Nodule Mass Research Articles

Abstract 1147: A novel anti-Galectin-3 antibody therapeutic for the treatment of triple negative breast cancer

Abstract About 43,600 women in the U.S. are expected to die in 2021 from breast cancer. Triple negative breast cancer (TNBC), which accounts for approximately 15% of all breast cancers, is diagnosed by exclusion of expression and/or amplification of three biomarkers (estrogen receptor [ER], progesterone receptor [PR], and human epidermal growth factor receptor 2 [HER2]).Characterized by a high risk of relapse (one half of patients with early stages experience recurrence), short overall survival and progression-free survival (life expectancy of few months after failure of first-line chemotherapy), TNBC represents a high unmet medical need. Galectin-3 plays multiple roles in tumor initiation and development via a variety of cellular processes, spanning from angiogenesis to tumor migration. Galectin-3 (Gal3) expression is induced in TNBC patients and highly correlates with poor survival, as shown by our and others’ bioinformatics analysis from public database. We recently discovered and patented a series of antibodies with high specificity and affinity for Gal3, one of which is currently tested in human volunteers. This clinical candidate has shown superior pharmacokinetic properties and clean toxicity profile in GLP studies on non-human primates. Here, we show that anti-Gal3 inhibit both anchorage dependent and independent growth of TNBC cells, as well as Gal3-induced escape from NK cell killing. Also, anti-Gal3 proved to be efficacious in in vivo studies, where TNBC cells were implanted in mammary fat pads of mice and tumor progression, measured as growth of primary mass and presence of metastatic nodules in the lungs, was followed during the two months of treatment. The results presented herein support the conclusion that our therapeutic modality could offer an alternative promising treatment of TNBC. Citation Format: Li Zhang, Heng Wu, Karyssa Palopo, Jie Hu, Marvin Cadiente, Anh Nguyen, Teodelinda Mirabella, Dongxu Sun. A novel anti-Galectin-3 antibody therapeutic for the treatment of triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1147.

NITROGEN FERTILIZATION IN SOYBEAN UNDER LOW LATITUDE AND LOW NATURAL SOIL FERTILITY

In soybean, some studies have shown yield increase when nitrogen is provided through symbiotic fixation along with nitrogen fertilization. Thus, this study aimed to evaluate the effect of nitrogen fertilization on soybean cultivated at a low natural fertility area. Two experiments (field and pot) were conducted. A randomized block design was adopted, with 24 treatments and 3 replications. The treatments were arranged in a 2x12 factorial scheme, represented by two cultivars (TMG 1288RRTM and CD 251RRTM) and 12 combinations of nitrogen supply (CNS). The CNS used were: without inoculant and nitrogen; only inoculant; 20; 40 and 60 kg ha-1 of N + inoculant; 50; 100; 150; 200; 250; 300 and 350 kg ha-1 of N. The doses of N were divided into three applications: 20% applied at planting, 40% at early flowering and 40% at grain-filling. The nitrogen fertilization associated with seed inoculation did not result in significant gains for crop yield. The mineral nitrogen supply affected negatively the number and mass of nodules, and positively the root mass.

Improving yield and health of legume crops via co-inoculation with rhizobia and Trichoderma: A global meta-analysis

Trichoderma is a genus of fungi used for biocontrol and plant growth promotion; however, effects of co-inoculation with rhizobia in legumes still require detailed analysis. This study conducted a global meta-analysis of 59 published studies (1992–2021) on co-inoculation of legumes with rhizobia and Trichoderma spp. to assess factors affecting the efficiency of plant growth compared to inoculation exclusively with rhizobia. Co-inoculation favored plants by reducing disease incidence (−44%) and increasing root mass (+17%), nodule number (+32%), nodule mass (+37%), nodule nitrogenase activity (+35%), shoot nitrogen content (+8%), and grain yield (+14%). Co-inoculation of legumes can decrease root diseases caused by Fusarium spp., Rhizoctonia spp., Macrophomina phaseolina, Pythium debaryanum and Sclerotium rolfsii and also has potential as a plant growth promoter regardless of plant health. Positive effects of co-inoculation on grain yield and root mass were observed under the majority of the factors evaluated (e.g., legume species, microorganisms, co-inoculation methods, experimental conditions, plant health status, and edaphic factors). Co-inoculation with rhizobia and Trichoderma spp. may contribute to sustainable intensification of legume production systems due to multiple plant benefits under a wide range of conditions.

