Search Results (1,527)

Phosphorus (P) is one of the main limiting factors for sugarcane establishment and longevity in tropical soils, requiring biotechnological strategies to improve fertilizer use efficiency. This study evaluated the effects of inoculation with Bacillus velezensis UFV 3918, alone or combined with reduced monoammonium phosphate (MAP) doses, on the morphological, nutritional, and root nutrient uptake responses of sugarcane grown in a dystrophic Red Latosol under greenhouse conditions. The experiment was conducted in a completely randomized design with six treatments and four replicates: absolute control (AC, without MAP), commercial control (CC, recommended MAP dose), B. velezensis alone (Bv), and Bv combined with 1/3, 2/3, or the full recommended MAP dose. Plant growth responses varied across treatments and stages, with Bv promoting greater leaf area than the CC at 120 and 180 DAP, whereas Bv + 1/3 MAP maintained leaf area comparable to the CC throughout the evaluation period. Principal component analysis (PCA) revealed a clear separation among treatments, with Bv exhibiting the most distinct plant response, primarily associated with greater stalk diameter, root and stalk biomass, higher concentrations of potassium and phosphorus in stalks, sulfur and magnesium in roots, and greater boron-use efficiency. Bv + 1/3 MAP displayed an intermediate multivariate profile, mainly associated with phosphorus uptake per unit root length and nutritional attributes related to phosphorus acquisition under reduced fertilizer supply. Correlation analysis further revealed strong positive associations among growth-related traits, biomass accumulation, and phosphorus-related variables, indicating a close relationship between P acquisition and plant responses to bacterial inoculation. Overall, inoculation with B. velezensis UFV 3918 improved early sugarcane growth and nutrient acquisition, and its combination with 1/3 of the recommended MAP rate maintained plant performance. These findings indicate the potential for reducing mineral P inputs during early sugarcane establishment; however, long-term field trials are required to determine whether these responses can be sustained throughout the crop cycle and under commercial production conditions. Full article

Plant growth-promoting bacteria (PGPB) are increasingly deployed as biofertilizers, yet the link between an inoculant’s genomic potential and its realized effect on the plant is rarely assessed within an integrative framework that jointly captures the rhizosphere microbiome, plant phenotype, and strain genome. Two Bacillus strains—B. halotolerans 1453 and B. pumilus 630—were applied to wheat and soybean in a factorial pot experiment (2 strains × 2 application methods × 3 frequencies + control, 3–4 replicates). Rhizosphere samples (n = 67 after filtering) were profiled by 16S rRNA sequencing with PICRUSt2 functional prediction and compositional validation (Aitchison PERMANOVA, ALDEx2, ANCOM-BC2). The PGPB gene repertoire was characterized by genome mining (481 marker genes, 14 categories). Wheat phenotype (six traits) and soybean height were analyzed with models appropriate for count data (Negative Binomial and binomial GLMs) for treatment-vs.-control comparisons, and with factorial ANOVA for decomposition into main effects and interactions. Crop identity was the dominant factor shaping both microbiome structure and function (PERMANOVA R² = 14.7% taxonomically and R² = 7.8% functionally, both p < 0.001), with biologically meaningful taxonomic differences between wheat and soybean; strain, application count and method had no significant effect on community composition (R² < 4% each), and co-occurrence networks showed no reliable differences between crops once read depth and sample size were controlled for. Despite this neutrality at the microbiome level, inoculation significantly increased wheat spike count (NB-GLM, all 12 treatments vs. control, padj 0.0002–0.031), ear weight, and stem count, with application count the strongest source of variability and a pronounced strain × application count. Strain 1453 outperformed 630 in spike count (+23.1%, p = 0.012) and ear weight (+20.4%, p = 0.023); we hypothesize that this may be related to its more complete DNRA pathway (narGHI + nirB-nirD) and biocontrol genes (bacE, srfAA). Strain 630 produced a less pronounced effect than strain 1453 but was subject to smaller fluctuations across replicates (CV ≈ 16–21% vs. ≈24–26% for 1453), which may reflect better resilience to environmental fluctuations, possibly due to its confirmed rsbV/rsbW stress-tolerance regulon. Rhizosphere microbiome composition differed clearly by crop (wheat vs. soybean) but showed no detectable response to strain, application method, or application count. Despite this lack of a microbiome signal, inoculation significantly increased wheat spike count and ear weight, with the magnitude and stability of this effect differing by strain. We hypothesize that this strain-dependent difference relates to underlying genomic differences—particularly in nitrogen metabolism (DNRA pathway) and stress-tolerance genes—though this link has not been tested directly and remains a hypothesis for future work. Full article

