Search Results (6)

This study addresses the challenge of finding novel ways to solubilize phosphorus and zinc for agricultural purposes. The aim was to isolate PSMs (phosphorous-solubilizing microbes) and ZnSMs (zinc-solubilizing microbes) from different environments (e.g., soil amendments, land uses, and crop rotation systems) and evaluate their ability to solubilize different insoluble P sources (e.g., β-tricalcium phosphate (β-TCP), calcium-phytate (CaP), and rock phosphate (RP)) and Zn sources (e.g., zinc carbonate (ZnC), zinc oxide (ZnO), and zinc phosphate (ZnP)). Here, 25 isolates capable of solubilizing either P or Zn sources were isolated and classified by species using 16S rRNA and ITS-region sequencing. Notably, Aspergillus awamori, Fusarium circinatum, Fusarium longifundum, and Mucor circinelloides, isolated from cultivated soils and soil amendments, emerged as the most efficient PSMs and ZnSMs. Mucor circinelloides exhibited the highest solubilization ability for broths containing β-TCP, CaP, RP, ZnO, and ZnP, with log2-fold changes of 3.7, 1.8, 8.9, 7.8, and 2.4, respectively, compared to the control. For ZnC and ZnO, Aspergillus awamori displayed the highest Zn solubilization, with a 2.1 and 3.0 log2-fold change. The study highlights the potential of these strains as biofertilizers and underscores the role of Mucor and Fusarium genera in zinc solubilization. Full article

Soil macro- and micronutrient nutrient availability and their uptake by plants are critically reliant upon an active presence of the soil microbiome. This study investigated the effect of two locally sourced bio-inocula, local effective microorganisms (LEMs) and false-local effective microorganisms (F-LEMs), on plant available nitrogen (N) and phosphorus (P), and the uptake of calcium (Ca), magnesium (Mg), potassium (K), and zinc (Zn) content in edamame (Glycine max. L.) and pumpkin (Cucurbita maxima) grown in a randomized complete block design with four reps, summer 2017 and 2018, respectively. LEM plots showed greater plant-available N during the first week (edamame season) and fourth week (pumpkin season) after treatment applications. During the pumpkin season, post-treatment plant-available P was greater in both summers in LEM plots. Edamame bean had 19%, 3%, 5%, and 16% greater Ca, Mg, K, and Zn content in LEM plots compared to the Control, respectively. The concentration of K in pumpkin pulp at harvest was 31% higher in LEMs than in F-LEMs, while Mg concentration was 42% higher. Pumpkin pulp and seeds also had 27% and 34% greater Ca and Zn concentrations compared to the Control. Our study suggests that LEMs were effective in solubilizing macro- and micronutrients, which led to increased plant uptake. Full article

Plant growth-promoting microorganisms (PGPM) benefit plant health by enhancing plant nutrient-use efficiency and protecting plants against biotic and abiotic stresses. This study aimed to isolate and characterize autochthonous PGPM from important agri-food crops and nonagricultural plants to formulate biofertilizers. Native microorganisms were isolated and evaluated for PGP traits (K, P, and Zn solubilization, N₂-fixation, NH₃-, IAA and siderophore production, and antifungal activity against Fusarium oxysporum). Isolates were tested on radish and broccoli seedlings, evaluating 19 individual isolates and 12 microbial consortia. Potential bacteria were identified through DNA sequencing. In total, 798 bacteria and 209 fungi were isolated. Isolates showed higher mineral solubilization activity than other mechanisms; 399 bacteria and 156 fungi presented mineral solubilization. Bacteria were relevant for nitrogen fixation, siderophore, IAA (29–176 mg/L), and ammonia production, while fungi for Fusarium growth inhibition (40–69%). Twenty-four bacteria and eighteen fungi were selected for their PGP traits. Bacteria had significantly (ANOVA, p < 0.05) better effects on plants than fungi; treatments improved plant height (23.06–51.32%), leaf diameter (25.43–82.91%), and fresh weight (54.18–85.45%) in both crops. Most potential species belonged to Pseudomonas, Pantoea, Serratia, and Rahnella genera. This work validated a high-throughput approach to screening hundreds of rhizospheric microorganisms with PGP potential isolated from rhizospheric samples. Full article

