Search Results (1,680)

Two genetically engineered Bacillus subtilis strains, BMV9 and BsB6, were evaluated in terms of culture medium (effect of nutrients on surfactin yield) and potential biotechnological applications of surfactin in agriculture and the petrochemical industry. BMV9 (spo0A3; abrB*; ΔmanPA; sfp+) is, to date, the highest surfactin producer reported scientifically, and BsB6 is a sfp+ laboratory derivative strain that has also demonstrated considerable production potential. To assess their performance, fermentation experiments were conducted in shake flasks using two different culture media, a mineral salt medium and a complex medium, each supplemented with 2% (w/v) glucose. Lipopeptides (surfactin and fengycin) were extracted and quantified at multiple time points (up to 48 h) via high-performance thin-layer chromatography (HPTLC). Optical density, residual glucose, and pH were monitored throughout the cultivation. In parallel, microbial growth in both media were also validated in small-scale cultivation approaches. Antifungal activity of culture supernatants and lipopeptide extracts was tested against two Diaporthe species, key phytopathogens in soybean crops. Given the agricultural relevance of these pathogens, the biocontrol potential of lipopeptides represents a sustainable alternative to conventional chemical fungicides. Additionally, oil displacement tests were performed to evaluate the efficacy of surfactin in enhanced oil recovery (EOR), bioremediation, and related petrochemical processes. High-resolution LC-MS/MS analysis enabled structural characterization and relative quantification of the lipopeptides. Overall, these investigations provide a comprehensive comparison of strain production performance and the associated impact of cultivation media, aiming to define the optimal conditions for economically viable surfactin production and to explore its broader biotechnological applications in agriculture and the petrochemical industry. Full article

Selenium-enriched yeast is considered the most bioavailable dietary form of this trace element. It is already authorised for use in food and feed, making it a key vehicle for closing nutritional Se gaps worldwide. Understanding how selenium accumulation reshapes the amino-acid balance of yeast biomass is crucial for diet-related health benefits and optimising biotechnological processes that rely on high-quality microbial protein. The effect of selenium on yeast amino-acid metabolism is an important area of research due to its potential applications in biotechnology and functional food production. In the presented work, changes in the amino acid profile and protein quality in Saccharomyces cerevisiae ATCC 7090 and Rhodotorula glutinis CCY 20-2-26 cells grown in the presence of different selenium concentrations (0–40 mg Se⁴⁺/L) for 24 and 48 h were analyzed. The amino acid content was assessed, and the Chemical Score (CS) and adjusted Essential Amino Acid Index (EAAI) were determined. The results showed that moderate selenium concentrations (2–10 mg Se⁴⁺/L after 24 h) promoted the accumulation of essential amino acids, such as lysine (53.3 mg/g) and valine (38.0 mg/g) in S. cerevisiae and lysine (42.8 mg/g) and valine (41.6 mg/g) in R. glutinis. High values of protein quality indices were also obtained under the same conditions—CS exceeding 200% and adjusted EAAI reaching 1.71 for S. cerevisiae and 2.05 for R. glutinis. It is worth noting, however, that EAAI was presented without methionine and tryptophan. In turn, higher selenium concentrations and longer cultivation time decreased these parameters, especially in the case of S. cerevisiae. The obtained data confirm that R. glutinis may be a promising source of high-quality protein in selenium-enriched products. Full article

Tomato leafminer (Tuta absoluta) significantly affects tomato (Solanum lycopersicum) and eggplant (Solanum melongena) crops worldwide, with its feeding patterns being closely associated with its gut microbiota. We aimed to compare the cultivable gut bacteria of T. absoluta larvae fed on tomato and eggplant to investigate their role in host adaptation. Gut bacteria were cultivated on Luria–Bertani broth, nutrient agar, and Brain Heart Infusion media under different temperature conditions, followed by morphology- and 16S rRNA-based identification. Notably, both feeding groups revealed distinct gut bacterial community structures. Tomato-fed larvae harbored bacteria spanning eight species, five genera, four families, and two phyla. In contrast, eggplant-fed larvae exhibited greater microbial diversity, encompassing 15 species, 10 genera, 9 families, and 3 phyla, including unique genera such as Pseudomonas and Pectobacterium, which was attributed to the host plant contribution. Enterococcus mundtii was the most dominant bacterium, and species such as Bacillus wiedmannii and Micrococcus luteus were most thermotolerant. Overall, these findings highlight the importance of multi-condition culture approaches for thoroughly characterizing insect gut microbiota and underscore the role of host plants in pest adaptability by modulating gut microbial communities, providing new insights for developing sustainable control strategies utilizing “plant–insect–microorganism” interactions. Full article

