Chemical and Biological Technologies in Agriculture最新文献

Background

During storage, fruits and vegetables are susceptible to the pathogens responsible for postharvest decay. Various tools are available to manage these issues, but not all are environmentally sustainable. Low-temperature plasma (LTP) has garnered significant attention among the most promising and eco-friendly solutions. LTP can be applied directly or indirectly, offering versatile applications. One notable indirect application is the utilization of plasma-activated water (PAW). In this study, we investigated the efficacy of an aerosol made by droplets of water nebulized by the effluent gases of a plasma discharge as a delivery method of PAW to substrates. We named this novel application, reported for the first time, plasma-activated fog (PAF). In this work, it was tested as a new alternative technology for fruit decontamination against postharvest fungal pathogens and pesticide residues.

Results

PAF was generated via volume dielectric barrier discharge (VDBD) in a jet-like configuration and was applied to evaluate the in vitro effects on the conidial germination of major fungal postharvest pathogens, such as Alternaria alternata, Aspergillus carbonarius, Botrytis cinerea, Cladosporium sp., Monilinia fructicola, Penicillium italicum, Penicillium expansum and Rhizopus sp. Differences in fungal sensitivity to PAF were recorded, with A. alternata showing the lowest sensitivity to treatments. For most species, complete spore inhibition was obtained after 3–5 min of exposure. The efficacy of PAF against fungal rot was assessed on table grapes and strawberries, revealing a reduction in the percentage of rotted fruits exposed to 10 min of treatment, ranging from 45 to 80% on table grapes and from 52 to 74% on strawberries. PAF treatments also reduced pesticide residues on grape bunches and strawberry fruits, with various results depending on the active ingredient, with reductions of up to 96% for abamectin among insecticides and acaricides, and up to 38% for the fungicide fenhexamid.

Conclusions

The results obtained in the present work have the potential to refine and optimize PAF treatment conditions for the antimicrobial decontamination of plant products.

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Industrial hemp (Cannabis sativa L. subsp. sativa) is a multipurpose crop widely cultivated for its fibers, seeds, and oils. Despite the common use of hemp stems for fiber production in textiles and construction, they are frequently discarded as agricultural waste. This study aimed to enhance the utilization of hemp stems through the optimization of ultrasound-assisted extraction (UAE) employing aqueous propylene glycol solvent system as the extraction solvent, guided by Box–Behnken design (BBD). The optimal extraction parameters—an extraction duration of 30 min, a solvent–solute ratio of 28.25 mL/g, and a PG concentration of 32.72%—resulted in a hemp stem extract (HUPG) enriched with bioactive constituents exhibiting significant antioxidant activity. Following analysis by LC–QTOF–MS/MS, a total of 18 phytochemicals were detected, including isofeuric acid, m-coumaric acid, and chelidonic acid. HUPG exhibited antibacterial activity against Staphylococcus aureus, Streptococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa, and anti-inflammatory effects through 5-lipoxygenase inhibition and NO radical scavenging (1.41 ± 0.38 mg GAE/g). In LPS-induced RAW 264.7 macrophages, HUPG demonstrated inhibitory effect on NO production. Moreover, it enhanced wound closure in HaCaT cells (51.92 ± 6.05% at 10 mg/mL). These findings highlight the promise of HUPG as a sustainable source of bioactive compounds with potential applications in cosmetic and pharmaceutical formulations.

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Background

The rational utilization of agricultural straw is crucial for improving soil fertility and reducing greenhouse gas emissions (GHGs). The purpose of this study was to investigate how rice (RB) and maize (MB) straw-derived biochar, produced at varying pyrolysis temperatures and application rates, regulated straw decomposition and GHGs by reshaping soil microbial communities and physicochemical properties.

