Stimulate Plant Growth Research Articles

Synthesis and Degradation of the Phytohormone Indole-3-Acetic Acid by the Versatile Bacterium Paraburkholderia xenovorans LB400 and Its Growth Promotion of Nicotiana tabacum Plant

Plant growth-promoting bacteria (PGPB) play a role in stimulating plant growth through mechanisms such as the synthesis of the phytohormone indole-3-acetic acid (IAA). The aims of this study were the characterization of IAA synthesis and degradation by the model aromatic-degrading bacterium Paraburkholderia xenovorans LB400, and its growth promotion of the Nicotiana tabacum plant. Strain LB400 was able to synthesize IAA (measured by HPLC) during growth in the presence of tryptophan and at least one additional carbon source; synthesis of anthranilic acid was also observed. RT-PCR analysis indicates that under these conditions, strain LB400 expressed the ipdC gene, which encodes indole-3-pyruvate decarboxylase, suggesting that IAA biosynthesis proceeds through the indole-3-pyruvate pathway. In addition, strain LB400 degraded IAA and grew on IAA as a sole carbon and energy source. Strain LB400 expressed the iacC and catA genes, which encode the α subunit of the aromatic-ring-hydroxylating dioxygenase in the IAA catabolic pathway and the catechol 1,2-dioxygenase, respectively, which may suggest a peripheral IAA pathway leading to the central catechol pathway. Notably, P. xenovorans LB400 promoted the growth of tobacco seedlings, increasing the number and the length of the roots. In conclusion, this study indicates that the versatile bacterium P. xenovorans LB400 is a PGPB.

Preparation of lignosulphonate nanoparticles and their applications in dye removal and as plant growth stimulators

Preparation of lignosulphonate nanoparticles and their applications in dye removal and as plant growth stimulators

Impact of gibberellic acid GA3, quantum dot biochar, and rhizosphere bacteria on fenugreek plant growth and stress responses under lead stress

Lead (Pb) is a stress that can cause problems with several aspects of a plant’s metabolism, potentially impeding the plant’s ability to grow and develop. The use of gibberellic acid (GA3), quantum dot biochar (QDBC), and rhizobacteria (RB) can be effective methods to overcome this problem. Gibberellic acid is a crucial plant hormone that regulates plant growth, cell division, tissue differentiation, flowering, photosynthesis, and transpiration rate. It also significantly impacts crop resilience to stress, affecting plant morphology, enzymatic activity, and physiology. Biochar, a soil supplement, enhances plant development soil health, and reduces stress effects. Due to its large surface area and porosity, it increases soil water-holding capacity, nutrient retention, and microbial activity. Quantum dots, semiconductor nanoparticles, have been proposed as a potential method to alleviate plant stress by acting as antioxidants, reducing oxidative stress, and controlling nutrient and growth regulators. Rhizobacteria, soil bacteria in plant roots, stimulate plant growth, nutrient absorption, and harvesting capacity. They produce phytohormones, increase mineral and nitrogen accessibility, and can induce systemic resistance (ISR), affecting plant defense. This study investigates the effects of combining GA3, QDBC, and RB as amendments to fenugreek, both with 500 Pb stress and without Pb stress. Treatments (control, 0.25 GA3mg/L-QDBC, 0.5 GA3mg/L-QDBC, 0.25 GA3mg/L-QDBC + RB, and 0.5 GA3mg/L-QDBC + RB) were applied in six replications using a completely randomized design. Results demonstrate that the combination of 0.5 GA3mg/L-QDBC + RB with 500 Pb stress led to significant enhancements in fenugreek shoot fresh weight (15.62%), root fresh weight (73.53%), shoot dry weight (24.00%), and root dry weight (36.53%) compared to the control. Additionally, there were notable improvements in chlorophyll a (57.23%), chlorophyll b (19.21%), and total chlorophyll (36.23%) compared to the control under Pb stress, also showing the potential of 0.5 GA3mg/L-QDBC + RB with 500 Pb stress. The study suggests that combining 0.5 GA3mg/L-QDBC + RB with 500 Pb stress can effectively mitigate Pb stress in fenugreek.

