Nodules Of Plants Research Articles

Effects of Inoculating Symbiotic Microorganisms on Acacia mangium Grown on Coconut Fiber

The ability of Acacia mangium to grow on degraded soils, thanks to its ability to fix atmospheric nitrogen, makes it a very important species in agroforestry and in the restoration of impoverished soils. However, all the experiments on Acacia mangium, whether inoculated or not, have only been carried out on a single type of substrate, i.e. soil. The aim was to determine whether inoculation significantly increased the biomass and height growth of Acacia mangium grown on coconut fiber. The experimental design comprised 5 treatments (Ta, T, M, R, and MR) with 5 replicates. Characterizing the coconut fiber and the dry biomass of Acacia mangium above ground and roots consisted of determining the content of elements such as P, K, Ca, Mg, and N. The number of nodules was also counted The results showed that inoculation (M, R and, MR) had no significant effect on the height growth and biomass of Acacia mangium. Non-inoculated (Ta and T) plants showed greater growth, probably due to the richness of nutrients (N, P) in the coconut fiber. The presence of nodules in the non-inoculated plants indicates the presence of indigenous strains in the coconut fiber. Double inoculation (mycorrhizae/rhizobia) significantly stimulated the growth and nodulation of Acacia mangium. Double inoculation also increased substrate fertility, which had a positive effect on plant growth. The Glomus-Bradyrhizobium combination appeared to be the most effective in improving the growth and nodulation of Acacia mangium.

Ionomic and proteomic changes highlight the effect of silicon supply on the nodules functioning of Trifolium incarnatum L.

Numerous studies have reported the beneficial effects of silicon (Si) in alleviating biotic or abiotic stresses in many plant species. However, the role of Si in Fabaceae facing environmental stress is poorly documented. The aim of this study is to investigate the effect of Si on physiological traits and nodulation efficiency in Trifolium incarnatum L. Si was supplied (1.7 mM in the form of Na2SiO3) plants inoculated with Rhizobium leguminosarum bv trifolii and plant physiological traits and nodule ionomic and molecular traits were monitored over 25 days. Si supply promoted shoot biomass, the quantity of both Si and N in roots and shoots, and the number, biomass and density of nodules and their nitrogenase abundance which contribute to better dinitrogen (N2) fixation. Ionomic analysis of nodules revealed that Si supply increased the amount of several macroelements (potassium, phosphorus and sulfur) and microelements (copper, zinc and molybdenum) known to improve nodulation efficiency and N2 fixation. Finally, comparative proteomic analysis (+Si versus -Si) of nodules highlighted that Si modulated the proteome of both symbionts with 989 and 212 differentially accumulated proteins (DAPs) in the infected host root cells and their symbiont bacteria, respectively. Among the DAPs, the roles of those involved in nodulation and N2 fixation are discussed. For the first time, this study provides new insights into the effects of Si on both nodular partners and paves the way for a better understanding of the impact of Si on improving nodule function, and more specifically, on the nodules' N2-fixing capacity.

Effect of Different Zn Concentrations on Crop Growth and Root Nodulation in Yard-Long Bean (Vigna unguiculata L.)

An experiment was conducted to study the effect of Zinc (Zn) as a micronutrient on growth and nodulation in Vigna unguiculata L. The experiment was carried out as a pot experiment in the Crop Farm, Faculty of Agriculture, Palachcholai, Eastern University, Sri Lanka from August to November 2023. The experiment was laid out in Complete Randomized Design with six treatments and four replicates. The treatments are T1 (Control), T2 (50 mg ZnSO4/kg soil), T3 (100 mg ZnSO4/kg soil), T4 (150 mg ZnSO4/kg soil), T5 (200 mg ZnSO4/kg soil) & T6 (250 mg ZnSO4/kg soil). The experiment used source of Zinc in the form of Zinc Sulphate (ZnSO4,5H2O) which yard-long bean plants can grow. The experiment results showed that, T2 treatment, the soil treated with 50 mg ZnSO4/kg soil significantly increase the Plant height, Chlorophyll content, Leaf area, Fresh weight of shoot & root, Dry weight of shoot & root, Number of nodules, Effective nodule percentage, as well as Soil respiration compared to the other treatments. However, beyond the level of 200 mg ZnSO4/kg soil, reduces the growth & nodulation of Vigna unguiculata L. and this shows that the level 200 mg ZnSO4/kg soil and beyond that level were the toxic level to the Vigna unguiculata L. Accordingly, the treatment T2 (50 mg ZnSO4/kg soil) was at the micronutrient level of Zn concentration which involved in many key cellular functions and show the best positive effect on growth and nodulation in Vigna unguiculata L. The results clearly indicate that, Zn can be use as a micronutrient up to a trace level in inducing plant growth and nodulation. However, at higher levels of Zn may act as heavy metal and cause phyto-toxicity in plants.