Results

Through 90-day incubation experiments, it was found that biochar produced using low temperature (300 °C) at 2.5–5.0% application rates significantly accelerated straw decomposition by 14.94–36.04% and reduced CH₄ and N₂O emissions by up to 37.84–90.26% and 41.60–91.10%, respectively. Application of biochar produced using low-temperature method enhanced the soil organic matter (9.92–29.26%), pH (1.82–11.32%), and soil enzyme activities (cellulase: 7.84–22.90%, β-glucosidase: 49.92–75.32%), while altering microbial communities, especially increasing copiotrophic bacteria (e.g., Proteobacteria, Ascomycota) in rice grown soils linked to rapid decomposition and reducing Ascomycota dominance in maize soil with altering nutrient dynamics due to higher C/N ratios. Path analysis indicated strong biochar–enzyme–decomposition linkages (normalized coefficient: 0.92), emphasizing microbial community structure as a pivotal mediator. In contrast, biochar produced through high pyrolysis temperatures (mentioning the temperature) diminished effectiveness due to higher structural stability and potential limitations in microbial activity.

Conclusions

Our results indicate that application rates of 2.5–5.0% biochar produced through low temperature can effectively balance straw decomposition and GHGs reduction, offering a sustainable approach for straw management in rice and maize cultivation. These findings provide scientific support for optimizing biochar use in agriculture, contributing to improved soil health and climate change mitigation.

Graphical Abstract

Plant growth is intricately regulated by soil ecosystems, where dynamic interactions between plants and soil metabolites shape root development. As critical mediators of these interactions, soil metabolites not only reflect biogeochemical cycling but also directly modulate root morphogenesis by eliciting stimulatory or inhibitory responses. To decode the mechanisms driving peanut (Arachis hypogaea L.) root system development, utilizing UPLC-HRMS we profiled 702 soil specific metabolites across soil samples collected from five different regions. Further 118 differentially expressed metabolites were identified in collected soil samples, and 10 metabolites were selected to validate their function associated with peanut root length phenotype. Through systematic screening, four root promoting metabolites (nicotinamide, carbendazim, vanillic acid, and raffinose) and four phytotoxic compounds (phthalic acid, myristic acid, formononetin, and syringic acid) were identified. Our results showed that the seedlings treated with nicotinamide, carbendazim, vanillic acid, and raffinose promotes root elongation by up to 28.3% as compared to untreated seeds. Whereas, seedlings treated with phthalic acid, myristic acid, formononetin, and syringic acid, suppressed root growth by 56.6%, demonstrating a bimodal inhibition pattern. Dose response assays revealed hierarchical efficacy among these metabolites, with carbendazim and formononetin representing the most potent enhancer and suppressor, respectively. Current findings reveal a causal link between soil metabolite composition and peanut root development, providing a biochemical basis for harnessing soil specific metabolites in precision agriculture.

Graphical Abstract

Cordyceps sinensis is widely utilized in China as an edible and medicinal fungus for the treatment of immunodeficiency-related disorders. Evidence suggests that polysaccharides are the principal bioactive components responsible for its immunostimulatory effects. However, the physicochemical properties, bioactivities, and structure–function relationships of these polysaccharides remain inadequately elucidated. In this study, four distinct crude polysaccharides from wild Cordyceps sinensis (WCP) were isolated using stepwise ethanol precipitation at final concentrations of 20%, 40%, 60%, and 80% (v/v). These fractions were designated as WCP-20, WCP-40, WCP-60, and WCP-80, respectively. Results demonstrated that the molecular weight (MW) of WCP decreased as the ethanol concentration increased. High-MW fractions (WCP-20/-40) exhibited high glucose content, a partially triple-helical structure, levorotation (−), and greater thermal stability. In contrast, the low-MW fractions (WCP-60/-80) were enriched in galactose and mannose, exhibited a higher branching density, and dextrorotation ( +). Furthermore, this study revealed that WCPs activated macrophages by enhancing phagocytosis and stimulating the secretion of nitric oxide and interleukin-1 beta. These immunostimulatory effects were mediated through the MAPK/NF-κB signaling pathway. Specifically, WCP-20 triggered macrophage activation via the ERK/JNK/p65 pathway, with P38/ERK/JNK pathway for WCP-40, P38/ERK/JNK/p65 pathway for WCP-60, and JNK/p65 pathway for WCP-80. Correlation analysis revealed that the immunostimulatory effects of WCPs were closely linked to their monosaccharide composition and secondary structures. These findings established that the physicochemical properties of WCP were critical determinants of precise immune modulation. This study provided a foundational reference for developing precision polysaccharide-based immune-enhancing nutraceuticals.