Enhancing Soil Microbial Activity and Spelt (Triticum spelta L.) Yield in Organic Farming Through Biofertilizer and Green Manure Applications

At present, there is growing consumer interest in Triticum spelta L., which has high nutritional value. This species is recommended for cultivation in organic farming. In this system of agriculture, biofertilizers are an alternative to mineral fertilization. Biofertilizers stimulate plant growth by providing nutrients through the biological fixation of molecular nitrogen from the air or by increasing the availability of insoluble nutrients in the soil and by synthesizing substances that stimulate plant growth. Green manure biomass and root secretions provide growth material for soil microorganisms, and microorganisms return nutrients to the soil and plants through nutrient decomposition and conversion. Considering the many benefits of using biofertilizers and growing cereals with cover crops for green manure in cereal rotations, field research was carried out on an organic farm to evaluate the soil microbes and the amount of biomass from green manures and their follow-up effect on Triticum spelta L. yields using biofertilizers. Two factors were researched: (I) biofertilizers: control object (no biofertilizer), Azotobacter chroococcum + Azospirillum lipoferum Br 17, Arthrobacter agilis + Bacillus megaterium var. phosphaticum, and combined application of atmospheric nitrogen-fixing bacteria with phosphate solubilizing bacteria; (II) green manures: control object (no green manure application), Trifolium pratense L., Trifolium pratense L. + Lolium multiflorum L., and Lolium multiflorum L. The results show that the most favorable abundance of microorganisms determined in the soil after harvesting Hordeum vulgare L. was recorded after the application of biofertilizers containing atmospheric nitrogen-fixing bacteria with phosphate-solubilizing bacteria under a mixture of Trifolium pratense L. with Lolium multiflorum L. Plowing green manure from a mixture of Trifolium pratense L. with Lolium multiflorum L. resulted in an average increase of 39% in grain yield of Triticum spelta L., while the application of a biofertilizer containing Azotobacter chroococcum + Azospirillum lipoferum Br 17 + Arthrobacter agilis + Bacillus megaterium var. phosphaticum resulted in an average increase of 63%. The proposed spelt wheat cultivation technique can be recommended for agricultural practice due to the positive response of grain yield, but it may also be an important direction for further research to reduce the negative impact of agriculture on the environment.

Bacterial allantoin mediated optimally biosynthesized silver nanoparticles exhibit antioxidant, antibacterial, and seed germination promoting activities

The biosynthesis of silver nanoparticles (AgNPs) presents a sustainable, cost-effective, and scalable alternative to conventional synthesis techniques. This study investigates microbial allantoin as a biogenic reducing agent for the synthesis of AgNPs, emphasizing their antioxidant, antibacterial, and seed germination enhancement properties. Optimally synthesized allantoin-mediated AgNPs exhibited a crystalline size of 3.66 nm with a band gap energy of 3.39 eV. Scanning Electron Microscopy (SEM) analysis showed spherical nanoparticles with an average particle size of 84 nm, while particle size analysis revealed a zeta potential of −26.7 mV and a hydrodynamic diameter of 137.1 nm. The AgNPs displayed significant free radical scavenging activity, achieving 58% and 70% inhibition in H₂O₂ and DPPH assays, respectively. Furthermore, these AgNPs demonstrated substantial antibacterial activity against both Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa. Additionally, allantoin-mediated AgNPs promoted germination in Cicer arietinum seeds within 48 h, indicating their potential as plant growth stimulants. This pioneering study on microbial allantoin-derived AgNPs suggests promising applications across pharmaceuticals, environmental science, and cosmetic fields.

Evaluation of commercial rhizobacteria-based bio-inoculants for the control of the false root-knot nematode Nacobbus aberrans sensu lato and the promotion of pepper plants

ABSTRACT Nacobbus sp. is a phytoparasitic nematode that affects economically important crops. Due to the negative environmental and health impacts of chemical nematicides, sustainable alternatives, such as the use of biological control agents, are being developed. Rhizobacteria are microorganisms that can suppress nematode reproduction by producing different metabolites, induce systemic resistance in plants and stimulate plant growth. The aim of this study was to investigate whether the inoculation with commercial formulations of plant-growth promoting rhizobacteria (PGPR) can mitigate the deleterious effects of the nematode N. aberrans s.l. and promote the growth of pepper plants grown in greenhouses under biotic stress. Different bacteria were tested in vitro before being inoculated into pepper plants. Plants were inoculated with Bacillus subtilis, Bacillus thuringiensis and Azospirillim brasilense at transplant and then every 15 days, in the presence and absence of N. aberrans s.l.. The pathogen reproduction factor was 5.34; 2.09; 0.88 and 12.46 for A. brasilense B. subtilis, B. thuringiensis and control, respectively. In both nematode-parasitized and unparasitized plants, the rhizobacteria increased the soluble proteins (54%) and chlorophyll (18%) content and exerted a positive effect on net photosynthesis, transpiration, stomatal conductance and increased water use efficiency, height, stem diameter, fresh and dry weight. This beneficial effect was also verified by a lower accumulation of proline and sugars, metabolites used by plants as osmoregulators in stress situations. These results showed that B. thuringiensis and B. subtilis perform better in promoting pepper growth in the presence of the nematode and in the biocontrol of this pathogen.

