatments were applied to the plants in both the screenhouse and field trials as listed; single inoculation of 5,000 eggs of M. incognita on roots of soybean seedlings, single inoculation of leaves of soybean seedlings with CPMMV sap, mixed inoculation 5,000 eggs of M. incognita on roots of soybean seedlings 2 days before inoculating leaves with CPMMV sap, mixed inoculation of leaves of soybean seedlings with crude CPMMV sap 2 days before inoculating plant roots with 5,000 eggs of M. incognita, simultaneous inoculation of leaves of soybean seedlings with crude CPMMV sap and plant roots with 5,000 eggs of M. incognita, and uninoculated plants (control). Data were collected on plant height, number of leaves showing symptoms, grain weight and nematode populations. The results showed that combined inoculations of CPMMV and M. incognita reduced the population density of the nematode and increased the growth and grain yields of M. incognita infected soybean cultivars. It also revealed that plants inoculated with the nematode at 2 days before the virus was inoculated significantly reduced growth and yields of soybean and increased nematode population densities compared to single infections and other combined infections.

Molecular Characterization and Drought Resistance of GmNAC3 Transcription Factor in Glycine max (L.) Merr.

Soybean transcription factor GmNAC plays important roles in plant resistance to environmental stresses. In this study, GmNAC3 was cloned in the drought tolerant soybean variety “Jiyu47”, with the molecular properties of GmNAC3 characterized to establish its candidacy as a NAC transcription factor. The yeast self-activation experiments revealed the transcriptional activation activity of GmNAC3, which was localized in the nucleus by the subcellular localization analysis. The highest expression of GmNAC3 was detected in roots in the podding stage of soybean, and in roots of soybean seedlings treated with 20% PEG6000 for 12 h, which was 16 times higher compared with the control. In the transgenic soybean hairy roots obtained by the Agrobacterium-mediated method treated with 20% PEG6000 for 12 h, the activities of superoxide dismutase, peroxidase, and catalase and the content of proline were increased, the malondialdehyde content was decreased, and the expressions of stress resistance-related genes (i.e., APX2, LEA14, 6PGDH, and P5CS) were up-regulated. These expression patterns were confirmed by transgenic Arabidopsis thaliana with the overexpression of GmNAC3. This study provided strong scientific evidence to support further investigation of the regulatory function of GmNAC3 in plant drought resistance and the molecular mechanisms regulating the plant response to environmental stresses.

Detection and Imaging of the Plant Pathogen Response By Near Infrared Fluorescent Polyphenol Sensors

Plants use secondary metabolites such as polyphenols for chemical defense against pathogens and herbivores. Despite their importance in plant pathogen interactions and tolerance to diseases, it remains challenging to detect polyphenols in complex plant tissues. Here, we create molecular sensors for plant polyphenol imaging that are based on near-infrared (NIR) fluorescent single wall carbon nanotubes (SWCNTs). We identified polyethylene glycol-phospholipids that render (6,5)-SWCNTs sensitive (Kd = 90 nM) to plant polyphenols (tannins, flavonoids, ...), which red-shift (up to 20 nm) and quench their emission (~1000 nm). These sensors report changes in total polyphenol level after herbivore or pathogen challenge in crop plant systems (Soybean Glycine max) and leaf tissue extracts (Tococa spp). We furthermore demonstrate remote chemical imaging of pathogen-induced polyphenol release from roots of soybean seedlings over the time course of 24h. Additional use of chirality-pure polyphenol sensors gives further access to ratiometric sensing and imaging applications. Overall, this approach allows in situ visualization and understanding of the chemical plant defense in real time and paves the way for plant phenotyping for optimized polyphenol secretion.

Exogenous melatonin enhances soybean (Glycine max (L.) Merr.) seedling tolerance to saline-alkali stress by regulating antioxidant response and DNA damage repair.