Multidrug-resistant microorganisms have become a significant public health threat, and traditional antibiotics are becoming ineffective. Photodynamic therapy (PDT) is a promising alternative that utilizes photosensitizers and light to produce Reactive Oxygen Species (ROS) that can kill microorganisms. Zinc phthalocyanine (ZnPc) is a promising photosensitizer due to its strong affinity for encapsulation in nanoemulsions and its antimicrobial properties. In this study, nanoemulsion was prepared using Miglyol 812N, a surfactant, and distilled water to dissolve hydrophobic drugs such as ZnPc. The nanoemulsion was characterized by its particle size, polydispersity index, Transmission Electron Microscope and Zeta potential, and the results showed that it was an efficient nanocarrier system that facilitated the solubilization of hydrophobic drugs in water. The use of ZnPc encapsulated in the nanoemulsion produced through the spontaneous emulsification method resulted in a significant reduction in cell survival percentages of gram-positive Staphylococcus aureus and gram-negative Escherichia coli by 85% and 75%, respectively. This may be attributed to the more complex cell membrane structure of E. coli compared to S. aureus. This demonstrates the potential of nanoemulsion-based PDT as an effective alternative to traditional antibiotics for treating multidrug-resistant microorganisms. Full article

This review presents a comprehensive and systematic study of the field of bacterial plant biostimulants and considers the fundamental and innovative principles underlying this technology. Plant biostimulants are an important tool for modern agriculture as part of an integrated crop management (ICM) system, helping make agriculture more sustainable and resilient. Plant biostimulants contain substance(s) and/or microorganisms whose function when applied to plants or the rhizosphere is to stimulate natural processes to enhance plant nutrient uptake, nutrient use efficiency, tolerance to abiotic stress, biocontrol, and crop quality. The use of plant biostimulants has gained substantial and significant heed worldwide as an environmentally friendly alternative to sustainable agricultural production. At present, there is an increasing curiosity in industry and researchers about microbial biostimulants, especially bacterial plant biostimulants (BPBs), to improve crop growth and productivity. The BPBs that are based on PGPR (plant growth-promoting rhizobacteria) play plausible roles to promote/stimulate crop plant growth through several mechanisms that include (i) nutrient acquisition by nitrogen (N₂) fixation and solubilization of insoluble minerals (P, K, Zn), organic acids and siderophores; (ii) antimicrobial metabolites and various lytic enzymes; (iii) the action of growth regulators and stress-responsive/induced phytohormones; (iv) ameliorating abiotic stress such as drought, high soil salinity, extreme temperatures, oxidative stress, and heavy metals by using different modes of action; and (v) plant defense induction modes. Presented here is a brief review emphasizing the applicability of BPBs as an innovative exertion to fulfill the current food crisis. Full article

Unavailability of balanced nutrients in nutrient-deficient soils is the key reason in reduced yields of spring maize. After application to soil, most of the phosphorus (80–90%) is lost in the environment because of runoff losses and chemically bonding. So, this makes the phosphorus unavailable for plant use. However, soil microorganisms may provide a biological rescue system which is able to solubilize the soil-bound phosphorus (p). Keeping this in view, the present study is designed to meet the following objectives; (1) to improve physico-chemical properties of soil (e.g., soil water retention, soil enzyme activities), and (2) to improve growth and yield of spring maize (cv. Hybrid YSM-112) through the inoculation of phosphorus solubilization bacteria (PSB). A pot experiment was carried out with the following treatments; T1: control (uninoculated control, CT), T2: inoculation with PSB (Enterobacter sakazakii J129), T3: recommend level of NPK fertilizers (RNPK), T4: PSB + RNPK fertilizers, T5: rock phosphate (RP), T6: PSB + RP. Results showed that the addition of PSB together with RNPK improved the yield and yield-related characteristics of spring maize grown in sandy soil. Moreover, it also enhanced dry mater characteristics and maize grain quality. Soil fertility in the context of P-solubilization, soil organic acids, soil organic matter, enzyme activities, PSB colony, and rhizosphere moisture contents were significantly improved with PSB inoculation together with recommended dose of NPK fertilizers (RNPK) compared to PSB alone, rock phosphate (RP) alone, or PSB together with rock phosphate and control treatment. Maize digestibility attributes such as DM, CP, CF, EE (by 35%, 20%, 33%, and 28% respectively) and grain quality such as NPK, Mg, Ca, Fe, Mn, Cu, and Zn (by 88%, 92%, 71%, 68%, 78%, 90%, 83, 69%, 92%, 48%, and 90% respectively) were improved compared to control. In conclusion, improvement in maize crop yield and soil characteristics are more prominent and significant when RNPK is supplemented and inoculated. The present study suggests that PSB, together with RNPK, would improve the maize plant growth and soil fertility in sandy soil. Full article