ResidualBradyrhizobiuminoculation effects on soybean performance and selected soil health parameters

AbstractThe persistence of inoculants from year to year in soybean [Glycine max (L.) Merr.] cultivation and the residual benefits in soybean production are pertinent to adopting such practices in sub‐Saharan Africa countries such as Ghana. A study was conducted to determine the residual effect of commercial rhizobium inoculants on soybean and selected soil health parameters after three cropping seasons. The experimental design was a split‐plot. The main plot consisted of three soybean cultivars (Jenguma, Afayak, and Songda), and the subplot comprised of three peat‐based commercial bradyrhizobium inoculants (Biofix, Legumefix, and NoduMax) and an uninoculated control. Assessments were made on nodulation, shoot dry matter (DM), grain yield, grain total N uptake, permanganate‐oxidizable carbon (POXC), soil pH, and potentially mineralizable C. Among the soybean cultivars, Afayak produced greater nodule mass on the lateral root and the whole root system compared with the other cultivars. Jenguma and Afayak yielded greater shoot DM relative to Songda. Regarding the inoculants, Biofix increased nodule mass on the lateral root and the whole root system compared with the control. Biofix and NoduMax produced superior grain yield relative to the control. Biofix also produced greater grain yield than Legumefix. A superior pod harvest index and an improved grain total N uptake were produced by Biofix compared with Legumefix and the control. Commercial inoculants enhanced POXC availability at harvest, whereas potentially mineralizable C declined with inoculation treatments. Commercial inoculants (Biofix and NoduMax) enhanced nodulation, grain yield, and selected soil health indicators 3 yr after inoculation.

Combination of Azospirillum and Bradyrhizobium on Inoculant Formulation Improve Nitrogen Biological Fixation in Soybean

Co-inoculation in soybean with Azospirillum brasilense and Bradyrhizobium spp. is a consolidated practice to ensure nitrogen supply and maximize productivity and sustainability. This study aimed to evaluate the agronomic efficiency of the co-inoculation in soybean, via seed or in-furrow, of doses of the mixed inoculant containing Bradyrhizobium spp. and A. brasilense in the same formulation. The experiments were conducted under field conditions in four different edaphoclimatic regions to compare seven treatments: Control without nitrogen (N) and inoculant (T1), 200 kg ha-1 of mineral N fertilizer (T2), 100 mL of standard liquid inoculant of Bradyrhizobium spp. (T3) in 50 kg-1 seeds, 100 mL (T4) or 200 mL (T5) of the mixed liquid inoculant in 50 kg-1 seeds, 200 mL (T6) or 300 mL (T7) ha-1 of the mixed inoculant applied in-furrow. Nodulation characteristics (number and mass of nodules) and carbon and N metabolism (dry mass, N content, and N accumulation in the aerial part) were evaluated at the phenological stage R2 (full flowering—there is an open flower at one of the two uppermost nodes). At maturity (R8—full maturity—95% of the pods have reached their full mature color), yield, the mass of 1,000 grains, N content in the grains, and grain N export were measured. The data were submitted to analysis of variance using the F test and comparison of means was performed using the Duncan test (5%). Under field conditions, the mixed inoculant at doses of 200 mL 50 kg-1 seed or 300 mL ha-1 applied in-furrow were equivalent or superior to the standard inoculant for the total number of nodules, N content in the grains, grain N export, productivity, and mass of 1,000 grains. The use of the mixed inoculant containing Bradyrhizobium spp. and A. brasilense in the same formulation meets the demand of grain N export and resulted in increases of 28%, 18% and 7.4% in soybean productivity compared with control without nitrogen, mineral N fertilizer and standard liquid inoculant of Bradyrhizobium spp. respectively.