Optimization of Sargassum bovianum Extraction Techniques for Germination of Wheat, Canola, and Corn Under Different Salinity Stress

Seaweeds are a cheap, eco-friendly, and rich source of plant growth stimulators that can mitigate the adverse effects of salinity stress. This study examined the impact of Sargassum bovianum extracts obtained through different techniques using pressure, heat, and microwave radiations on the germination and growth of wheat, corn, and canola seeds under varying salinity levels (500, 3500, and 6500 µS cm−1). The findings showed that pressure, microwave, and acidic extraction methods were the most effective in extracting polysaccharides, alginate, and nutrients from S. bovianum. Seaweed extract significantly improved the mean germination time (MGT) and germination index (GI) of wheat under high salinity stress and had a positive effect on wheat plumule length (PL) and germination percentage (GP). However, seaweed extract had no significant impact on canola seeds in salinity stress, except for improved canola PL. The PL and seedling vigor index (SVI) of corn were enhanced in low salinity levels, but most treatments reduced PL and SVI in high salinity. This study suggests that using heat, pressure, and microwave techniques for seaweed extraction results in higher polysaccharides and alginate content, leading to improved germination and plant growth, particularly in wheat and canola. These findings can help growers optimize the germination and growth of these important crops.

Ecological restoration enhances dryland carbon stock by reducing surface soil carbon loss due to wind erosion

Enhancing terrestrial carbon (C) stock through ecological restoration, one of the prominent approaches for natural climate solutions, is conventionally considered to be achieved through an ecological pathway, i.e., increased plant C uptake. By conducting a comprehensive regional survey of 4279 1 × 1 m2 plots at 517 sites across China's drylands and a 13-y manipulative experiment in a semiarid grassland within the same region, we show that greater soil and ecosystem C stocks in restored than degraded lands result predominantly from decreased surface soil C loss via suppressed wind erosion. This biophysical pathway is always overlooked in model evaluation of land-based C mitigation strategies. Surprisingly, stimulated plant growth plays a minor role in regulating C stocks under ecological restoration. In addition, the overall enhancement of C stocks in the restored lands increases with both initial degradation intensity and restoration duration. At the national scale, the rate of soil C accumulation (7.87 Tg C y-1) due to reduced wind erosion and surface soil C loss under dryland restoration is equal to 38.8% of afforestation and 56.2% of forest protection in China. Incorporating this unique but largely missed biophysical C-conserving mechanism into land surface models will greatly improve global assessments of the potential of land restoration for mitigating climate change.

Application of Chitosan and Its Derivatives Against Plant Viruses.

Chitosan is a natural biopolymer that is industrially produced from chitin via deacetylation. Due to its unique properties and a plethora of biological activities, chitosan has found application in diverse areas from biomedicine to agriculture and the food sector. Chitosan is regarded as a biosafe, biodegradable, and biocompatible compound that was demonstrated to stimulate plant growth and to induce a general plant defense response, enhancing plant resistance to various pathogens, including bacteria, fungi, nematodes, and viruses. Here, we focus on chitosan application as an antiviral agent for plant protection. We review both the pioneer studies and recent research that report the effect of plant treatment with chitosan and its derivatives on viral infection. Special attention is paid to aspects that affect the biological activity of chitosan: polymer length and, correspondingly, its molecular weight; concentration; deacetylation degree and charge; application protocol; and experimental set-up. Thus, we compare the reported effects of various forms and derivatives of chitosan as well as chitosan-based nanomaterials, focusing on the putative mechanisms underlying chitosan-induced plant resistance to plant viruses.