Efficacy of two different microbial consortia on salinity tolerance in chickpea: an in-planta evaluation on biochemical, histochemical, and genomic aspects.

This study aimed to identify and characterize actinobacteria and rhizobia with plant growth-promoting (PGP) traits from chickpea plants. Out of 275 isolated bacteria, 25 actinobacteria and 5 chickpea rhizobia showed 1-aminocyclopropane-1-carboxylate deaminase (ACCd) activity. Selected chickpea rhizobia were tested for their nodulating capacity under sterile and non-sterile soil conditions. Further screening on salinity and PGP traits identified three promising isolates: Nocardiopsis alba KG13, Sinorhizobium meliloti KGCR17, and Bacillus safensis KGCR11. These three isolates were analyzed for their compatibility and made into a consortium (Consortium 1). This along with another consortium made from our salinity-tolerant lab strains Chryseobacterium indologenes ICKM4 and Stenotrophomonas maltophilia ICKM15 (Consortium 2) was compared in planta studies. Trials revealed that Consortium 2 showed significant (p < 0.05) tolerance and on above-ground, below-ground traits and yield components than Consortium 1. Moreover, both consortia induced nodulation in saline-stressed plants, alleviated electrolyte leakage (2.3 vs. 0.4 in ICCV 2; 1.8 vs. 0.6 in JG 11), and increased chlorophyll content. Histochemical staining indicated reduced oxidative stress and lipid peroxidation in consortium-treated plants under salinity stress. Further, gene expression studies revealed mixed patterns, with up-regulation of antioxidant and transporter genes observed in consortium-treated plants, particularly in Consortium 2. Overall, Consortium 2 showed better gene expression levels for antioxidant and transporter genes, indicating its superior efficacy in mitigating salinity stress in chickpea plants. This study provides valuable insights into the potential use of these microbial isolates in improving chickpea productivity by enhancing salinity tolerance.

Effects of nano-MoO3 on growth, quality and toxicity of soybean.

Metal nanoparticles are widely used in agricultural production. As a new type of molybdenum fertilizer, MoO3NPs have the properties of nanomaterials and the characteristics of molybdenum nutrition. Previous studies have focused on their role in promoting crop growth. However, it is unknown whether excessive MoO3NPs will affect crop quality and nutritional value. In this study, the effects of different concentrations of MoO3NPs (0, 0.15, 0.5, 1.0, 5.0, 10, 50, 100 mg kg-1) on the growth and quality of soybean were investigated by pot experiments to analyze the plant effects caused by MoO3NPs. The results showed that the effects of MoO3NPs treatment on plant biomass and nodule number were promoted at low concentrations (0.15-5 mg kg-1) and inhibited at high concentrations (10-100 mg kg-1). According to the logistic distribution model, it was predicted that MoO3NPs would have the strongest toxic effect on soybean flowering stage. The contents of MoO3NPs which reduced the yield of soybean by 10% and 20% were 12.38 and 30.81 mg kg-1. NP0.15 could significantly improve the total amount of amino acids in grains, while NP100 reduced the total amount of amino acids in grains, both of them significantly increasing the contents of linolenic acid and linoleic acid in soybean seeds. A change of MoO3NPs concentration had no negative effect on the nutritional value of soybean grains. The research could lead to a better understanding of the potential impact of nutritional changes caused by MoO3NPs on human health. © 2024 Society of Chemical Industry.