Influence of common bean genotypes and rhizobia interaction for nodulation and nitrogen fixation

Bacteria from the rhizobia group are able to associate symbiotically with bean crop, forming nodules in the root, in which the biological nitrogen-fixing process occurs. However, the efficiency of this process has been low and it can be attributed to genetic and environmental factors. Thus, the objective of this study was to evaluate the capacity of nodulation of local varieties and commercial common bean cultivars inoculated with a Rhizobium tropici strain used in commercial inoculants and rhizobia isolates from common bean root nodules. The experiment was carried out in a factorial scheme (2x4), in a randomized block design with four replicates. It was tested two local varieties and two commercial cultivars, inoculated with the reference Rhizobium tropici strain CIAT899 and the RBZ14 strain isolated from common bean nodules grown in soils of Southern Brazil, in adapted Leonard-type pots. The CIAT899 strain promoted either higher mass of viable nodules and higher nitrogen accumulation in the aerial part. The black group local variety showed better response than the cultivar TAA Dama for nodule viability, suggesting more efficiency for nodulation. The interaction between genotypes (local varieties and commercial cultivars) and bacteria showed the specificity of the complex symbiotic relationship of biological nitrogen fixation in common bean, requiring further studies of these interactions.

EFFECTIVENESS OF SOYBEAN INOCULATION WITH NODULE BACTERIA AND MYCORRHIZAL FUNGI IN THE CONDITIONS OF THE RIGHT BANK FOREST STEPPE OF UKRAINE

The relevance of this study is determined by a complex of factors that shape soybean grain productivity – the effectiveness of symbiotic systems formed with nodule bacteria and mycorrhizal fungi, the activity of growth processes and the formation of vegetative organs by soybean plants, as well as their adaptive plasticity under the influence of various external factors. The purpose of this study was to investigate the morphobiometric characteristics of soybean plants, the productivity of the crop after pre-sowing treatment with biological preparations Rhizoline, Mycofriend, and Rhizosave. This paper presents the results of research on the use of soybean seed treatment with biological preparations to improve the growth and development of soybean plants and increase crop productivity. Field, laboratory, mathematical-statistical, and calculation methods were employed for this study. It was found that seed inoculation positively affects the leaf surface area in the budding phase, it increased from 5,313 cm2 in the control to 6,426 cm2 with the Rhizoline + Rhizosave + Mycofriend option, and in the phase of pod formation, respectively, from 8,704 cm2 to 1,113 cm2 . The joint use of Rhizoline + Mycofriend + Rhizosave preparations most contributed to the increase in the mass of the root with nodules (+0.95 g), the number of nodules on the plant (+32 pcs), and the mass of nodules from the plant (+0.3 g). It was found that a comparable situation occurred during the phase of bean formation. The regularity of yield growth during the years under study showed that the average increase in yield varied from 0.41 t/ha with Rhizoline + Rhizosave inoculation to 0.6 t/ha with the combined use of Rhizoline + Rhizosave and the mycorrhizal preparation Mycofriend. It was substantiated that under appropriate conditions, the intensity of symbiotic nitrogen fixation increases thanks to nodule bacteria, as well as the absorption of water and nutrients by the root system of plants due to the activity of mycorrhizal fungi, the entry of amino acids, phytohormones, and vitamins into the plant, which positively affects the growth and development of soybean plants. The materials of this paper are of practical value for farmers in the development of new plant nutrition strategies involving biological preparations in the cultivation technology

The use of the nodule bacteria as a remedy for expanding adaptive possibilities of soybean under drought conditions