Assessing the efficacy of Arthrospira maxima biofertilizers and commercial alternatives on cash crop growth

AbstractBiofertilizers offer a sustainable alternative to chemical fertilizers, notorious for their harmful impact on the environment and human health. Sources of biofertilizers include cyanobacteria, such as those from the genus Arthrospira, which contain bioactive compounds that enhance plant growth directly and indirectly. To promote widespread biofertilizer adoption, experimental trials are essential to compare their efficacy against chemical fertilizers and different biofertilizer varieties. Some biofertilizers rely on ultrasonication for cell rupture, but since A. maxima undergoes sun‐drying to obtain the biomass powder, which also ruptures cells, ultrasonication may be unnecessary. We assessed the biofertilizer capabilities of Arthrospira maxima (Setchell & N.L. Gardner) Geitler biomass on three cash crops, banana (Musa acuminata Colla), cowpea (Vigna unguiculata L. Walp.), and eggplant (Solanum melongena Mill. Dunal). We compared sonicated and non‐sonicated biomass (both 20 g L−1) against a commercially available, brown algae Ascophyllum nodosum (L.) biofertilizer (4 mL L−1 OptiMar), a commercially available chemical fertilizer (1.5 mL L−1 Triple15), and a negative control of tap water. Few differences were observed among A. maxima treatments, suggesting sonication might be unnecessary. OptiMar, Triple15, and the negative control did not yield the highest biometric values of any trait in any crop. If commercially available fertilizers and biofertilizers do not outperform the negative control, it raises crucial questions regarding their effectiveness and the appropriate concentrations at which they should be applied. Non‐sonicated biomass often outperformed OptiMar, Triple15, and the negative control, demonstrating the potential Arthrospira maxima has for stimulating plant growth without ultrasonication.

Growth and production of Pakcoy plant (Brassica rapa L.) by giving NPK fertilizers and biosaka

Abstract Optimizing in using agricultural production materials is important to be paid attention to in order to support food security and global climate change. The progressive application NPK fertilizer application can also increase growth and vegetable yields, supported by the application of biosaka which is a plant extract liquid containing low levels of phytohormones and secondary metabolites. Its function is to stimulate plant growth and increase plant resistance to pests and diseases. This research studied the growth and production of Pakcoy (Brassica rapa L.) by applying NPK fertilizer and biosaka, held in Medan, at ± 25 meters asl, from December 2023 to January 2024, using a Randomized Block Design with two factors and repeated 3 times. The first was the application of NPK 16:16:16 fertilizer (150; 200; 250 kg/ha). The second was biosaka solution concentration (0.67; 1.33; 2.00 ml/L). The application of NPK fertilizer had a real impact on plant height, leaves number, fresh shoots weight and harvest weight with the best NPK fertilizer dose of 150 kg/ha, but had no real effect on harvest index. The application of biosaka and interaction or both treatments have not real impact to all parameter’s.

PENGARUH PEMBERIAN PLANT GROWTH PROMOTING RHIZOBACTERIA (PGPR) PADA PERTUMBUHAN BIBIT STEK STEVIA (Stevia rebaudiana Bertoni)

Sweetleaf stevia (Stevia rebaudiana Bertoni) is one of the potential sugar-producing plants besides sugar cane which is widely used as a natural non-calorie sweetener. Propagation of stevia by shoot cuttings produces more uniform seedlings. Plant Growth Promoting Rhizobacteria (PGPR) contains a group of beneficial bacteria that live in the plant root ecosystem that can stimulate plant growth. This study aims to determine the effect of PGPR on the growth of stevia cuttings and the best concentration of PGPR on the growth of stevia cuttings. This study was conducted in February-May 2024 in Kolongan Atas II Village, Sonder District, Minahasa Regency, North Sulawesi Province. The study used a Completely Randomized Design (RAL), with 5 treatment levels, namely P0 = Control (Without PGPR), P1 = PGPR 10 ml/liter of water, P2 = PGPR 20 ml/liter of water, P3 = PGPR 30 ml/liter of water and P4 = PGPR 40 ml/liter of water. Each treatment was repeated 4 times.The results showed that the aplication of PGPR affected the growth of stevia cuttings. The best PGPR concentration for the growth of stevia cuttings was at a PGPR treatment concentration of 20 ml/liter of water. Keywords: plant growth promoting rhizobacteria, stevia

Rhizosphere Bacteria

Abstract The review is devoted to the analysis of modern literature data on rhizosphere bacteria and their role in the vital activity of plants. The structure of the rhizosphere is characterized, the role of plants as centers of formation of microbial communities is shown, data on the taxonomic affiliation of the main groups of microorganisms inhabiting the rhizosphere are presented. The associative relationships of rhizobacteria with a partner plant and the modern concept of a holobiont as a combination of a plant organism and associated microorganisms are considered. The role of rhizobacteria in the processes of azo fixation is discussed in detail. The mechanisms of direct stimulation of plant growth through the synthesis of phytohormones, improvement of phosphorus and nitrogen nutrition and increase in stress resistance, as well as indirect stimulation through antagonism with respect to phytopathogenic microorganisms are presented. The criteria for the selection of rhizobacteria for practical purposes are discussed.