Background: The monocarpic woody bamboo Chimonobambusa opienensis flowers synchronously and undergoes post-flowering senescence, imposing high nutritional demands during reproduction. Field investigations have documented increases in rhizosphere nutrients during bamboo blooming, but the underlying metabolic–microbial mechanisms remain unclear. Methods: Eight biological replicates of flowering (FD) and non-flowering (NF) C. opienensis across two locations were used to investigate differences in rhizosphere metabolites, microbiota, functional genes, and soil nutrient stoichiometry. A total of 2196 metabolites were identified, including 108 specific to FD and 63 specific to NF. Flowering was associated with metabolic reprogramming: flavonoids (2′,5,6-trimethoxyflavone) and antioxidant metabolites increased, whereas growth-promoting phytohormones and structural maintenance metabolites decreased. This metabolic transition was accompanied by substantial functional reorganization of the rhizosphere microbiome. Ammonia-oxidizing archaea (AOA) and nitrite-oxidizing bacteria (NOB), functional guilds associated with nitrification, were selectively enriched in FD rhizospheres, suggesting a shift from carbon-cycle predominance toward nitrogen-activation potential. NF rhizospheres harbored a microbial consortium associated with decomposition and methanogenesis of complex organic matter. In FD rhizospheres, nitrogen and phosphorus contents were significantly higher (p < 0.05). Correlation analyses revealed strong associations among root metabolites, functional microbial guilds, and soil nutrient pools. Conclusions: The rhizosphere metabolite–microbe–nutrient axis is associated with the increased nutrient demands of flowering and may support reproductive success in monocarpic bamboos. A putative “metabolic signals–microbial functions–nutrient supply” interaction network is identified in the flowering rhizosphere, advancing our understanding of perennial clonal plant–microbe interactions during reproductive transitions. Full article

Acidic soils are widespread in global agroforestry systems and severely constrain crop production through proton stress, aluminum/manganese phytotoxicity, phosphorus fixation, and rhizosphere microbiome reassembly. Rhizosphere diazotrophs can theoretically contribute to plant nitrogen (N) nutrition and stress adaptation. However, their N-fixation efficiency and growth-promoting effects in acidic soils are often highly unstable, limiting the predictability of field applications. This narrative mechanistic review synthesizes and critically interprets evidence on the physicochemical filters governing diazotroph survival in acidic soils, nitrogenase regulation, root-exudate-mediated recruitment, multi-guild microbial interactions, and the conditional design of synthetic microbial communities (SynComs) and inoculant formulations. We further discuss the potential complementary roles of phosphate-solubilizing bacteria (PSB) and arbuscular mycorrhizal fungi (AMF) and propose minimum reporting standards to improve field translatability. The synthesis indicates that effective diazotroph-mediated crop promotion depends on pH buffering, metal detoxification, carbon supply, phosphorus availability, host compatibility, and native microbiome receptivity. The proposed evidence-chain and microbiome-compatibility framework is a conceptual guide for evaluating these linked conditions rather than an empirically validated predictive model. Full article