Saline-alkali (SA) stress induces excessive reactive oxygen species (ROS) accumulation in plant cells, resulting in oxidative damages of membranes, lipids, proteins, and nucleic acids. Melatonin has antioxidant protection effects in living organisms and thus has received a lot of attention. This study aimed to investigate the effect and regulating mechanism of melatonin treatment on soybean tolerance to SA stress. In this study, cultivars Heihe 49 (HH49, SA-tolerant) and Henong 95 (HN95, SA-sensitive) were pot-cultured in SA soil, then treated with MT (0-300 μM) at V1 stage. SA stress induced ROS accumulation and DNA damage in the seedling roots of both cultivars, causing G1/S arrest in HN95 and G2/M arrest in HH49. Melatonin treatment enhanced the activity of antioxidant enzymes in soybean seedling roots and reduced ROS accumulation. Additionally, melatonin treatment upregulated DNA damage repair genes, thus enhancing the reduction of DNA oxidative damage under SA stress. The effects of melatonin treatment were manifested as decreased RAPD polymorphism, 8-hydroxy-2'-deoxyguanine (8-OH-dG) level, and relative density of apurinic sites (AP-sites). Meanwhile, melatonin treatment partially alleviated the SA-induced G1/S arrest in HN95 and G2/M arrest in HH49, thus enhancing soybean seedling tolerance to SA stress.

Oxidative RNA Modifications as an Early Response of Soybean (Glycine max L.) Exposed to Copper and Lead.

Plant exposure to metals is associated with the accumulation of reactive oxygen species, which mediate the oxidation of various molecules including lipids, proteins, and nucleic acids. The aim of the present study is the evaluation of the impact of short-term Cu and Pb treatment on oxidative events in the roots of soybean seedlings, with special emphasis on RNA oxidation. The results show that an increase in total RNA oxidative modification, 8-hydroxyguanosine (8-OHG), constitutes a very early response to both applied metals, observed already within the first hour of treatment. Exposure to Cu and Pb resulted also in the increase in superoxide anion and hydrogen peroxide levels and intensified lipid peroxidation. However, these responses were most prominent after longer treatment times. On the other hand, no changes were observed in the level of protein carbonylation. It can be concluded that 8-OHG enrichment in total RNA constitutes one of the earliest reactions to metals, which precedes the symptoms of oxidative stress.

Effects of Phosphorus on Growth and Development of Soybean Seedlings

Soybean seedlings were treated with different phosphorus (P) concentrations for 20 days to investigate their growth and development. The root growth and development of soybean seedlings was the best when the concentration of phosphorus was 250 μmol/L. After 20 days of cultivation at this concentration, the roots of soybean seedlings were developed, indicating that the main root length, lateral root length, and the number of lateral root was the best among all treatments, and the number of lateral roots was quite a few. In addition, when the concentration of P was at 250 μmol/L, it had a better promotion effect on the plant height of soybean seedlings, and could significantly enhance the development of soybean seedlings. Moreover, the growth of soybean seedlings would be inhibited at the condition of phosphorus deficiency or excessive phosphorus. In this experiment, the growth indexes of soybean seedlings were compared between four treatments of phosphorus concentration, so as to make a basic study on the physiological effect of soybean on phosphorus in early stage.

Ростостимулирующая активность медьсодержащих нанокомпозитов в природных полимерных матрицах