Growth Promotion of Rice and Arabidopsis thaliana by Volatile Organic Compounds Produced by Endophytic Clonostachys Species.

Plant-endophytic fungi are widely distributed and highly diverse, with many of them capable of influencing plant growth and development, which is related to the production of volatile organic compounds (VOCs). While certain fungal VOCs have been found to stimulate plant growth, others exhibit inhibitory effects. Importantly, the impact of fungal VOCs extends beyond host plants to affect non-host plants as well. In this study, we isolated two plant-endophytic fungi, Clonostachys sp. CC1 and Clonostachys sp. CC2, from healthy rice roots. These strains were co-cultured with both rice and Arabidopsis thaliana. Our results demonstrated that both strains significantly enhanced the growth of both rice and A. thaliana. Specifically, they increased the length and biomass of rice and A. thaliana seedlings, as well as the chlorophyll content, while decreasing the H2O2 content in the leaves of both plants. The VOCs produced by these strains were analyzed using gas chromatography-mass spectrometry (GC-MS), which identified a total of 10 main ingredients. Among these compounds, 1-pentanol, ethylbenzene, and dimethyl phthalate inhibited the growth of rice while promoting the growth of A. thaliana, highlighting the variability in the effects of these compounds on different plant species and the complexity of plant-fungal interactions.

Exploring the Relationship Between Biochar Pore Structure and Microbial Community Composition in Promoting Tobacco Growth.

The potential benefits of biochar, a carbon-rich substance derived from biomass, for enhancing agricultural yield and soil health have drawn increasing interest. Nevertheless, owing to the lack of specialized studies, the role of its poly-spatial structure in the success of fostering plant growth remains unclear. This study aimed to assess the effects of various biochar pore shapes on tobacco growth and the underlying microbiological processes. Three pyrolysis temperatures (250 °C, 400 °C, and 550 °C) were used to produce biochar from tobacco stems, resulting in different pore structures (T3 > T2 > T1). We then used BET-specific surface area (BET), t.Plot micropore specific surface area (t.Plot), mesopore specific surface area (MSSA), specific pore volume (SPV), average pore size (AP), and mesopore pore volume (MPV) measurements to evaluate the effects of these biochars on tobacco growth and biomass accumulation, and microbial analyses were performed to investigate the underlying mechanisms. When applied to plants, biochar increased their growth compared to untreated controls. The most notable improvement in tobacco growth was observed in the biochar produced at 400 °C (T3), which possessed the largest and most advantageous pore structure among all treatments. Further studies demonstrated that biochars with greater specific surface areas (BET, t.Plot, and MSSA) positively altered the abundance of key microbial taxa (e.g., Stenotrophobacter, Ensifer, Claroideoglomus) and community composition, thereby encouraging plant development and biomass accumulation. Conversely, greater pore volumes (SPV, AP, and MPV) inhibited microbial activity and significantly affected growth and biomass accumulation. Structural equation modeling further demonstrated that the pore structure of biochar greatly affected plant growth by changing the relative abundance and community composition of soil microbes. Maximizing the benefits of biochar in stimulating plant growth and improving soil microbial communities depends on optimizing the material's pore structure, particularly by increasing the specific surface area. These findings will help expand the use of biochar in sustainable agriculture.