The CEP peptide-CRA2 receptor module promotes arbuscular mycorrhizal symbiosis

C-terminally encoded peptides (CEPs) are small secreted signaling peptides that promote nitrogen-fixing root nodulation symbiosis in legumes, depending on soil mineral nitrogen availability.1 In Medicago truncatula, their action is mediated by the leucine-rich repeat receptor-like protein kinase COMPACT ROOT ARCHITECTURE 2 (CRA2).2,3,4 Like most land plants, under inorganic phosphate limitation, M.truncatula establishes another root endosymbiotic interaction with arbuscular fungi, the arbuscular mycorrhizal symbiosis (AMS). Because this interaction is beneficial for the plant but has a high energetic cost, it is tightly controlled by host plants to limit fungal infections mainly depending on phosphate availability.5 We show in this study that the expression of a subset of CEP-encoding genes is enhanced in the low-phosphate conditions and that overexpression of the low-phosphate-induced MtCEP1 gene, previously shown to promote the nitrogen-fixing root nodulation symbiosis, enhances AMS from the initial entry point of the fungi. Conversely, a loss-of-function mutation of the CRA2 receptor required for mediating CEP peptide action2 decreases the endomycorrhizal interaction from the same initial fungal entry stage. Transcriptomic analyses revealed that the cra2 mutant is negatively affected in the regulation of key phosphate transport and response genes as well as in the biosynthesis of strigolactone hormones that are required for establishing AMS. Accordingly, strigolactone contents were drastically decreased in cra2 mutant roots. Overall, we showed that the CEP/CRA2 pathway promotes both root nodulation and AMS in legume plants, depending on soil mineral nutrient availability.

NopP2 effector of Bradyrhizobium elkanii USDA61 is a determinant of nodulation in Vigna radiata cultivars

The symbiotic relationship between legumes and rhizobia is known to be influenced by specific rhizobial type III effectors (T3Es) in certain cases. In this study, we present evidence that the symbiosis between Vigna radiata and Bradyrhizobium elkanii USDA61 is controlled by a T3E called NopP2, and this interaction is highly dependent on the genetic makeup of the host plant. NopP2 plays a crucial role in promoting nodulation in various V. radiata varieties. Additionally, NopP2 is essential for early infection and the formation of nodules in compatible plants. Through evolutionary analysis, we discovered that bradyrhizobial NopPs can be categorized into two distinct clusters: NopP1 and NopP2. Furthermore, both types of bradyrhizobial NopPs were conserved within their respective groups. Our findings suggest that NopP2 serves as a mechanism for optimizing the symbiotic relationship between V. radiata and B. elkanii USDA61 by interacting with the pathogenesis related-10 (PR10) protein and reducing effector-triggered immunity (ETI) responses.

Potential of novel Rhizobium strains as biofertilizer for improved groundnut (Arachis hypogaea L.) cultivation in Eastern India

ABSTRACT Comprehensive assessments were conducted on eight fast growing, novel Rhizobium isolates, short listed from a preliminary selection of 68 isolates obtained from root nodules of groundnut plants grown in diverse agro-climatic regions of eastern India. Additionally, two conventional rhizobia strains, viz. IGR6 and GN2, (collected from the Nodule Research Center, BCKV), were utilized for comparative analysis. Cluster analysis, based on carbon utilization and biochemical parameters, grouped all the test isolates with an average similarity level of 73%. The ability of the isolates to utilize a wide range of carbon sources, including hexoses, pentoses, and disaccharides, confirms their fast-growing nature. Further analysis through 16S rDNA extraction and nucleotide sequencing revealed that the promising fresh isolates exhibited 95–99% similarity to known Rhizobium species in public databases. When evaluated in pot culture experiments using new alluvial soil from the Gangetic Plains in eastern India, the native fresh isolate NRA1(PP355674) outperformed other isolates and conventional strains in terms of nodulation efficiency, plant dry matter production, and plant nitrogen uptake. This study highlights the significant potential of native Rhizobium isolates to surpass conventionally used strains in biological nitrogen fixation, supporting the development of sustainable, environmentally-friendly, and cost-effective agricultural practices.

TML1 AND TML2 SYNERGISTICALLY REGULATE NODULATION AND AFFECT ARBUSCULAR MYCORRHIZA IN MEDICAGO TRUNCATULA.