The biological activity of two chemically synthesized nanocomposites (NC) of copper(I) oxide (Cu2О) based on natural polymer matrices of arabinogalactan (AG) and starch (ST) was studied in order to develop a new growth stimulator for plants. The results of experiments on studying the effect of NC on the growth rates (length and weight of stems, biomass of roots) of soybean seedlings and the content of diene conjugates (DC) in the tissues of their stems, as well as on the growth of stems and the number of leaves, the biomass of the aerial parts of plants and roots of the potato variety “Lugovskoy” in vitro, infected with the causative agent of ring rot – the bacterium Clavibacter sepedonicus and controls, and the content of DC in the tissues of their leaves and roots. The results of the study of the growth-stimulating effect on plants of Cu2O/AG and Cu2O/ST showed that only NC Cu2O/AG has this effect. Microscopy of potato root tissues using fluorescent dyes showed that when processing potatoes with NC Cu2О /AG, its roots do not die, the cells remain viable. The effect of the nanocomposite copper oxide-starch Cu2O/ST on soybean seedlings was expressed in a decrease in the growth and weight of the stems, a neutral effect on the length and weight of the roots, and an increase in the content of DC in their tissues. The same kind of effect was also registered on microclonal potato plants. On the contrary, the nanocomposite of copper oxide – arabinogalactan Cu2O/AG stimulated an increase in the length and weight of the stems of soybean seedlings, as well as the biomass of roots and significantly reduced the level of DC in their tissues. A negative effect on the growth and development of potatoes, as well as the status of the redox system of potatoes, both infected with the Cms pathogen and free from infection, was not established: the level of DC in its tissues did not increase. The experiments performed indicate the prospects of using the nanocomposite copper oxide – arabinogalactan Cu2O/AG of arabinogalactan as a means for combating bacterial pathogens of agricultural crops.

Detection and Imaging of the Plant Pathogen Response by Near-Infrared Fluorescent Polyphenol Sensors.

Plants use secondary metabolites such as polyphenols for chemical defense against pathogens and herbivores. Despite their importance in plant pathogen interactions and tolerance to diseases, it remains challenging to detect polyphenols in complex plant tissues. Here, we create molecular sensors for plant polyphenol imaging that are based on near‐infrared (NIR) fluorescent single‐wall carbon nanotubes (SWCNTs). We identified polyethylene glycol–phospholipids that render (6,5)‐SWCNTs sensitive (Kd=90 nM) to plant polyphenols (tannins, flavonoids, …), which red‐shift (up to 20 nm) and quench their emission (ca. 1000 nm). These sensors report changes in total polyphenol level after herbivore or pathogen challenge in crop plant systems (Soybean Glycine max) and leaf tissue extracts (Tococa spp.). We furthermore demonstrate remote chemical imaging of pathogen‐induced polyphenol release from roots of soybean seedlings over the time course of 24 h. This approach allows in situ visualization and understanding of the chemical plant defense in real time and paves the way for plant phenotyping for optimized polyphenol secretion.

Allelopathic Impact of Cover Crop Species on Soybean and Goosegrass Seedling Germination and Early Growth

Cover crops can provide a variety of benefits to an agricultural system: weed suppression, soil quality improvement, and soil water infiltration. Although there is ample research documenting weed suppression from cover crops, the mechanics of the suppression are not implicitly understood. Along with the aforementioned positive attributes, negative allelopathic effects on row crops planted into cover crop systems have been documented. The objective of this study was to evaluate the allelopathic potential of certain cover crop species on soybean (Glycine max L.) and goosegrass (Eleusine indica L.) germination and early seedling growth under controlled environments in petri dish and pot experiments. Leachates from above-ground biomass of five cover crop species, wheat (Triticum aestivum L.), cereal rye (Secale cereale), hairy vetch (Vicia villosa), crimson clover (Trifolium incarnatum L.), and canola (Brassica napus L.), from two locations (East and Middle Tennessee) were extracted and applied at 0 (water) and 50 v/v. In experiment I, both soybean and goosegrass seeds were examined, and, in experiment II, only soybean seeds were examined under the application of cover crop leachates. Most cover crop leachates from both locations significantly reduced the soybean seedling root length (p < 0.01). Overall, the application of canola extract (East Tennessee) suppressed soybean seed germination the most (28%) compared to deionized water. For goosegrass, the wheat cover crop leachate significantly reduced seedling root length (p < 0.01). In experiment II, the soybean root nodulation was significantly increased with the wheat extract treatment compared to deionized water. While the results indicate that the location and environment may change cover crop species allelopathic potential, the wheat cover crop leachate had the most potent allelopathic impact on goosegrass germination and growth; however, had the lowest observed adverse effect on our tested row crop, soybean.