Symbiotic systems created by soybean variety Almaz (Glycine max (L.) Merr.) and strains of nodule bacteria Bradyrhizobium japonicum 646, РС09, В157 with were investigated under different water supply are investigated (30 and 60 % field capacity, FC). It was shown that drought inhibited the process of nodulation, depending on the functional and adaptive capacity of each of the microsymbionts. The number and mass of root nodules on plants decreased compared to control plants under insufficient watering. Insufficient watering (30 % FC) negatively impacted the functioning of symbiotic systems Glycine max (L.) Merr.—Bradyrhizobium japonicum depending on the drought duration. Strains of Bradyrhizobium japonicum PC09 and B157 formed more drought-tolerant symbiotic systems. They had higher nitrogen fixing activity under reduced moisture supply (30 % FC) and during the recovery period compared to the Bradyrhizobium japonicum 646 strain. It was shown that with increasing drought duration (from the 3rd to the 10th day) the difference in physiological and symbiotic parameters between treated and control plants increased, but with the resumption of watering they partially leveled depending on the inoculant strain.

Disseminated Mycobacterium tuberculosis: An Unusual Presentation with Associated Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare, potentially fatal, and systemic hyperinflammatory syndrome with exacerbated and uncontrolled activation of histiocytes and lymphocytes against mature cells. Secondary HLH can occur in association with a myriad of underlying infections or malignancies. Our patient is a 38-year-old male prisoner with poorly controlled diabetes and no known other medical conditions. He was referred to our emergency department with three-week history of worsening malaise, weight loss, fever, bruising, and shortness of breath; imaging showed pneumomediastinum, lung nodule, and adrenal mass. Biopsy of the lung nodule revealed acid-fast bacilli. Furthermore, bone marrow biopsy showed foci of necrosis with associated acid-fast bacilli and hemophagocytosis highlighted by CD163 stain; consequently, secondary HLH was suggested. Hence, lab results were reviewed and found to satisfy five of the eight secondary HLH criteria. Moreover, ferritin was >10,000 ng/ml, which has been suggested to be highly suspicious for HLH. The patient was started on anti-MAC therapy. Unfortunately, the patient's status declined rapidly; he developed multi-organ failure and succumbed to disease. Later, his culture confirmed Mycobacterium tuberculosis. In conclusion, we presented a rare and challenging case of secondary HLH associated with disseminated Mycobacterium tuberculosis. A high index of suspicion is required for early diagnosis and treatment, and pathologists should be aware of Mycobacterium tuberculosis' association with secondary HLH.

Inga uruguensis response to lead: effects on growth and nitrogenous compounds

Abstract Lead (Pb) is a heavy metal considered one of the major soil pollutants. Phytoremediation is a sustainable and economically viable biological method for reducing Pb content in the environment. Inga uruguensis is a tree legume species that has characteristics favorable to phytoremediation, such as rapid growth and high biomass production. The objective of this work was an initial evaluation of tolerance and phytoremediation potential of I. uruguensis to Pb. The experiment was carried out in a greenhouse. In addition to the control, soil contamination was carried out with the following Pb doses: 100, 200, 300, 400, and 500 mg.dm³, with 5 repetitions in each treatment, totaling 30 vases. We assessed growth, number and mass of nodules, chlorophyll content, ureids, amino acid, protein and soluble carbohydrates in leaves, roots and nodules, tolerance index, dry matter, and tissues Pb content of I. uruguensis. The data were analyzed by the Tukey test using R and SISVAR software. There was no negative effect of Pb in soil on I. uruguensis growth, the symbiotic relationship with rhizobia was kept, even at high Pb content and the tolerance index was not lower than 0.69. Inga uruguensis has initial tolerance and potential to be used as phytoremediation in soils contaminated by Pb.