Unveiling the hidden world: How arbuscular mycorrhizal fungi and its regulated core fungi modify the composition and metabolism of soybean rhizosphere microbiome

BackgroundThe symbiosis between arbuscular mycorrhizal fungi (AMF) and plants often stimulates plant growth, increases agricultural yield, reduces costs, thereby providing significant economic benefits. AMF can also benefit plants through affecting the rhizosphere microbial community, but the underlying mechanisms remain unclear. Using Rhizophagus intraradices as a model AMF species, we assessed how AMF influences the bacterial composition and functional diversity through 16 S rRNA gene sequencing and non-targeted metabolomics analysis in the rhizosphere of aluminum-sensitive soybean that were inoculated with pathogenic fungus Nigrospora oryzae and phosphorus-solubilizing fungus Talaromyces verruculosus in an acidic soil.ResultsThe inoculation of R. intraradices, N. oryzae and T. verruculosus didn’t have a significant influence on the levels of soil C, N, and P, or various plant characteristics such as seed weight, crude fat and protein content. However, their inoculation affected the structure, function and nutrient dynamics of the resident bacterial community. The co-inoculation of T. verruculosus and R. intraradices increased the relative abundance of Pseudomonas psychrotolerans, which was capable of N-fixing and was related to cry-for-help theory (plants signal for beneficial microbes when under stress), within the rhizosphere. R. intraradices increased the expression of metabolic pathways associated with the synthesis of unsaturated fatty acids, which was known to enhance plant resistance under adverse environmental conditions. The inoculation of N. oryzae stimulated the stress response inside the soil environment by enriching the polyene macrolide antifungal antibiotic-producing bacterial genus Streptomyces in the root endosphere and upregulating two antibacterial activity metabolic pathways associated with steroid biosynthesis pathways in the rhizosphere. Although inoculation of pathogenic fungus N. oryzae enriched Bradyrhizobium and increased soil urease activity, it had no significant effects on biomass and N content of soybean. Lastly, the host niches exhibited differences in the composition of the bacterial community, with most N-fixing bacteria accumulating in the endosphere and Rhizobium vallis only detected in the endosphere.ConclusionsOur findings demonstrate that intricate interactions between AMF, associated core fungi, and the soybean root-associated ecological niches co-mediate the regulation of soybean growth, the dynamics of rhizosphere soil nutrients, and the composition, function, and metabolisms of the root-associated microbiome in an acidic soil.

Isolation and characterization of salt-stress-tolerant rhizosphere soil bacteria and their effects on plant growth-promoting properties

PGPR has a higher potential impact on agricultural crops. It enhances plant growth and development in a variety of adverse environmental conditions, including biotic and abiotic stresses. The PGPR is commercially vital since it is more efficient, safe for the environment, and beneficial to the economy. Nowadays, salt stress has an impact on the agricultural ecosystem. Salt-tolerant PGPR can directly stimulate plant growth and development by producing a variety of metabolites and phytohormones. The current study looked at the isolation of salt-tolerant bacterial species and their ability to stimulate plant development. Four bacterial species were chosen for their better salt stress tolerance (0–5%). They were identified by 16S rRNA sequencing: Solibacillus silvestris BR1, Peribacillus frigoritolerans BR2, Paenibacillus taichungensis CR1, and Solibacillus isronensis CR2. These strains were positive production of indole acetic acid with varying incubation periods (19.66 ± 1.528 to 646.111 ± 8.058 µg/mL), salt stress (ranging from 29.556 ± 1.171 to 147.8111 ± 2.086 µg/mL), phosphate solubilization (0.145 ± 0.011 to 0.921 ± 0.007 µg/mL), ammonium production (0.299 ± 0.047 to 1.202 ± 0.142 µg/mL), HCN production (0.308 ± 0.051 to 4.269 ± 0.069 µg/mL), and siderophore production (0.190 ± 0.064 to 1.543 ± 0.108 µg/mL) for control strains were used without salt stress. The production level was expressed using a standard curve containing various standards.

Harnessing the power of rhizosphere bacteria for pollution remediation: strategies, mechanisms, and environmental impact: A review

This review explores into the sizeable potential of rhizosphere bacteria as effective mediators in the pollution remediation. These rhizosphere bacteria are primarily found in the soil surrounding plant roots, and they have an extremely strong ability to remove a wide range of toxins from the environment. This is attuned with the idea of phytoremediation, which is the use of plants to clean adulterated soil or water. In addition to vigorous participation in bioremediation processes, their diverse activities include stimulating plant growth and serving as biocontrol agents against plant diseases. Their ability to gather, change, and restrain pollutants is one of their main advantages, especially when used in combination with phytoremediation techniques. To fully utilize these microorganisms, it is essential to understand the various bacterial strains and their complex biological pathways that influence their behavior. The diversity and richness of rhizosphere bacterial populations, significantly affected by different plant species and environmental factors, is a crucial area that requires further study. Grasping this heterogeneity is essential for adapting phytoremediation strategies to particular contamination situations and exploiting their effectiveness. Rhizosphere microorganisms present a feasible path towards a more supportable and clean future. This might potentially make a big contribution to environmental restoration efforts in a world that is always changing.