Coffea, a plant species of significant agricultural value used in coffee production, is a key commodity that supports the livelihoods of millions of people worldwide. However, coffee cultivation faces substantial threats from various pathogens, including Pseudomonas coronafaciens pv. garcae (Pcg), the causative agent of bacterial blight. This pathogen compromises coffee plant health, leading to reduced yields and plant death and impacting farmers and large-scale producers. Understanding the mechanisms underlying resistance to Pcg in the leaves of the resistant IAC 2211-6 Coffea arabica accession is crucial for developing effective control strategies. This study aimed to identify candidate biomarkers of resistance by comparing the leaf metabolome of (i) the resistant IAC 2211-6 and the susceptible IAC 125 RN Coffea arabica accessions and (ii) Pcg-infected and uninfected leaves. Untargeted metabolomics revealed distinct metabolic profiles between accessions. Flavonoids were more abundant in susceptible leaves. In contrast, resistant leaves showed increased levels of pipecolic acid ethyl ester, a structural derivative of a key systemic acquired resistance signal, and spiropreussione B, a compound associated with fungal endophytes. These findings highlight candidates potentially linked to resistance and suggest that systemic signaling and beneficial microbial interactions may contribute to resilience. Full article

To screen efficient microbial coating formulations and explore their effects on the growth of alfalfa and soil properties, ‘Gannong No. 3’ alfalfa was used as the experimental material. A single-factor randomized block field experiment was conducted with eight treatments (CK as bare seeds, BC as adhesive filler coated agent, J1-J3 as rhizobium agent, growth-promoting bacteria agent, and rhizobium plus growth-promoting bacteria seed soaking, respectively, B1-B3 as rhizobium, growth-promoting bacteria, and rhizobium plus growth-promoting bacteria coating agents, respectively). This study analyzes the effects of different microbial coating formulations on alfalfa, including its production performance and nutritional quality, as well as on soil properties. Comprehensive analysis shows that the growth-promoting microbial coating (B2) is the optimal formulation. It can simultaneously optimize alfalfa production performance, enhance nutritional quality, improve soil particle composition, and increase soil enzyme activity, achieving a synergistic improvement of both alfalfa and the soil ecosystem. Its application effect is significantly better than other treatments and can provide important theoretical support and practical reference for the development and application of efficient microbial seed coatings in high-quality alfalfa cultivation. Full article

Pseudomonas has been revealed as an important member of plant probiotics, with its rich species diversity implying complementary plant growth-promoting (PGP) traits. However, information on Pseudomonas species in the microecology of Angelica sinensis and medicinal plants in general remains to be further investigated. This study examined the microecological characteristics, PGP traits, and their underlying molecular mechanisms of Pseudomonas. Filling this gap will provide an important reference for microbial community design centered on dominant functional bacterial genera. In this study, we characterized the microecological traits, PGP properties, and their underlying molecular mechanisms of Pseudomonas strains. Microbiome analysis identified Pseudomonas as the dominant genus in the rhizosphere and a core endophytic genus, exerting significant influences on both (path coefficients = 0.971, 0.872). Comparative phenomics suggested potential functional complementarity among different strains. Our observations revealed significant differentiation in PGP traits: P. umsongensis X08 showed exceptional performance in IAA and siderophore production (IAA: 1.24 mg/mL, siderophore halo diameter: 2.04 cm); P. frederiksbergensis X06 exhibited advantages in ACC deaminase activity and potassium solubilization; and P. allii X32 demonstrated high organic phosphorus solubilization capability (3.98 mg/L). Finally, genomic data revealed that P. allii X32 possesses a rich repertoire of PGP-related genes and metabolic pathways, providing a basis for establishing molecular mechanistic hypotheses for these traits. In summary, Pseudomonas strains from different species, which exhibit complementary probiotic functions without antagonism in the A. sinensis microecosystem, provide valuable microbial resources for the ecological cultivation of A. sinensis. Full article