ВПЛИВ ГЕРБІЦИДУ І БІОЛОГІЧНИХ ПРЕПАРАТІВ НА БОБОВО-РИЗОБІАЛЬНИЙ АПАРАТ "CICER ARIETINUM L. – MESORHIZOBIUM CICERI" ТА ЯКІСТЬ ВРОЖАЮ НУТУ

The results of research on the effect of different rates of Panda herbicide, Stimpo growth regulator and Rizobofit microbial preparation on leaf surface area formation and chickpea cultivar Pamyat’ yields are presented. As a result of the conducted research, the most effective combination of preparations, which provides a significant increase of number and mass of nitrogen-fixing nodules and as a result grain productivity of chickpea crops, was established.Purpose. To study the effect of different rates of Panda herbicide applied separately or in the background of plant treatment with biologic preparations – plant growth regulator Stimpo and microbial preparation Rizobofit – on the formation of legume-rhizobial apparatus of chickpea and yield of chickpea variety Pamyat.

Soybean (Glycine max (L.) Merr.) Growth, Yield, and Nodulation in the Early Transition Period from Conventional Tillage to Conservation and No-Tillage Systems

Soybean (Glycine max (L.) Merr.) is the most important protein crop globally, with its cultivation area in Europe on the increase. To investigate how alternative tillage systems affect soybean growth, yield performance, and nitrogen fixation capacity in the early conversion period from conventional tillage to conservation and no-tillage practices, a field study was conducted in 2020 under the humid central European climatic conditions of Slovenia. A complete randomized block design with four repetitions was used for the three different tillage systems (conventional, conservation, and no-tillage). The results show that the majority of the studied soybean growth parameters (e.g., plant density, nodes per plant, and shoot and root dry matter) and the yield components (e.g., pods per plant, and 100-seed mass) were greatest for the reference conventional tillage system. The conventional system also showed significantly greater dry nodule mass (p < 0.01) and proportion of large-sized nodules (>4 mm) on both the tap root (p < 0.05) and the lateral roots (p < 0.001). A positive linear correlation between nitrogen content and nodule production in the roots also suggested increased nitrogen fixation for the conventional system. The less intensive conservation and no-tillage systems resulted in significantly greater soil compaction, which negatively affected early plant establishment and resulted in significantly decreased plant densities. Despite the large differences in plant stands and individual plant performances, no significant differences were seen for dry seed yields between these tillage systems. Dry seed yields for the conventional and conservation systems were 4.54 and 4.48 t ha−1, respectively, with only minor (non-significant) yield reduction for the no-tillage system, at 4.0 t ha−1. These data show that soybean cultivation in the early transition period to less intensive tillage systems have no major yield losses under these less suitable agro-climatic conditions if correct crop and weed management measures are implemented.

A new function of white-rot fungi Ceriporia lacerata HG2011: improvement of biological nitrogen fixation of broad bean (Vicia faba)

The inoculation of plant growth-promoting microbes with multifarious functions is a simple, economic, and effective way to improve nodulation and biological nitrogen fixation (BNF) of legumes. Broad bean (Vicia faba) is commonly grown in the winter in tropics and subtropics for increasing soil N and farmers’ income. The new functions of Ceriporia lacerata HG2011, a white-rot fungus, in nodulation and BNF (measured by 15N natural abundance) were studied with the broad bean in liquid culture, soil incubation, and greenhouse pot experiments. The results showed that this fungus released IAA, GA, and Fe-binding ligands into culture solutions, increased lateral roots and root surfaces, and mobilized phosphorus and iron into bioavailable forms in the soil. These performances may be beneficial to nodulation and BNF. The indigenous rhizobia that infect broad been were long-lived in the experimental soil. The efficiency of exogenous rhizobium inoculation may be unsatisfactory in the soils for frequently growing broad beans because of fierce competition with native rhizobia. Compared with no inoculation, the fungal inoculant increased nutrient (nitrogen, phosphorus, and potassium) availability in the fertilized soil, nodule mass, and plant BNF and nutrient uptake, leading to higher plant biomass and grain yield. Thus, C. lacerata HG2011 provided more potential sites for rhizobia infection in nodulation, increased nodule size, and improved nodule mineral nutrient (particularly phosphorus and iron) and photosynthate acquisitions, resulting in better nodulation and increased plant BNF. These significant findings firstly proved a new function of C. lacerata HG2011 in improving the inoculation and BNF of legume plants.