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Background

Mineral-dissolving rhizobacteria are considered ecological friendly rhizonutrifying agents capable of promoting rhizospheric enzymatic activities, microbial biomass, and nutrient availability even under nutrient-deficient alkaline soil conditions. However, comprehensive studies on their effectiveness in calcareous soil are lacking. The current study hypothesized that beneficial rhizobacteria improve soil biochemical properties in calcareous soil through their impact on enzymatic activities, microbial biomass, and nutrient availability in the rhizosphere.

Methods

Rhizobacterial strains were isolated from wheat rhizosphere and characterized in vitro for their mineral solubilization potential, production of beneficial metabolites, and various enzymatic activities. A pot experiment was conducted to investigate the effect of sole and co-inoculation treatments on wheat growth, grain attributes, nutrient availability in soil and absorption in plants, soil enzymatic activities, and microbial biomass accumulation in wheat rhizosphere under calcareous soil conditions.

Results

The most effective mineral-dissolving rhizobacteria were identified as Bacillus altitudinis (strains SAM1, SAM7, SAM13, and SAM15) and Bacillus cereus (strain SAM9) through 16S rRNA partial gene sequencing. These strains demonstrated the dissolution of insoluble tricalcium phosphate, mica, zinc oxide, and manganese oxide, and promoted nutrient availability in the soil by producing organic acids. Inoculation enhanced wheat growth and grain development by promoting nutrient acquisition and stimulating rhizospheric microbial activity. Both sole and co-inoculation with rhizobacterial strains significantly increased soil enzymatic activities, microbial biomass carbon, nitrogen, and phosphorus, and nutrient availability in the wheat rhizosphere through organic matter decomposition. Among treatments, sole inoculation with B. cereus SAM9 and co-inoculation with B. cereus SAM9 + B. altitudinis SAM13 demonstrated the most dominant increase in wheat growth and grain attributes, nutrient availability in soil and absorption in plants, deposition of microbial biomass, and soil enzymatic activities.

Conclusions

The sole inoculation with B. cereus SAM9 and co-inoculation with B. cereus SAM9 + B. altitudinis SAM13 showed strong potential as bioinoculants for calcareous soils. These strains could be effectively integrated into commercial biofertilizer formulation as sustainable alternatives or supplements to chemical fertilizers, enhancing soil productivity and crop performance.

Graphical Abstract

Background

Soybean–maize rotation is an effective strategy for addressing the challenges associated with continuous soybean cropping. However, the effects of maize frequency in cropping sequences on soil fungal functions and their associations with soybean yields remain unclear. Through a 12-year field study comparing continuous soybean (CS), maize–soybean (MS), and maize–maize–soybean (MMS) systems, fungal community functions, system-specific taxa, and bacterial–fungal inter-kingdom co-occurrence patterns were analyzed.

Results

In contrast to conventional assumptions, CS enriched symbiotic fungi and suppressed pathogens, suggesting adaptive disease resilience. Integrating maize into soybean cropping systems increased the complexity of bacterial–fungal cross-kingdom co-occurrence networks. While the MS system increased the relative abundances of plant pathogens and saprotrophs, the MMS system stabilized fungal functions and inhibited plant pathogen accumulation. The system-specific taxa identified in the CS and MMS systems included potential plant growth-promoting microbes and were associated with the relative abundances of pathogens and saprotrophic fungi as well as soybean yield. This relationship may represent a critical link between fungal function and soybean production.