In precision agriculture, the delineation of Management Zones (MZs) is essential for optimizing input use efficiency and site-specific nutrient management. MZs are established based on spatial variability derived from remote sensing data—such as Normalized Difference Vegetation Index (NDVI) from satellite or UAV-based imagery—and yield maps collected during harvest. However, the microbial community composition of the soil is often overlooked in MZ delineation. To address this gap, we investigated the soil bacterial community structure across different MZs in an arable field. The zones were delineated using NDVI data, soil profiles were described, and bulk soil samples were collected. Soil physicochemical parameters were analyzed in parallel with 16S rRNA gene amplicon sequencing to characterize bacterial community composition and diversity. The results demonstrated that soil texture and soil organic matter content were the primary drivers influencing bacterial community structure across the field. Moreover, patterns in microbial composition aligned closely with MZ delineations, indicating that microbial profiles could aid in better understanding and supporting the nutrient management practices. Our findings suggest that soil microbiological data can enhance the stability and biological relevance of MZ definitions, thereby improving resource allocation, soil health management, and overall sustainability in precision farming systems. Full article

The worldwide population is anticipated to reach 10.12 billion by the year 2100, thereby amplifying the necessity for sustainable agricultural methodologies to secure food availability while reducing ecological consequences. Conventional synthetic pesticides, while capable of increasing crop yields by as much as 50%, present considerable hazards such as toxicity, the emergence of resistance, and environmental pollution. This review examines biopesticides, originating from microbial (e.g., Bacillus thuringiensis, Trichoderma spp.), plant, or animal sources, as environmentally sustainable alternatives which address pest control through mechanisms including antibiosis, hyperparasitism, and competition. Biopesticides provide advantages such as biodegradability, minimal toxicity to non-target organisms, and a lower likelihood of resistance development. The global market for biopesticides is projected to be valued between USD 8 and 10 billion by 2025, accounting for 3–4% of the overall pesticide sector, and is expected to grow at a compound annual growth rate (CAGR) of 12–16%. To mitigate production costs, agro-industrial byproducts such as rice husk and starch wastewater can be utilized as economical substrates in both solid-state and submerged fermentation processes, which may lead to a reduction in expenses ranging from 35% to 59%. Strategies for process intensification, such as the implementation of intensified bioreactors, continuous cultivation methods, and artificial intelligence (AI)-driven monitoring systems, significantly improve the upstream stages (including strain development and fermentation), downstream processes (such as purification and drying), and formulation phases. These advancements result in enhanced productivity, reduced energy consumption, and greater product stability. Patent activity, exemplified by 2371 documents from 1982 to 2021, highlights advancements in formulations and microbial strains. The integration of circular economy principles in biopesticide production through process intensification enhances the safety, quality, and sustainability of food systems. Projections suggest that by the 2040s to 2050s, biopesticides may achieve market parity with synthetic alternatives. Obstacles encompass the alignment of regulations and the ability to scale in order to completely achieve these benefits. Full article

The increasing volume of produced water (PW) generated by oil extraction activities has intensified the need for environmentally sustainable strategies that enable its reuse and valorization. Biotechnological approaches, particularly those involving the microbial production of value-added compounds, offer a promising route for transforming PW from an industrial waste into a useful resource. In this context, bacterial exopolysaccharides (EPS) have gained attention due to their diverse functional properties and applicability in bioremediation, bioprocessing and petroleum-related operations. This study evaluated the potential of Lelliottia amnigena to synthesize EPS using oilfield PW as a component of the culture medium in stirred-tank bioreactors. Three conditions were assessed: a control using distilled water (dW), PW diluted to 25% (PW25%) and dialyzed PW (DPW). Batch experiments were conducted for 24 h, during which biomass growth, EPS accumulation and dissolved oxygen dynamics were monitored. Post-cultivation analyses included elemental and monosaccharide composition, scanning electron microscopy and rheological characterization of purified EPS solutions. EPS production varied among treatments, with dW and DPW yielding approximately 9.6 g L⁻¹, while PW25% achieved the highest productivity (17.55 g L⁻¹). The EPS samples contained fucose, glucose and mannose, with compositional differences reflecting the influence of PW-derived minerals. Despite reduced apparent viscosity under PW25% and DPW conditions, the EPS exhibited physicochemical properties suitable for biotechnological applications, including potential use in fucose recovery, drilling fluids and lubrication systems in the petroleum sector. The EPS also demonstrated substantial adsorption capacity, incorporating salts from PW and contributing to contaminant removal. This study demonstrates that PW can serve both as a substrate and as a source of functional inorganic constituents for microbial EPS synthesis, supporting an integrated approach to PW valorization. These findings reinforce the potential of EPS-based bioprocesses as sustainable green technologies that simultaneously promote waste mitigation and the production of high-value industrial bioproducts. Full article