The reaction of soybean varieties to the use of a biological product

Relevance. In the conditions of the Central Black Earth region in the farm “Yaroslav the Wise” of the Starooskolsky district of the Belgorod region, five soybean varieties (Belgorodskaya 48, Bara, Victoria, Opus and Kassidi) were studied on nutritional backgrounds — without seed inoculation and without biological treatment (control), using only inoculation and with the use of a biological product against the background of seed inoculation.Methods. The experimental conditions differed in rainfall patterns and the amount of heat, their distribution was especially uneven in 2020, that had a significant negative effect on the yield of all studied soybean varieties. The soil of the experimental plot is typical medium-thick chernozem, medium-humus, heavy loamy texture. The advantages of the soybean variety Opus, the plants of which formed a large height, air-dry mass, leaf area, a greater number and mass of nitrogen-fixing nodules on the roots, were revealed. Plants of this variety provided a higher yield level in all studied agro-backgrounds.Results. The yield varied from 32,5 centners per hectare (control) to 36,2 centners per hectare (when using the biological product Biogor, Zh). The content and collection of protein were also higher in the Opus cultivar in all the studied agrophones. In comparison with the control, the protein content was higher by 4% (background — control), by 4,9% — with inoculation of seeds and by 6,1% — when using a biological product. The same pattern is observed when assessing the oil content in seeds and collecting protein and oil per hectare of soybean sowing. Inoculation of seeds with soybean inoculant Nitragin, KM improved plant development and increased productivity, as well as the profitability of cultivation of the studied soybean varieties, which was higher when using a biological product against the background of seed inoculation by an average of 27%, while with only inoculation — by only 15,1%.

Technology of effective microorganisms for the growth of agricultural plants of the Fabaceae family

This article presents the results of studies reflecting the influence of the technology of effective microorganisms (TEM) on the development of plants of the Fabaceae family (Pisum sativum L.). The assessment of the real effectiveness of EM agents in the mild climate of the Central Black Earth region and their influence on field germination and morphophysiological parameters of plants is given. The theoretical foundations of the use of EM agents, their role in the formation of soil microbiological communities and the assessment of their impact as a factor influencing the efficiency of legume-rhizobium symbiosis are presented. The exogenous treatment with biological products significantly increased the number and mass of active nodules on experimental plants, which contributed to the increase in nitrogen-fixing activity, which was an important component for legumes. The authors pay due attention to the assessment of the parameters of photosynthetic activity of plants under the conditions of increased inoculation with microorganisms. Not only an increase in leaf area was noted, but also a longer functioning of the photosynthetic apparatus, which led to an increase in the intensity of the work of the green surface of plants during the entire growing season. The combination of stimulating factors provided a better increase in dry biomass, which was reflected in a significant increase in the value of plant yield. The most intense accumulation of dry matter was observed in the flowering phase, which was also characterized by more intensive inoculation of plants. At the end of the growing season, this was reflected in an increase in the number of beans per plant and seeds in one bean, which had a positive effect on the crop yield indicators. The research results indicate the prospects of the use of the technology of effective microorganisms in plant growing and agriculture for the production of environmentally friendly food products and soil fertility recovery.