Two symbiotic processes, nodulation and arbuscular mycorrhiza, are primarily controlled by the plant's need for nitrogen (N) and phosphorus (P), respectively. Autoregulation of Nodulation (AON) and Autoregulation of Mycorrhization (AOM) both negatively regulate their respective processes and share multiple components - plants that make too many nodules usually have higher AM fungal root colonization. The protein TML (TOO MUCH LOVE) was shown to function in roots to maintain susceptibly to rhizobial infection under low N conditions and control nodule number through AON in Lotus japonicus . M. truncatula has two sequence homologs: Mt TML1 and Mt TML2. We report the generation of stable single and double mutants harboring multiple allelic variations in MtTML1 and MtTML2 using CRISPR-Cas9 targeted mutagenesis and screening of a transposon mutagenesis library. Plants containing single mutations in Mt TML1 or Mt TML2 produced 2-3 times the nodules of wild-type plants whereas plants containing mutations in both genes displayed a synergistic effect, forming 20x more nodules compared to wild type plants. Examination of expression and heterozygote effects suggest genetic compensation may play a role in the observed synergy. Plants with mutations in both TMLs only showed mild increases in AM fungal root colonization at later timepoints in our experiments, suggesting these genes may also play a minor role in AM symbiosis regulation. The mutants created will be useful tools to dissect the mechanism of synergistic action of Mt TML1 and Mt TML2 in M. truncatula symbiosis with beneficial microbes.

Study of Plant Growth Promoting Abilities of Rhizobium Strains Isolated from Mungbean Root Nodules

Background: Plant Growth Promoting Rhizobacteria (PGPR) are a type of bacteria that use biofertilizers and other plant growth-promoting agents to increase plant output and growth. In the last several decades, there has been a global surge in the usage of beneficial soil microorganisms like PGPR for safe and sustainable agriculture due to the detrimental effects of artificial fertilizers on the environment and their rising prices. Plant-beneficial rhizobacteria have the potential to reduce the world's reliance on dangerous agricultural chemicals that upset agro-ecosystems. Today a large part of yield is lost due to the various stress mechanisms of plants. It could be classified into biotic and abiotic stress. These are generally a group of microorganisms that is found either in the rhizosphere or in the root nodules of plants. PGPR has beneficial impact, they colonize in the plant roots and improve crop yields and agricultural productivity and also produce some useful growth promoting growth hormones viz., IAA, Auxins, Cytokinin and Gibberellins. Methods: The bacterial isolates were screened for plant growth promoting traits such as phosphate solubilization, IAA production and siderophore production was tested qualitatively by using pikovskayas media, TSB (Tryptone Soy Broth) agar and Chrome Azurol Sulphate (CAS) blue agar respectively. Results: In present study out of the eight rhizobial isolates, five exhibited the phosphate solubilization zones, three shows negative result. However out of eight isolates five isolates produced IAA and three showed negative result. Among all isolates seven isolates were able to produce siderophore, while one showed negative result.

Growth and Yield of Lentil as Influenced by Zinc and Boron Management

A field experiment was conducted at Sher-e-Bangla Agricultural University, Dhaka-1207, Bangladesh, during the period from November 2021 to March 2022 to evaluate the influence of micronutrients management on growth and yield of two lentil varieties viz., BARI Masur-8 (V1) and Binamasur-8 (V2) and 6 micronutrients management (no fertilizer - F1, recommended fertilizer dose (RFD) (40-90-40-55 Kg ha−1 of urea-TSP-MoP-Gypsum) with 10 Kg ha−1 ZnSO4 as basal - F2, RFD with zinc (Zn) as foliar spray - F3, RFD with Zn and boron (B) as foliar spray - F4, 50% RFD + 50% cow dung (5 t ha−1) - F5 and 50% RFD + 50% cow dung + Zn and B as foliar spray - F6). No significant effect had found for variety except 1000-seed weight but micronutrients management along with interactions significantly effects on all studied parameters of lentil. The higher 1000-seed weight (34.16 g) was recorded in BARI Masur-8. The highest plant height (37.09 cm), number of branches plant−1 (7), dry weight of root plant−1 (159.17 mg), dry weight of shoot plant−1 (3319.33 mg) and number of pods plant−1 (62) was observed at F6 treatment. The highest 1000-seed weight (31.68 g) were recorded at F2 treatment. The highest weight of nodules plant−1 (10.33 mg at 60 DAS), seed yield (2.62 t ha−1), straw yield (2.12 t ha−1) and biological yield (4.74 t ha−1) were found at F3 treatment. The highest plant height (38.45 cm), number of branches plant−1 (7), number of pods plant−1 (63), seed yield (2.91 t ha−1) and harvest index (58.65%) were recorded at V2F6 whereas the highest weight of nodules plant-1 (26 mg), straw yield (2.22 t ha−1) and biological yield (5.02 t ha−1) were found at V1F3 but the highest 1000-seed weight (34.87 g) at V1F1. The highest number of seeds pod−1 (1.83) was found at V2F1. So, two varieties showed similar performance on yield. Foliar application of Zn has the potentiality to increase seed yield. The variety Binamasur-8 with 50% RFD + 50% cow dung + Zn and B (F6) as foliar spray could bring maximum yield (2.91 t ha−1) of lentil followed by treatment F2, F3, and F4. Bangladesh Agron. J. 2024, 26(2): 34-40

Microbiological mechanism of hydrogen fertilizer effect in soil.

