Co-inoculation of endophytic bacteria enhances hydroponic wheat performance and zinc biofortification through root exudates modulation

Synergistic Effects of Vitreous Amendment and Mycorrhizal Fungi on Durum Wheat Water Stress Tolerance

Bacillus from the Brazilian Caatinga biome enhances maize productivity and agronomic performance under rainfed conditions across multi-location field trials

Drought stress is among the most critical limitations to maize productivity, particularly under rainfed conditions. In this study, we explored the Brazilian Caatinga biome as a source of drought adapted plant growth-promoting bacteria and evaluated their potential to mitigate drought effects in maize (Zea mays L.). A total of 414 thermo-tolerant bacterial strains were isolated from soil, of which 28 Bacillus strains were able to grow under low water activity. These strains exhibited multiple plant growth-promoting traits in vitro, including exopolysaccharide production, biofilm formation, siderophore production, indole-3-acetic acid synthesis, putative nitrogen fixation, and phosphate solubilization. Twelve selected strains significantly improved root morphology, relative chlorophyll content (SPAD units), and biomass accumulation in maize seedlings under osmotic stress induced by polyethylene glycol. Notably, strain 1A11 showed the most consistent effects, promoting root growth and biomass accumulation under both stressed and non-stressed conditions, indicating constitutive growth promotion across environments, whereas other strains showed stronger responses under stress. This stability across environments strengthens its agronomic value, particularly in regions characterized by high rainfall variability. Genome sequencing of five elite strains (1A11, 5D5, 6E9, 1H10, and 2E7) identified conserved gene clusters associated with exopolysaccharide production, indole-3-acetic acid synthesis, phosphate metabolism, iron acquisition (siderophore synthesis), synthesis of volatile compounds, motility, chemotaxis, and general responses to osmotic and oxidative stress. Multi-location field trials conducted across five locations in Brazil, under rainfed conditions, indicate that strains 1A11 (Bacillus subtilis), 5D5, and 6E9 (Bacillus velezensis) consistently increased grain yield compared to the non-inoculated control and performed similarly to or better than a commercial inoculant. Mean productivity gains with the strain 1A11 reached up to 39% relative to the non-inoculated treatment across environments. These results indicate that Bacillus strains isolated from semi-arid soils were able to convert multifunctional potential into measurable agronomic gains under field conditions, demonstrating their potential as bioinoculants to enhance maize resilience under water-limited agricultural systems.

Combined microbial inoculation improves plant growth, nutrient acquisition, and soil biological functioning in Opuntia ficus-indica under water deficit

It is demonstrated that combined PGPR and AMF inoculation represents an effective and sustainable strategy to enhance soil biological functioning, nutrient cycling, and drought tolerance of O. ficus-indica in water limited environments.

Endophytic Aspergillus fumigatus modulates growth, oxidative stress, and cadmium accumulation in okra under salinity and heavy-metal stress

It is shown that endophytic fungi have the potential to enhance plants’ resilience and provide a promising controlled-environment approach to enhance crop productivity in metal- and salt-contaminated soils.

Exploring the Influence of Biofertilizer on Early Plant Growth in A Hydroponic System

Hydroponics provides an efficient alternative to soil-based cultivation by conserving water, minimizing soil-borne diseases, and addressing land constraints. Coco peat serves as an effective growth medium due to its favorable aeration and moisture retention properties, while plant growth-promoting bacteria (PGPB) such as Phosphate-Solubilizing Bacteria (PSB) and Azotobacter are known to enhance nutrient availability through biological mechanisms. The present study investigates the influence of coco peat enriched with PGPB on early-stage plant growth under hydroponic conditions. PSB and Azotobacter were applied individually and as a consortium using seed coat and spray methods to evaluate their effects during the initial stages of plant development. PSB facilitates the solubilization of inorganic phosphates, whereas Azotobacter contributes to nitrogen fixation, potentially supporting early seedling establishment. The experiment was conducted in a controlled hydroponic setup over a short duration, and growth-related physical parameters indicative of early plant response were monitored. The results revealed that the consortium treatment exhibited enhanced early-stage growth parameters compared to individual applications across both treatment methods. The observed improvement in seedling performance suggests an interaction between PSB and Azotobacter during the initial growth phase. As this study represents a preliminary, short-term assessment, conclusions regarding long-term plant performance, crop yield, or reduction in chemical fertilizer dependency would require further experimentation and confirmation of results. However, the findings provide foundational insights into microbial-assisted early growth responses in hydroponic systems and highlight the need for extended-duration and field-scale studies to evaluate long-term agronomic implications.

Integrative evaluation of symbiotic performance and biomass allocation in rhizobial inoculated cowpea under contrasting soil microbial conditions

Reliable evaluation of rhizobial inoculant performance requires integrative assessment of nodulation and biomass responses under contrasting soil microbial environments. A controlled pot experiment was conducted to evaluate cowpea (Vigna unguiculata L. Walp.) responses to inoculation with Sinorhizobium fredii, Bradyrhizobium japonicum, mineral nitrogen (urea), and a non-inoculated control under heat-treated and unsterilized sandy loam soils. Treatments were arranged in a completely randomised design with three replicates and monitored up to 10 weeks after planting (WAP). Nodulation, vegetative growth, shoot biomass, and root biomass were assessed at 2, 4, 6, 8, and 10 WAP. Integrative indices, including nodulation biomass efficiency ratio (NBER), biomass allocation ratio (BAR), and symbiotic advantage index (SAI), were calculated at 10 WAP, and Pearson correlation analysis was performed. Nodulation differed significantly among treatments under both soil conditions (P ≤ 0.001). In heat-treated soil, S. fredii produced 45.33 nodules plant−1 compared with 27.00 nodules plant−1 under B. japonicum, while non-inoculated plants showed limited nodulation (5.00 nodules plant−1), indicating residual indigenous rhizobial influence. Under unsterilized soil, nodulation increased to 74.00 and 46.00 nodules plant−1 under S. fredii and B. japonicum, respectively. S. fredii also produced the highest shoot (5.70 g plant−1) and root biomass (2.70–2.80 g plant−1). Integrative indices significantly differentiated treatment performance, confirming S. fredii as the most effective inoculant and demonstrating the value of combined nodulation-biomass assessment for evaluating rhizobial effectiveness. Rhizobial inoculation significantly enhanced cowpea nodulation and biomass production. Sinorhizobium fredii exhibited superior nodulation and symbiotic effectiveness. Soil microbial conditions strongly influenced nodulation establishment and treatment response. Mineral nitrogen promoted vegetative growth but suppressed nodulation. Integrative indices (NBER, BAR and SAI) improved discrimination of rhizobial effectiveness. Rhizobial inoculation significantly enhanced cowpea nodulation and biomass production. Sinorhizobium fredii exhibited superior nodulation and symbiotic effectiveness. Soil microbial conditions strongly influenced nodulation establishment and treatment response. Mineral nitrogen promoted vegetative growth but suppressed nodulation. Integrative indices (NBER, BAR and SAI) improved discrimination of rhizobial effectiveness.