Plant growth-promoting bacteria (PGPB) enhance plant development through mechanisms such as the production of indole-3-acetic acid (IAA). However, endophytic bacteria associated with aquatic plants, particularly watermeal (Wolffia spp.), remain poorly explored. This study investigated the potential of bacterially derived crude IAA extract for enhancing watermeal growth and accumulation of secondary metabolites in watermeal. This study isolated and screened endophytic bacteria from watermeal for IAA production, identifying Klebsiella variicola W1/6 as the most efficient producer. Optimization using response surface methodology (RSM) revealed optimal conditions at pH 5.84, 5 days of incubation, and 10.63% (v/v) inoculum size. Crude IAA extract significantly enhanced watermeal growth under both laboratory and greenhouse conditions. Notably, the combination of 0.5 ppm crude IAA extract with 50% chemical fertilizer produced growth comparable to that of the full fertilizer treatment, indicating reduced fertilizer requirement. These findings highlight the potential of bacterially derived IAA from K. variicola W1/6 as a microbial biostimulant for sustainable aquatic plant cultivation. Full article

Aquaponics combines aquaculture and hydroponics, offering an integrated and sustainable food production system. This study investigated the probiotic properties, plant growth-promoting (PGP) activity, and nitrifying capacity of twelve lactic acid bacteria (LAB) strains isolated from an aquaculture farm environment on the Ivory Coast for their potential application in aquaponic systems. All isolates demonstrated antagonistic activity against key pathogenic indicator strains, except Vibrio cholerae, and displayed varying levels of surface hydrophobicity (5.50 ± 0.70% to 22.83 ± 1.17%) and auto-aggregation (32.50 ± 0.08% to 52.89 ± 0.39%) after 24 h. Antioxidant activity was significantly higher in cell-free supernatants (~71–79%) than in intact cells (~30–33%). Bile salt tolerance (0.3%, 4 h) ranged from 2.13 ± 0.76% to 40.87 ± 2.12%, and survival under pH 1.5 with pepsin for 3 h varied from 4.84 ± 0.26% to 53.98 ± 13.28%. All isolates produced lactic, acetic, citric, malic, and propionic acid and exhibited amylase and cellulase activity; none showed hemolytic activity. Only LAB 11 produced indole-3-acetic acid (17.72 ± 0.06 μg/mL), siderophores, and phosphate-solubilization activity for PGP traits, and this group significantly enhanced maize seed germination (86.66 ± 5.77%) and radicle length (7.00 ± 0.52 mm) compared to the control (63.33 ± 32.14% and 4.94 ± 1.52 mm), respectively. LAB 1 and LAB 10 demonstrated the highest ammonia-oxidizing capacity in vitro and in trout pond water. LAB 1, LAB 10, and LAB 11 were confirmed by whole genome sequencing analysis to be Enterococcus faecalis strains with a favorable-safety genomic profile and probiotic characteristics. These three strains therefore represent promising candidates for consortium-based applications in aquaponics systems. Full article

Crop production is continually exposed to a wide range of abiotic stresses that negatively affect growth and yield, posing a severe threat to global food security. Plant growth-promoting bacteria (PGPB) promote nutrient assimilation, activate antioxidant enzymes, and stimulate phytohormone production to mitigate abiotic stress. However, the effective application of PGPB in the field depends on host colonization, soil specificity, and susceptibility to competitive microbial communities. Recently, non-thermal plasma (NTP) has emerged as a revolutionary tool for sustainable agriculture, making it a priority to develop efficient, low-cost, and eco-friendly strategies to enhance seed vitality and manage abiotic stress. Plasma-generated reactive oxygen and nitrogen species (RONS) have been shown to mediate intracellular redox homeostasis and the antioxidant defense signaling network. Furthermore, plasma stimulates MAPK cascades and stress-responsive genes such as LEA1, SnRK2, P5C, and the SOS pathway, ionic balance, and membrane stability, ultimately supporting plant stress adaptation to drought, salinity, and heavy metals. Plasma-induced RONS signaling activates PGPB functional traits such as root colonization, biofilm formation, nutrient mobilization, and plant growth-promoting activities. However, the molecular mechanisms underlying NTP-PGPB microbial multiple stress adaptation and the long-term ecological stability and biosafety of microbial communities remain inadequately resolved. Consequently, future integration of multi-omics approaches, synthetic microbial communities, and field-scale validation is required to explore the mechanistic advances of plasma-modulated microbiome interactions to enable agricultural applications. Full article