For a long time, intercropping and rotation of leguminous with non-leguminous crops is widely used to reduce the application of nitrogen fertilizer and increase yield in agroecosystems. At present, most researchers considered that this management measure is helpful for reducing fertilizer consumption and increasing its efficiency, as it can improve nutrient supply of legumestonon-legumes, the spatial nutrient utilization efficiency by enhancing soil spatial heterogeneity, and improve soil structure and disease resistance. However, current theories cannot fully explain the positive effect of crop rotation and inter-cropping systems involving legumes. A large amount of hydrogen (H2) can be produced as an obligatory by-product of nitrogenase responsible for nitrogen (N2) fixation in the root nodules of leguminous plants. Despite of substantial amounts of H2 enriched in the rhizosphere of legumes, only a minor proportion of H2 is found to leak to soil surface. Increasing evidence showed that most H2 released in soil is immediately depleted in the surrounding of N2-fixing nodules by H2-oxidizing bacteria (HOB) thriving in soil. HOB can use H2 as an electron donor to assimilate and fix CO2 through redox reactions to synthesize cellular substances and consequently promote plant growth. To date, however, little is known about the biological mechanism and ecological process behind the "hydrogen fertilizer effect". Therefore, we review the H2-induced plant growth-promoting effects and its microbiological mechanisms. Our aims were to explore a new way for enhancing agroecosystem production, and to provide scientific basis for future utilization of H2 in agricultural production practices.

Use of image analysis in the evaluation of radicular nodules in chickpeas

The use of advanced computational systems facilitates the application of a wide range of statistical techniques, available in open-source format, to perform analyses of substantial complexity in biological systems, particularly in the field of plant biology. The aim of this study is to demonstrate the application of image analysis in the evaluation of root nodules in Cicer arietinum plants. The research was conducted in the field, where roots were collected, subjected to rigorous cleaning protocols and subsequently photographed under precisely controlled studio conditions. This photographic process was performed using equipment configured with meticulous parameter settings. Subsequently, image analyses were performed using the statistical software package, R. Parameters of interest were quantified, including metrics such as root area, nodule area, the proportional representation of nodules in relation to the total root mass and the absolute count of nodules present. A critical comparison between the proposed analytical methodology and conventional approaches evidenced a substantial improvement in efficiency, thus highlighting the robustness and validity of this analytical framework for the outlined research objectives. Therefore, the developed methodology has significant potential to facilitate accurate and comprehensive analyses of nodules and root systems, thus making a notable contribution to fostering a deeper understanding and exploration of plant-microorganism interactions. Furthermore, this methodological advancement has the potential to contribute to reducing operational costs and optimizing the time spent on such meticulous evaluative undertakings.

Interactive Effects of Boron and Molybdenum on Nodulation, Growth and Yield of Cowpea under South Gujarat Condition

Background: Cowpea seeds are nutritious component of human diet and being a legume crop, it also improves the soil fertility by increasing the amount of nitrogen in the soil through symbiotic nitrogen fixation. To study the effect of boron and molybdenum on nodulation, growth and yield of cowpea the field experiment was conducted at the Regional Horticultural Research Station, Navsari Agricultural University, Navsari, Gujarat, India, during summer season of 2019 and 2021. Methods: The experiment was carried out in a factorial randomized block design with 3 replications. Factor-1 consisted of four levels of seed treatments with molybdenum at 2 mg/l (M1), 4 mg/l (M2), 6 mg/l (M3) for 24 hours prior to sowing including control (M0), where as the second factor was consisted of four levels of boron (B) spray at 2 mg/l (B1), 4 mg/l (B2), 6 mg/l (B3) and control at 30 DAS, 45 DAS and 60 DAS with control. Boron was applied in the form of Boric acid and Molybdenum as ammonium molybdate. Result: The treatment combination of seed treatment of molybdenum @ 2 mg/ l with foliar spray of boron @ 4 mg/ l at 30, 45 and 60 DAS (M1B2) has significantly influenced yield parameters and registered maximum number of clusters per plant (6.50), green pod yield per plant (0.153 kg), green pod yield per net plot (3.98 kg), green pod yield per hectare (12.27 tonne). Seed treatment with different levels of molybdenum has significantly influenced nodulation in cowpea and recorded maximum number of nodules per plant (31.69 at final harvest) and fresh nodule weight (0.230 g/plant) in seed treatment of molybdenum @ 2 mg/ l (M2) among all the treatments at final harvest during all the years of study, including pooled analysis.