Synthesis and characterization of novel dithiocarbamic thioanhydrides and their application for plant growth stimulant and phytotoxic activity

In this study, nineteen thioanhydrides were synthesized from the S-acylation reaction of sodium dithiocarbamates with various acyl chlorides in chloroform at room temperature. The synthesized thioanhydrides were evaluated for their growth-stimulating and phytotoxic activities. Benzoic (1a), 4-methoxy- (1b), 4-chloro- (1c), 2-bromo- (1e), 4-fluoro- (1f.) and 4-nitrobenzoic 1H-1,2,4-triazole-1-carbothioic thioanhydrides (1 g) showed moderate to excellent growth-stimulating activity, along with this (1c) exhibited excellent phytotoxic activity, 2,4-dichlorobenzoic 1H-1,2,4-triazole-1-carbothioic thioanhydride (1d) and 2,4-dichlorobenzoic pyrrolidine-1-carbothioic thioanhydride (2b) demonstrated inhibiting and moderate phytotoxic activities. Thioanhydrides (1a-c, 1f., 1 g) exhibited excellent germination energy and germination capacity of wheat seeds: 1a 82 and 90%, 1c 80 and 84%, 1 g 82 and 90% (0.01 mg/ml); 1b, 1 g 78 and 94%, 1c 78 and 90%, 1f. 80 and 94% (0.1 mg/ml). Thioanhydride (1e) showed moderate activity, germination energy and germination capacity were 72 and 76% (0.1 mg/ml), 78 and 84% (0.01 mg/ml). Thioanhydride (1d) demonstrated activity as a growth inhibitor with germination energy, and germination capacity 54 and 58% (0.1 mg/ml), 44 and 42% (0.01 mg/ml). Thioanhydride (1c) exhibited excellent phytotoxic activity analogically to herbicide 2,4-D only on lettuce seeds. Compounds (1d and 2b) were moderately active, inhibiting the growth of lettuce and bent grass seedlings.

Associations of Arbuscular Mycorrhizal Fungi (AMF) for Enhancements in Soil Fertility and Promotion of Plant Growth: A Review

Arbuscular Mycorrhizal Fungi are used for soil fertility enhancements and stimulating plant growth in which they association with other organisms like terrestrial plants. Mycorrhizas create an association between fungi and the roots of plants. Therefore, the review was made to point out important fungal species involved in fungal plant interaction and their major roles in agriculture as well as ecosystem. 80% of plants form associations with mycorrhizal fungi. The fungal are used to use their different organs like chain, arbuscular, vesicle, supportive cells and spore to interact with the other plant/ plat’s organ. The mycorrhizal fungi can be categorized into two principal classifications based on their anatomical interactions with the roots of host plants. Arbuscular Mycorrhizal and Ectomycorrhizal fungi utilize two distinct strategies for nutrient acquisition. The main categories of vesicular arbuscular mycorrhizal associations are linear or coiling and of ectomycorrhizal associations are epidermal or cortical. The rhizospheric and endophytic microbes promote plant growth as inoculated with crop. AM fungi as an obligate symbiont share a distinct feature called arbuscules as a site of nutrient exchanges between host and fungi. Arbuscules developed between cell wall and plasma membrane of root cortical cells and differentiated from plant plasma membrane by periarbuscular membrane. Arbuscular mycorrhizal fungi (AMF) play an indispensable role in augmenting plant nutrient acquisition, enhancing plant resilience and tolerance to various environmental stresses, improving soil fertility and structure, and providing numerous beneficial effects. AMF engage in interactions with other soil microorganisms, such as plant growth-promoting rhizobacteria, resulting in a synergistic effect that promotes plant growth and offers protection against pathogens associated with Rhizobia. Both AMF and Rhizobia utilize the same signaling pathways, which facilitate their association with host plants and enable nitrogen fixation within the soil ecosystem. A positive relationship has been established between AMF colonization and the diversity of soil microbial communities. Nitrogen-fixing rhizobia, mycorrhizal fungi, and root nodule symbioses typically exhibit synergistic interactions concerning infection rates and their effects on mineral nutrition and plant growth, thereby significantly enhancing the status of soil fertility, particularly with respect to soil quality characteristics.