Polygonatum cyrtonema Hua polysaccharides (PCPs) are bioactive components with antioxidant and immunomodulatory properties. However, whether the polysaccharides derived from elder Polygonatum cyrtonema exhibit superior health benefits remains unclear. This study systematically compared the in vitro fermentation characteristics, gut microbiota-modulating effects, and short-chain fatty acid (SCFA) production of PCPs extracted from three-year-old (TPP), five-year-old (FPP), and eight-year-old (EPP) plants using a human fecal fermentation model. The fermentation dynamics were evaluated by monitoring pH, OD₆₀₀, and the consumption of total and reducing sugars, while the structural degradation and compositional differences in PCPs were tracked via molecular weight distribution and monosaccharide composition analysis. The results showed that all three PCPs were degraded and utilized by gut microbiota, accompanied by decreased pH, increased OD₆₀₀, and enhanced antioxidant activities. High-throughput 16S rDNA sequencing revealed that, at the phylum level, all PCPs increased the Firmicutes/Bacteroidetes ratio. At the genus level, they reduced the abundance of harmful bacteria such as Sutterella and increased beneficial bacteria including Bifidobacterium and Megasphaera. Furthermore, gas chromatography (GC) analysis demonstrated that, compared with FPP, TPP and EPP significantly promoted the production of SCFAs. In summary, this study indicates that the in vitro fermentation characteristics and prebiotic properties of PCPs vary with growth years, and a comprehensive evaluation suggests that three-year-old Polygonatum cyrtonema Hua represents a promising raw material for the development of functional foods. Full article

Salinity stress is one of the major stressors that limits yield potential in field crops. Salinity-led imbalances in ionic and water potential, as well as oxidative damage, impair photosynthesis. Plant-growth-promoting rhizobacteria (PGPRs) have been demonstrated to mitigate salinity-stress-induced damage through various mechanisms such as biofilm and exopolysaccharide production, modulation of plant root architecture or molecular signaling involving modulation of sodium/potassium efflux transporters. PGPRs are known to induce biosynthesis and signaling of various phytohormones in plants. PGPR-derived phytohormones can in turn regulate molecular signaling involved in maintaining ion fluxes, preventing salinity-induced senescence, and reinforcing plant root architecture, thereby maintaining plant growth and development under saline conditions. In this review, we provide comprehensive advances on how PGPRs modulate and integrate biosynthesis and/or signaling of various phytohormones, such as auxins, cytokinins, gibberellin, ethylene, abscisic acid, salicylic acid, jasmonates, brassinosteroids and strigolactones, to reshape plant architecture, physiological and biochemical responses in plants under salinity. We integrate molecular evidence with morpho-physiological studies and propose a phytohormone-centric framework to select strains that optimize growth, ion homeostasis and plant stress resilience under salinity. Full article

Duckweed-associated plant growth-promoting bacteria have attracted attention for their potential to enhance duckweed biomass production. However, the mechanisms underlying isolate-specific growth promotion are unclear. This study compared the effects of two duckweed-associated bacterial isolates, Terrimicrobium sp. PS02 and Aeromicrobium sp. PS05, on the growth, biomass composition, colonization behavior, and transcriptomic responses of Spirodela polyrhiza. Biomass composition and transcriptome analyses were performed to characterize the host responses. Both isolates enhanced duckweed biomass; PS02 increased it 1.2-fold, whereas PS05 induced a significant 1.4-fold increase compared to the uninoculated control. PS05 established bacterial populations approximately one order of magnitude higher than those of PS02 and formed dense extracellular polymeric substance-mediated microcolonies on the surface. Transcriptome analysis revealed that PS05 induced 1108 differentially expressed genes, compared with 454 in PS02, indicating greater host transcriptomic reprogramming. Functional enrichment of transcriptome responses showed that PS05 preferentially regulates carbohydrate biosynthesis, central carbon metabolism, and starch biosynthesis, significantly enhancing starch accumulation and turion formation without reducing protein or photosynthetic pigment content. This study provides evidence linking bacterial colonization, host transcriptomic regulation, carbon allocation, and biomass production in duckweed, offering a basis for engineering high-performance duckweed–microbiome systems for sustainable biomass production. Full article