Physiological and transcriptomic response of soybean seedling roots to variable nitrate levels

AbstractNitrate is the main nitrogen source for plant growth and development. Increasing evidence indicates that nitrate plays an important role in root growth and development. However, the effects of different concentrations of nitrate on the physiological and transcriptional response of soybean [Glycine max (L.) Merr.] root development at the seedling stage are not well understood. In this study, we found that both high and low concentrations of nitrate inhibited the growth and development of the soybean root system compared with optimal nitrate supply at the seedling stage. Using transcriptome sequencing technology, we identified 1,654, 1,283, and 2,083 significantly differentially expressed genes in soybean root grown under the low nitrate concentration, optimal nitrate concentration, and high nitrate concentration conditions, respectively. These genes were enriched in the Gene Ontology terms of metabolic process, catalytic activity, and membrane. The genes enriched in the pentose and glucuronate interconversions and glutathione metabolism pathways may play important roles during soybean root response to different concentrations of nitrate. In addition, the expression of 18 nitrate transporter genes changed significantly under different nitrate concentrations. Among them, the expression of two GmNPF6.3 genes was upregulated under the NL condition but downregulated under the NH condition, whereas six GmNPF7.3 genes exhibited opposite expression patterns. Taken together, our physiological data can enable a better understanding of the soybean root response under different nitrate concentrations, and the transcriptome data provide a list of candidate genes for further investigation of the mechanisms of root response under different nitrate concentrations.

SOYBEANS SEED PRODUCTIVITY UNDER THE ACTION OF GROWTH STIMULATING DRUGS

Biostimulants are the kind of "doping", due to which crops gain great vitality for crop formation. Growth stimulating drugs make a positive effect on the soil microflora, they are rapidly transformed by soil microorganisms, plant cells. The aim of the work was to substantiate scientifically the use of stimulating growth regulators –Epin-extra, Agorostimulin, Rival, and Kornevin, as the elements of soybean growing technology;to identify their effect on biological characteristics and seed productivity of the crop. The research was conducted on soybean variety Millennium. Pre-sowing experimental treatments of seeds were carried out with aqueous solutions of Epin-extra (0,025 g l), Agorostimulin (1 ml/l), Rival (1 ml/l) and Kornevin (0,5 g/l), and control – with water. During the study laboratory germination and energy of germination of seeds, and also morphometric indicators of seedlings and roots were defined. It was found that the pre-sowing treatment of soybean seeds of Millennium variety with stimulant drugs – Epin-extra (0,025 g/l), Agorostimulin (1 ml/l), Rival (1 ml/l) and Cornevin (0,5 g/l) increased seed productivity. In all variants of the experiment, both germination energy and seed germination were increased. It was found that the most effective drugs for the increase of germination energy and seed germination of Millennium soybeans are Epin-extra (0,025 g/l) and Agorostimulin (1 ml/l). Under the action of plant growth stimulators, morphometric changes occurred in soybean seedlings. The drugs affected the length of the hypocotyls in seedlings of soybean culture. Under the use of Epin-extra (0,025 g/l) the length of hypocotyls increased by 18 %, under the action of Agorostimulin (1 ml/l) – by 32 %, under Cornevin (0,5 g/l) treatment - by 41 % and after the use of the drug Rival (1 ml/l) – by 85 %. Stimulators helped to lengthen the main root of soybean seedlings. The largest indicator of the length of the main root was found under the treatment of such drugs Riaval and Agorostimulin. It was found that all studied drugs contributed to the regrowth of lateral roots in soybean seedlings, but the best effect was observed under the usage of the drug Cornevin (0,5 g/l). The significant increase in the dry weight of Millennium soybean seedlings was revealed with the use of stimulating plant growth regulators. The increase of the dry weight of soybean seedlings was detected under the pre-sowing treatment of seeds with Cornevin (by 36 %), Agrostimulin (by 50 %), and Rival (by 88 %) in comparison to the control. Pre-sowing treatment of soybean seeds leads to the increase of dry weight of roots. The best effect on the increase of dry weight of roots was found under the use of drugs Cornevin and Agrostimulin. The use of Epin-extra and Rival also led to a positive result, but not as significant as after the use of two previous drugs that were given above.