Soybean inoculation with Azospirillum argentinense improves nodulation, grain yield, and alleviates the incidence of Fusarium at field with drought stress

ABSTRACT The efficacy of Azospirillum argentinense REC3, applied by seed inoculation, in enhancing soybean (Glycine max [L.] Merr.) nodulation with native rhizobia, improving grain yield, and protecting against Fusarium fungi was studied. In La Cruz, Tucumán, Argentina, 23 fungal isolates were identified as F. oxysporum (2 strains), F. solani (2), and F. tucumaniae (19). Following soil infestation, only F. tucumaniae was confirmed as a phytopathogen, with REC3 inhibiting its mycelial growth. Greenhouse trials, for a duration of 30 days, showed significant reductions in disease severity (78.2%), root rot (32.3%), and disease incidence (50.9%) in plants susceptible to sudden death syndrome (SDS) when REC3 was applied. Field experiments (2018–2019; January-April) under drought stress conditions, displayed increased nodulation (37.2%) and grain yield (2077 ± 272.8 kg ha−1, p < 0.05) in REC3-treated plants compared to controls (1516 ± 272.8 kg ha−1, p < 0.05). Additionally, a low disease incidence (0.90%) was observed only in the SDS-susceptible soybean variety without REC3 treatment. Overall, the findings showed the significant potential of REC3 inoculation as a biotechnological strategy for enhancing agricultural productivity, managing diseases, and improving crop resilience under challenging environmental conditions. This integrated approach, combining the use of a partially SDS-resistant soybean variety with REC3 inoculation, showed promise in protecting soybean cultivation against SDS and other fungal diseases, thereby ensuring more sustainable and resilient agricultural practices.

Adaptation of Rhizobium leguminosarum sv. trifolii strains to low temperature stress in both free-living stage and during symbiosis with clover

Legume-rhizobial symbiosis plays an important role in agriculture and ecological restoration. This process occurs within special new structures, called nodules, formed mainly on legume roots. Soil bacteria, commonly known as rhizobia, fix atmospheric dinitrogen, converting it into a form that can be assimilated by plants. Various environmental factors, including a low temperature, have an impact on the symbiotic efficiency. Nevertheless, the effect of temperature on the phenotypic and symbiotic traits of rhizobia has not been determined in detail to date. Therefore, in this study, the influence of temperature on different cell surface and symbiotic properties of rhizobia was estimated. In total, 31 Rhizobium leguminosarum sv. trifolii strains isolated from root nodules of red clover plants growing in the subpolar and temperate climate regions, which essentially differ in year and day temperature profiles, were chosen for this analysis. Our results showed that temperature has a significant effect on several surface properties of rhizobial cells, such as hydrophobicity, aggregation, and motility. Low temperature also stimulated EPS synthesis and biofilm formation in R. leguminosarum sv. trifolii. This extracellular polysaccharide is known to play an important protective role against different environmental stresses. The strains produced large amounts of EPS under tested temperature conditions that facilitated adherence of rhizobial cells to different surfaces. The high adaptability of these strains to cold stress was also confirmed during symbiosis. Irrespective of their climatic origin, the strains proved to be highly effective in attachment to legume roots and were efficient microsymbionts of clover plants. However, some diversity in the response to low temperature stress was found among the strains. Among them, M16 and R137 proved to be highly competitive and efficient in nodule occupancy and biomass production; thus, they can be potential yield-enhancing inoculants of legumes.

Evaluation of methods for inoculating soybean seeds with Bradyrhizobium spp. and Azospirillum brasilense in the plant nodulation and productivity

Evaluation of methods for inoculating soybean seeds with Bradyrhizobium spp. and Azospirillum brasilense in the plant nodulation and productivity

Impact of alternate partial root-zone irrigation on the rhizosphere microbiota of alfalfa plants inoculated with rhizobia.