The degradation of Calcisols in the arid regions of Central Asia constrains sustainable agricultural production because of low organic matter content, poor aggregate stability, nutrient limitations, and increasing climatic stress. This study evaluated a rhizosphere engineering approach based on the native plant growth-promoting bacterium Pseudomonas veronii Ps-S/Sh-1503/2022 for the rehabilitation of degraded Calcisols. Four-year field experiments (2022–2025) using Sorghum bicolor assessed plant growth, rhizosphere microbial indicators, physiological responses, pathogen suppression, crop productivity, and implementation feasibility through economic and environmental assessments. Inoculation with P. veronii increased root depth by 45%, improved aboveground biomass, increased the ratio of culturable bacteria to Fusarium spp. from 6.1 to 10.3, and reduced Fusarium abundance by 29.4%. Structural equation modeling suggested that trophic support (42.1%), aggregate stabilization (27.4%), biocontrol (23.3%), and defense-related responses (7.2%) were the principal pathways associated with soil rehabilitation. Economic assessment indicated that the combined inoculation and mineral fertilization treatment provided the highest profitability, while environmental assessment estimated potential reductions in mineral fertilizer use and greenhouse gas emissions. These findings suggest that rhizosphere engineering using a native P. veronii strain represents a promising, economically viable, and climate-smart approach for improving the biological functioning of degraded Calcisols and supporting sustainable agricultural production. Full article

Agriculture faces the challenge of transitioning toward sustainable practices, driving the use of plant growth-promoting bacteria (PGPB). However, these bacteria suffer critical losses in viability due to environmental stress and drying processes. Although synthetic hydrogels offer protection, their low biodegradability and toxicity pose ecological risks, positioning dextran hydrogels produced by Leuconostoc sp. as a biocompatible biotechnological alternative, despite challenges related to their mechanical stability. The methodology employed consisted of systematic literature mapping in the Scopus database for the period 2010–2026. The search was conducted on 2 May 2026, using a defined search equation, and 447 documents were processed using RStudio (Bibliometrix), VOSviewer, and Plotly Studio to analyze trends and collaboration networks. The results of the systematic mapping reveal an exponentially growing field (R² = 0.998), led by Agricultural Sciences (23.5%) and Biochemistry (16%). China and India dominate scientific output in terms of volume, while Italy and the United States lead in qualitative impact, with researchers such as Cimini, Schiraldi, and Pandey as key references. An evolution is confirmed from the basic characterization of Leuconostoc sp. toward the development of matrices for immobilizing PGPB, reducing viability losses from 6 log to manageable levels of 4 log CFU. Cluster analysis shows a clear trend toward nanotechnology and “smart hydrogels” responsive to multiple stimuli. Finally, strategic gaps were identified in the creation of predictive release models, as well as an urgent need to democratize the technology through low-cost processes, essential aspects for consolidating sustainable precision agriculture. Full article