Biological nitrogen in increasing the productivity of beans (grains)

The results of a field experiment to study the effect of seed treatment with the biological product Rhizoactive (сompany BioNorma, Ukraine) on the formation and functioning of the symbiotic apparatus of common bean (grain) plants are presented.
 The experiment examined six varieties of common beans (grain), included in the State Register of plant varieties suitable for distribution in Ukraine: Bukovynka, Halaktyka, Slaviia, Ros, Otrada, Nata. The influence of bacterial fertilizer based on nodule bacteria " Rhizoactive " on the indicators of symbiotic and grain productivity of these varieties of common beans was studied.
 It was found, that the maximum number and raw weight of active nodules in the studied varieties of common beans were formed in the flowering phase. A larger number of nodules, compared to the variety Bukovynka (control), was formed on the root system of bean varieties Ros, Otrada and Nata. The maximum raw weight of rhizobia in the plots without the use of Rhizoactive was formed by the common bean variety Otrada – 0.297 g/plant of active nodules. Inoculation of the seeds of the studied common bean varieties with Rhizoactive increased the raw weight of active nodules in the flowering phase by 0.016–0.042 g/plant. A larger mass of nodules, compared to the Bukovynka variety, was formed on the root system of Ros, Otrada and Nata beans. The maximum raw weight of rhizobia in areas without the use of Rhizoactive was formed by the variety of beans Otrada – 0.297 g/plant of active nodules. Inoculation of seeds of the studied varieties of beans with Rhizoactive increased the raw weight of active nodules in the flowering phase by 0.016–0.042 g/plant.
 The highest increase in grain yield from seed inoculation was obtained in 2018, which was more favorable in terms of moisture. Thus, the largest increase in grain yield from the use of Rhizoactive was provided by the varieties Halaktyka (0.14 t/ha or 5.7 %), Ros (0.15 t/ha or 5.5 %) and Otrada (0.22 t/ha or 7.7 %). On average, in 2018–2020, inoculation of bean seeds with Rhizoactive, depending on the variety, provided an increase in grain yield from 2.4 to 6.7 %. And the highest level of bean grain yield on average in 2018–2020 was provided by the varieties Otrada (2.60 t/ha), Nata (2.50 t/ha) and Ros (2.40 t/ha) for inoculation of seeds with Rhizoactive

Metabolic Adjustment of Glycine max (L.) Merril in the Presence of Nitrate and Bradyrhizobium japonicum

Reactive oxygen species are generated during the processes of photosynthesis and nitrate reduction, which can compromise the integrity of biomolecules and membranes. During the vegetative phase of Fabaceae species, around half of translocated carbohydrate is used for nodule growth, while the other half returns to the aerial part with nitrogen incorporated. These sugars may be yet involved with membrane stabilization, signaling, and activation of important genetic pathways for plant development. Thus, the aim was to study the adjustments of the photosynthetic and antioxidant systems and the accumulation of carbohydrates and biomass in Glycine–Bradyrhizobium cultivated with nitrate (NO3−). Four treatments were evaluated in completely randomized blocks. Glycine–Bradyrhizobium was grown with 1.7 mM of NO3− (GB: 1.7 mM NO3−) and without NO3− (GB: 0 mM NO3−), and Glycine was grown with 1.7 mM of NO3− (G: 1.7 mM NO3−) and without NO3− (G: 0 mM NO3−). Glycine–Bradyrhizobium symbiosis contributes to photosynthetic metabolism and total sugars, reduces the action of antioxidant enzymes, and minimizes the use of nitrate in soybean cultivation.; Glycine–Bradyrhizobium with nitrate provided greater plant dry mass in the vegetative phase, along with increased enzymatic activity and reduced nodule mass.

Exploring phenotypic variation and associations in root nodulation, morphological, and growth character traits among 50 guar genotypes