Studies of complex natural environments often focus on either biodiversity or on isolating organisms with specific properties. In this study, we sought to widen this perspective and achieve both. In particular, hypersaline ecosystems, such as the Sečovlje salt pans (Slovenia), are particularly promising sources of novel bioactive compounds, as their microorganisms have evolved adaptations to desiccation and high light intensity stress. We applied shotgun metagenomics to assess microbial biodiversity under low- and high-salinity conditions, complemented by isolation and cultivation of photosynthetic microorganisms. Metagenomic analyses revealed major shifts in community composition with increasing salinity: halophilic Archaea became dominant, while bacterial abundance decreased. Eukaryotic assemblages also changed, with greater representation of salt-tolerant genera such as Dunaliella sp. Numerous additional microorganisms with biotechnological potential were identified. Samples from both petola and brine led to the isolation and cultivation of Dunaliella sp., Tetradesmus obliquus, Tetraselmis sp. and cyanobacteria Phormidium sp./Sodalinema stali, Leptolyngbya sp., and Capilliphycus guerandensis. The newly established cultures are the first collection from this hypersaline environment and provide a foundation for future biodiscovery, production optimization, and sustainable bioprocess development. The methods developed in this study constitute a Toolbox Solution that can be easily replicated in other habitats. Full article

Vegetable cultivation is currently facing complex challenges related to climate change, with negative repercussions on plant performance. In this scenario, the employment of eco-friendly agronomic tools capable of boosting plant tolerance to abiotic stresses is fundamental. Among them, the use of non-microbial biostimulants, such as seaweed extracts (SwEs), and microelements, like selenium (Se), is considered an efficient approach to overcome abiotic stresses. In this experiment, the performance of chicory plants cultivated under three different irrigation levels (100%, 75% or 50% of substrate water holding capacity) and treated with SwE, Se or their combination (SwE + Se) was evaluated. The results revealed that drought stress significantly decreased growth, productivity and relative water content but increased soluble solid content, dry matter percentage, and proline and malondialdehyde concentrations. The application of Swe, Se or Swe + Se enhanced growth, productive features and soluble solid content and reduced dry matter percentage, proline and malondialdehyde compared to the control. Based on our results, Se and SwE combined application could be a valuable approach to face moderate drought stress on curly endive plants and improve productive and quality traits. Full article

Drought stress severely impacts agricultural productivity, yet mechanisms underlying microbial enhancement of plant drought tolerance remain poorly understood. This study investigated whether Sphingobacterium nripensae DR205 exhibits drought-specific plant growth promotion through conditional metabolic activation. We combined plant cultivation experiments, genome sequencing, and comparative transcriptomics to evaluate DR205 responses under normal and drought conditions with or without root exudates. DR205 showed minimal growth promotion under normal conditions but enhanced plant biomass by 74–344% specifically under drought stress. Genome analysis revealed complete pathways for both stress tolerance (osmolyte biosynthesis and antioxidant systems) and plant interaction (IAA production and nutrient mobilization). Transcriptomics uncovered dramatic metabolic reprogramming under drought, with branched-chain amino acid (BCAA) biosynthesis genes shifting from 27-fold suppression under root exudates to 17-fold upregulation under drought. Lysine biosynthesis showed similar drought-specific activation patterns. Critically, drought signals overrode plant signals maintaining BCAA activation regardless of root exudate presence and ensuring metabolic investment in plant support occurred specifically during water deficit. This conditional mutualism represents a novel bacterial strategy where plant support is selectively activated during environmental stress. These findings challenge conventional PGPR paradigms and offer new approaches for developing climate-resilient agricultural systems through targeted application of stress-responsive beneficial microbes. Full article