Microbial biostimulants and microbial plant protection products overlap in biological function, creating both R&D opportunities and regulatory challenges. In particular, multi-strain bacterial consortia may simultaneously affect nutrient mobilisation and abiotic stress tolerance, induce resistance, and demonstrate direct antagonism against phytopathogens. This multifunctionality complicates early product development because strain identity alone is sometimes insufficient in predicting product function, efficacy, or the most appropriate regulatory and claims strategy. Here, we used non-targeted LC-MS metabolomics as a hypothesis-generating tool to support formulation decisions for microbial consortia. Three bacterial consortia were compared: a full soil-oriented consortium C1 containing Bacillus spp., Rhodopseudomonas palustris, Nitrosomonas europaea, and Nitrobacter winogradskyi; a Bacillus-only consortium C2 intended for foliar stress-resilience applications; and a Bacillus-only consortium C3 grown with a chitin-related inducer to promote biocontrol-associated metabolism. Metabolomic profiling revealed clear differences between formulations. The full consortium C1 showed higher relative abundances of features putatively associated with biofertilising and growth support, whereas the Bacillus-only consortium C2 contained features putatively associated with biocontrol and induced resistance that were not detected in C1 under the applied criteria. The addition of the chitin-related inducer (C3) did not yield a completely distinct metabolite profile but increased the relative abundance of selected features putatively associated with biocontrol, while decreasing features putatively annotated as auxin-related or associated with abiotic stress responses. These results suggest that non-targeted metabolomics can help differentiate metabolic profiles putatively associated with biostimulant- and plant-protection-oriented formulations and thereby support prioritisation before extensive greenhouse or field testing. By linking formulation, medium composition, and microbial interactions to measurable metabolic signatures, metabolomics provides an evidence-based, hypothesis-generating framework for formulation development and the prioritisation of subsequent efficacy trials. Full article

Halotolerant plant growth-promoting bacteria offer a sustainable strategy to improve crop performance under saline conditions. This study evaluated Agave tequilana Weber var. Azul leaf juice was used as an alternative growth medium for Kocuria sediminis AS04, and the bacterium’s ability to alleviate salt stress in chiltepin (Capsicum annuum) was evaluated. The chiltepin seedlings were grown in a specialized chamber and exposed to higher salt levels (200, 400, and 600 mM NaCl) for 10 days. During this time, the protective effect of K. sediminis AS04, which was held in a polymer film, was examined. K. sediminis AS04 grew well in a medium containing 25% agave juice and urea, reaching a density of 1.3 × 10¹⁰ CFU mL⁻¹. Compared with conventional Tryptic Soy Broth, the medium formulated from agave leaf juice and urea could reduce the cost per kilogram of biomass by approximately 4-fold. Under severe salinity stress, plants inoculated with immobilized K. sediminis at 600 mM NaCl exhibited the highest shoot biomass (0.31 g⁻¹ plant), root length (50.7 mm), and proline accumulation (11.25 µmol g⁻¹ fresh weight), whereas uninoculated plants displayed reduced biomass (0.16 g plant⁻¹) and shorter roots (34.5 mm). At 600 mM NaCl, inoculation increased shoot biomass, root length, and plant survival by approximately 94%, 47%, and 200%, respectively, compared with uninoculated seedlings. This method values agro-industrial waste and enhances chiltepin performance under high-salinity conditions. It promotes sustainable production and helps create affordable inoculants for agricultural biotechnology. Full article

Bioprospecting of plant growth-promoting bacteria enables the identification of beneficial microbial resources with significant potential for sustainable agricultural applications. In this context, strain TRQ48 was isolated from a commercial field of wheat (Triticum turgidum L. subsp. durum) located in the Yaqui Valley, Mexico, with the aim of exploring its plant growth-promoting potential. The draft genome sequence presented a genomic size of 2,777,016 bp, 32.5% G + C content, 665,763 bp N50, 2 L50, and 19 contigs. Taxonomic affiliation demonstrated that strain TRQ48 belonged to Mammaliicoccus sciuri. Genome annotation identified 2756 coding DNA sequences (CDS) distributed into 259 subsystems, highlighting CDS associated with iron acquisition and metabolism, stress response, and virulence, disease, and defense, among others. Metabolic assays reflect the strain’s capacity to produce siderophores and auxins, relating these positive traits to significantly (p ≤ 0.05) promote growth of wheat shoot length (7.09%) and root and shoot dry weight (75% and 18.43%) compared to uninoculated wheat plants. Biosafety testing indicated that the strain is susceptible to commonly used antibiotics and lacks clinically relevant resistance profiles, matching genomic analysis, which did not reveal any critical virulence factors. Thus, although the presented results show that M. sciuri TRQ48 is a promising beneficial biosafe strain, further studies are still needed to evaluate its performance under agro-ecosystems at commercial levels. Full article