Water is an important constraint on alfalfa (Medicago sativa) production in arid and semiarid areas, and alternate irrigation in root areas has water-saving potential for alfalfa production. To investigate the impact of alternate partial root-zone irrigation (APRI) on the rhizosphere soil microorganisms of alfalfa, this study subjected alfalfa plants to different irrigation methods and irrigation levels. The growth status and rhizosphere soil microbial community diversity of alfalfa plants under alternate root-zone watering treatment were analyzed through laboratory experiments and high-throughput sequencing. The results showed that at soil moisture levels of 80% field moisture capacity (FMC) and 60% FMC, APRI had no significant impact on the biomass or nodule number of alfalfa. However, 40% FMC significantly reduced the individual plant dry weight, chlorophyll content, and nodule number of the alfalfa plants. APRI increased the relative abundance of Actinomycetes in the alfalfa rhizosphere soil. Moreover, at 60% FMC, the MBC and MBN of rhizosphere, relative abundance of Actinobacteria and unclassified K fungi and Chao 1 index of bacteria significantly increased under APRI treatment. While relative abundance of Ascomycetes and Proteobacteria in the alfalfa rhizosphere significantly reduced under 60% FMC + APRI treatment. In summary, under the same irrigation conditions, APRI did not significantly affect the growth of alfalfa in the short term. And 60%FMC + APRI treatment did significantly affect the groups, structure and diversity of the rhizosphere soil microbial communities.

Mesorhizobia strain and chickpea variety drive phenotypic plasticity of plant growth and nodulation

Chickpea (Cicer arietinum) establishes symbiotic relationships with several Mesorhizobium species and the three-way interaction between chickpea variety, Mesorhizobium strain, and environment, drives plant growth and nitrogen fixation. Here we quantified the phenotypic plasticity for shoot dry weight, nodule dry weight, nodules per plant, nodule colour, symbiotic effectiveness, and nitrogen cost in a factorial experiment combining five chickpea varieties, seven Mesorhizobium strains and three photothermal regimes. Plant growth and nitrogen fixation traits varied with variety, Mesorhizobium strain, photothermal environment and their interaction. Phenotypic plasticity was larger for nodules per plant (7.3-fold) than for shoot dry weight (2.7-fold), verifying a hierarchy of plasticities between these traits. Strain-driven plasticity of plant growth and nitrogen fixation traits was larger than variety-driven plasticity for our combination of varieties, strains, and photothermal environments, with strain-driven phenotypic plasticity being 2.7-fold vs 1.4-fold for shoot dry matter, 2.5-fold vs 1.7-fold for nodule dry weight, 7.3-fold vs 2.1-fold for nodules per plant, 3.7-fold vs 1.7-fold for nodule color, 2.9-fold vs 1.6-fold for symbiotic effectiveness, and 2.3-fold vs 1.6-fold for nitrogen cost. Our study provides insights on the phenotypic plasticity of the legume-rhizobia interaction by considering the plants as part of the rhizobia environment and vice-versa.

Maximizing Productivity and Profitability of Green Gram (Vigna radiata L.) through Fertility Levels and Bio Fertilizers

A field experiment was conducted at the Crop Research Centre, School of Agriculture, ITM University Gwalior (M.P.) during the Kharif season of 2023 to evaluate the maximizing productivity and profitability of green gram (Vigna radiata L.) through fertility levels and biofertilizers. The experiment was laid out in a randomized block design with 10 treatment combinations and each treatment was replicated thrice. The results revealed that the application of 100% RDF + RSI (10 g kg⁻¹) + PSB &amp; KSB (5 kg ha⁻¹ each) had significantly improved the growth attributes viz., Plant height, number of branches, dry matter accumulation, Leaf area index and number of nodules plant⁻¹ of green gram over rest of the treatments. However, the higher grain yield (1424.71 kg ha-1), straw yield (3206.13 kg ha­­⁻¹) and biological (4630.84 kg ha­­⁻¹) yield was recorded with the treatment 100% RDF + RSI (10 g kg⁻¹) + PSB &amp; KSB (5 kg ha⁻¹ each) which was being at par with 100% RDF + RSI (10 g kg⁻¹) + PSB 5 kg ha⁻¹ soil application, while the lowest grain yield and straw yield were recorded in control.