Domestication reduced the genetic diversity in modern crops, often resulting in reduced resilience to biotic and abiotic stress. Evidence is now accumulating that domestication also altered the structure and function of root-associated microbiomes, creating new opportunities to harness beneficial microbes for breeding and crop improvement. Using multi-region 16S rRNA sequencing, we compared the rhizosphere and endosphere bacterial communities of cultivated tomato (Solanum lycopersicum cv. Moneymaker) with six wild relatives (S. pimpinellifolium, S. huaylasense, S. peruvianum, S. chilense, S. habrochaites, and S. pennellii) spanning the main wild lineages within Solanum sect. Lycopersicon. Bacterial community structure in the rhizosphere was broadly conserved across all seven hosts, and diversity remained comparable among genotypes. Despite this overall stability, the rhizosphere microbiomes were ordered along a gradient consistent with host phylogeny, with Moneymaker clustering near S. pimpinellifolium, the four green-fruited Eriopersicon species forming a cohesive block, and S. pennellii occupying the most distinct position. Within this hierarchy, individual hosts showed specific recruitment preferences, including enrichment of Streptomycetaceae in S. pimpinellifolium, Bacillaceae in S. chilense, and contrasting patterns of nitrifiers among Eriopersicon species and S. pennellii. Differential abundance testing in the endosphere revealed consistent reductions in several bacterial families in wild accessions, alongside the enrichment of Streptomycetaceae and Rhodobiaceae in multiple wild species. Overall, our study suggests that domestication exerted a modest effect on tomato root microbiomes, while wild relatives retained microbial association traits that could be harnessed in microbiome-informed breeding to improve resilience in cultivated tomato. Full article

New Zealand’s only tea (Camellia sinensis) plantation supplies a niche market for organically produced high value tea but faces challenges from climatic conditions and the decision to use only organic production methods. Fungi from the genus Trichoderma have been commercialised in New Zealand and elsewhere as disease-suppressing and plant growth-promoting agents. However, the potential benefits of using Trichoderma as a microbial biostimulant for tea cultivation have not been investigated in New Zealand. The ability of T. atroviride application to stimulate tea plant growth at a tea plantation was investigated over one year of production. The study involved foliar application of the biostimulant either once, twice or three times, one month apart, using 12 g of a commercially formulated spore mixture of four strains of T. atroviride per 5 m² of experimental plots. Treatment with T. atroviride significantly increased tea yield by between 17% and 28% compared to the control over the harvesting season, but there were no statistically significant yield differences among the number of applications. The foliar applied T. atroviride was not detected in the soil or root samples six months after application, in either a soil metabarcoding analysis or on re-isolation media. This was likely due to the dense tea foliage and ground cover under the tea plants which impeded its movement to the soil. While the specific nature of T. atroviride interaction with perennial crops like tea is not known, in this trial it appeared to have remained on the phyllosphere and provided biostimulation without reaching the soil. Full article

The JinEr mushroom (“Golden Ear”), a globally rare edible and medicinal macrofungus, comprises a symbiotic complex formed by the symbiotic association of Naematelia aurantialba (Tremellomycetes) and Stereum hirsutum (Agaricomycetes). However, the interactions between these fungi and their associated microbiome remain poorly understood. This study employed high-throughput amplicon sequencing, in situ microbial isolation and culture, and microbial confrontation assays to analyze microbial diversity, community structure, and potential functional roles of the endomycotic bacterial community within JinEr basidiomata and its cultivation substrate. Molecular analysis confirmed the heterogenous composition of the basidiomata, revealing N. aurantialba constitutes less than 20% of the fungal biomass, while S. hirsutum predominates, accounting for approximately 80%. Endomycotic fungi accounted for 0.33% (relative abundance) of the fungal community. Prokaryotic analysis identified Delftia and Sphingomonas as the dominant endomycotic bacterial genera within basidiomata, comprising 85.42% of prokaryotic sequences. Endomycotic bacterial diversity differed significantly (p < 0.05) between basidiomata and substrate, indicating host-specific selection. Cultivation-based approaches yielded 140 culturable bacterial isolates (spanning four families and seven genera) from basidiomata core tissues. In vitro co-culture experiments demonstrated that eight representative bacterial strains exhibited compatible growth with both hosts, while one Enterobacteriaceae strain displayed antagonism towards them. These findings confirm that the heterogeneous JinEr basidiomata harbor a specific prokaryotic assemblage potentially engaged in putative symbiotic or commensal associations with the host fungi. This research advances the understanding of microbial ecology in this unique fungal complex and establishes a culture repository of associated bacteria. This collection facilitates subsequent screening for beneficial bacterial strains to enhance the JinEr cultivation system through the provision of symbiotic microorganisms. Full article