Guar [Cyamopsis tetragonoloba (L.) Taub] is a legume grown worldwide, tolerant of hot, dry, and saline conditions. Phenotyping is a key bottleneck in guar improvement, with belowground root nodule phenes being largely overlooked. To address this bottleneck, a greenhouse study was conducted to evaluate phenotypic variability and associations in 14 nodule and plant growth parameters in 50 guar genotypes over 48 days. Nodule mass per plant differed among genotypes and had moderate heritability (P = 0.011, H2 = 0.40), while nodule number did not differ and had low heritability (P = 0.247, H2 = 0.14), and the parameters were not correlated. Nodule mass was correlated with total plant N (r = 0.56), plus most biomass parameters, indicating phenotypic links between plant capacity to support nodulation, N2 accumulation, and plant biomass production. Stem diameter may be useful as an indirect, high-throughput selection trait for increased nodulation in guar, as there was a positive association between stem diameter and nodule mass. Branch number and stem diameter, which have great agronomic significance, had wide phenotypic variability and were highly heritable. Reproductive development was delayed in branched genotypes, which may have implications in breeding guar for environments that differ in growing season length. Despite low heritability, there was a wide range in specific leaf area (SLA) that may be exploited by breeders to optimize drought tolerance and N use efficiency traits. These analyses give novel and confirmatory insights on the nature and associations of phenotypic character traits in guar, particularly nodule traits, providing added tools for breeders in developing desired and beneficial plant ideotypes.

Early nitrogen supplementation stimulates the nodulation and growth of common bean plants inoculated with rhizobium

The initial development of common bean plants (Phaseolus vulgaris L.) relying on symbiotic nitrogen (N) can be limited by delayed active N2 fixation, requiring supplemental N which in turn may inhibit the symbiosis. Five experiments were carried out in hydroponics to identify the initiation of nodulation and nitrogenase activity in common bean cultivars, and the effects of additions of mineral N on plant nodulation and growth. Three experiments evaluated the initial growth of five inoculated bean cultivars in the absence or presence of mineral N, and two experiments evaluated the effect of the moment of mineral N addition until the beginning of reproductive stage. The first root nodules appeared 10 days after plant transplant (DAT) and nitrogenase activity initiated 11 DAT. Cultivars of large seeds had lower initial nodulation and nitrogenase activity than those of small seeds. Inoculated plants showed limited shoot growth that lasted until 21-25 DAT as compared to inoculated plants receiving mineral N. Addition of mineral N reduced nodule mass more intensively than nodule number and more strongly nitrogenase activity. Nitrogen applied until 15 DAT enhanced nodulation and nitrogenase activity without limiting shoot growth, as compared to plants receiving N throughout their growth. Otherwise, plants that received N after 15 DAT had lower nodule mass and nitrogenase activity than plants only inoculated. The results indicate that symbiotic N did not suffice to an adequate growth of common beans and some supplemental N is necessary. This N should be added in the beginning of growth cycle to stimulate plant growth without inhibiting further nodulation and N fixation.

Nitrogen addition results in Medicago sativa switching nitrogen sources

Background Nitrogen (N) addition may have strong impacts on legume growth and their biological N fixation (BNF), but how legume N acquisition sources respond to N inputs have yet to be comprehensively assessed. Aims We quantified the effects of N addition on the growth and BNF of Medicago sativa and to assess the response of legume N acquisition to N addition. Methods We grew M. sativa in the greenhouse with NH4NO3 added at rates of 0, 2, 5, 10, 20, 50 g N m−2 yr−1, and analysed the variables that were relative to growth and N fixation, such as N concentration, biomass, δ15N values, nodule number, the percentage of plant N derived from symbiotic fixation of atmospheric N2 (Ndfa%). Results Nitrogen addition had marginal effects on plant biomass production (mean total biomass was 20.4 ± 1.6 and 22.3 ± 2.1 g pot−1 for the 0 and 50 g N m−2 yr−1 treatments, respectively) and foliar N concentration (4.6 ± 0.2% and 4.9 ± 0.1% for the same treatments). The δ15N value of the leaves increased with increasing added N, while Ndfa% decreased. The number of nodules formed also decreased with N addition while the number of nitrogenase (nifH) gene copies per unit nodule mass was not significantly different with N addition. Conclusions These findings indicate that increasing mineral N availability decreases symbiotic investment into BNF, mainly by reducing nodule formation; this was found to have no significant impact on plant growth because the plant changes its N source from BNF-N to mineral N derived from the soil.