Conclusions

These findings indicate that integrating maize into soybean rotations, especially in the MMS system, can stabilize fungal functions and mitigate pathogen accumulation, ultimately increasing soybean yield. These results underscore the importance of tailored crop rotation practices to optimize soil microbial communities for sustainable agricultural production.

Graphical Abstract

Background

Plant-derived substances have long been valued as eco-friendly pesticides, with pyrethrum flowers recognized for their insecticidal properties since the nineteenth century. Over time, pyrethrum extracts became widely adopted as a natural, effective, and relatively safe green pesticide. However, the high production costs of these natural compounds prompted the development of synthetic pyrethroids, such as cypermethrin, which dominate the market today. While these synthetic alternatives offer effectiveness in pest control, they also present environmental concerns, such as pest resistance and toxicity to aquatic organisms. This has led some countries to continue using natural pyrethrins, resulting in large amounts of pyrethrum residue waste.

Results

In response to the need for sustainable solutions, we focused on repurposing these residues by isolating and evaluating 11 pyrethroid-related compounds. Among them, pyrethrindreg II, first isolated from natural sources, exhibited the highest insecticidal activity. Morphological observation and molecular docking revealed that pyrethrindreg II acts as a promising voltage-gated sodium channel (VGSC) inhibitor. The quantification of esterase-β, esterase-α, and GST concentrations explains the biochemical responses of pyrethrindreg II in Armigeres subalbatus. Density functional theory (DFT) calculations provide insight into its relatively weaker activity compared to the positive control, cypermethrin.

Conclusions

Pyrethrindreg II exhibited significantly lower toxicity, indicating its potential as a safer, greener alternative to synthetic pyrethroids.

Graphical Abstract

Background

The influence of various environmental factors on the formation of different morphological forms of soil organic matter has been extensively studied, but there is still uncertainty about how time spent in solution affects the evolution and possible transformation of the morphological structures of soil humic substances.

Methods

The transmission electron microscopy (TEM) with negative contrast staining by uranyl acetate was used to study morphological differences between soil humic acids (HAs) and their individual electrophoretic fractions before and after 150 days of incubation in the same solution under constant environmental conditions.

Results

For the first time, it was found that during 150 days of incubation in constant environmental conditions, soil humic samples can aggregate by two fundamentally different ways, forming vesicle-like or ribbon-flat/sheet-like supramolecular morphological structures.

Conclusions

The types of morphological supramolecular structures observed using TEM were found to be related to different chemical compositions and physical–chemical properties of soil humic substances. These data could be relevant to better understanding the overall makeup of soil HAs, their structural organization, and various ecological and biogeochemical functions.

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Objectives

This study explores Russelia equisetiformis as a sustainable source for the green synthesis of antifungal nanomaterials. In response to increasing phytopathogenic fungi and environmental issues, it focuses on the fabrication of manganese nanoparticles (MnONPs), nitrogen-doped carbon dots (N-CDs), and their nanocomposite (MnO NPs@N-CDs) using R. equisetiformis extract.

Methods

The synthesized nanomaterials were characterized by UV–Vis spectrophotometry, FTIR, DLS, TEM, and EDX to confirm nanoparticle formation. Their antifungal effectiveness was evaluated against Sclerotinia sclerotiorum, Fusarium equiseti, and Fusarium venenatum. Additionally, bioactive metabolites were identified via LC–QTOF-MS, and their antifungal activity, pharmacokinetic profiles, and toxicity levels were assessed through computational tools.

Results

Nanomaterials produced from R. equisetiformis extract significantly reduced fungal growth, highlighting their potential as eco-friendly solutions for plant disease control. Most metabolites exhibited favorable safety profiles with minimal predicted cardiotoxicity and mutagenicity, indicating their promise as safe fungicides.

Conclusion

R. equisetiformis provides compounds with effective antifungal activity and low toxicity, offering a promising, environmentally friendly alternative to conventional chemical fungicides for sustainable plant disease management. Further research is essential to expand their application in agriculture.

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