Chemical and Biological Technologies in Agriculture最新文献

A wide variety of eco-friendly and at zero waste techniques are developed for biomass conversion and valorization of its residues and by-products such as water fraction and organic residues which could be further utilized. The wastewater reuse is one of the best strategies for water security, sustainability, and resilience. To date, the municipal wastewater was the most widely used, nowadays the innovative technologies for biomass conversion and energy production allow the recovery of wastewater with better and safer features than the municipal effluents. Depending on the moisture content of the starting feedstock, the hydrothermal liquefaction process (HTL) generates also up to 95% of wastewater (HTL–WW) generally rich in nitrogen, phosphorus, and sulfate as well as micronutrients and minerals. Although it is currently recycled through various biological systems such as microalgae cultivation and anaerobic digestion, the possibility of using the wastewater from HTL process as irrigation water for agricultural purpose is discussed representing a source of crop nutrients for the high amount of organic and inorganic compounds and a new approach in contributing to reduce the increasing pressure on freshwater resources.

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The total polysaccharides extracted from Laetiporus sulphureus fruiting bodies by ultrasound-assisted complex enzyme method were separated by freeze–thaw combined with fehling reagent to prepare purified polysaccharide (LSPS1). The results of monosaccharide composition and molecular weight distribution demonstrated that LSPS1 contained galactose (51.83%), mannose (26.89%), fucose (16.13%) and glucose (5.15%), and the molecular weight was around 17.3 kDa. Methylation analysis indicated that the backbone of LSPS1 consisted of 1,6-Galp residues, branched at O-2 of Galp with t-Manp, t-Fucp and t-Glcp residues as side chains. In addition, LSPS1 was used for the synthesis of SeNPs based on the redox system of sodium selenite and ascorbic acid. The L. sulphureus polysaccharide selenium nanoparticles (LSPS1–SeNPs) were characterized by UV, FT-IR, ICP-MS, EDX, DLS and SEM, inferring that LSPS1–SeNPs were stabilized with spherical and granular surface structure as well as a mean particle size of 96.72 ± 1.12 nm. Both of LSPS1 and LSPS1–SeNPs possessed strong antioxidant and hypoglycemic activities while the effects of LSPS1–SeNPs were superior to LSPS1. The findings provided valuable structural information for L. sulphureus polysaccharide, and will promote the application of SeNPs by L. sulphureus polysaccharide in potential antioxidant agent and hypoglycemic candidate.

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Background

Synthetic hydrophilic polyelectrolytes are considered as perspective tools to optimize soil properties and find increasing applications in agricultural technologies. One possible polyelectrolyte-based soil conditioner that has shown promise for improving soil hydrophysical properties is hydrolyzed polyacrylonitrile (HYPAN), linear polyanion. Combinations of HYPAN with humic substances in binary polymer-humic soil amendment presumably could provide a synergistic impact. In this study we investigated the effects of HYPAN, two different potassium humates (from lignite and lignosulfonate), and binary compositions of HYPAN with humates in the ratios of 1:1 and 1:2, on soil microbiological activity. We applied polymer solutions (0.9% on a dry matter basis) in a lab experiment and examined how they affected soil respiration, microbial biomass, metabolic quotient, and the decomposition rate constant in soil–polymer mixtures. A concurrent set of studies involved spiking soil–polymer mixes with heavy metals (copper, zinc, lead and cadmium).

Results

In uncontaminated soil–polymer mixtures both humates stimulated the activity of soil microorganisms, expressed in increased basal respiration, microbial biomass, and mitigation of HM toxicity. The effects of binary polymer-humic formulations and HYPAN were comparable to and close in size to those of humates. On the 90th day, humates increased microbial respiration by 54–77% and HYPAN alone by 30%. Binary compositions were more efficient when combined with humate from lignosulphonate. The maximum increase in microbial biomass was obtained with the same humate both in composition and alone (65 and 91 µg C g⁻¹). Under conditions of HM contamination at the end of the incubation, the levels of microbiological parameters in HM spiked soil–polymer mixtures did not statistically differ from the uncontaminated control. Every polymer formulation helped to partially restore microbial activity while reducing the toxic effects of HM. In these circumstances, humate from lignite both by itself and in combination with HYPAN performed better. The quality of organic matter in both humates and HYPAN was the primary determinant of the impact of the examined amendments.

Conclusions

Combination of natural humate and synthetic HYPAN stimulated the activity of soil microorganisms, increased their biomass and mitigated the toxicity of heavy metals present in the soil. This allows the use of binary HYPAN-humate formulations to improve the chemical and biological properties of soil and increase its productivity.

Graphical Abstract

Background

This study aimed to evaluate the ensiling characteristics, bacterial community structure, co-occurrence networks, and their predicted functionality and pathogenic risk in high-moisture oat (Avena sativa L.) silage. The oat harvested at heading stage (224 g/kg fresh weight) was spontaneously ensiled in plastic silos (10 L scale). Triplicate silos were opened after 1, 3, 7, 15, 30 and 60 days of fermentation, respectively. The bacterial community structure on day 3 and 60 were investigated using high-throughput sequencing technology, and 16S rRNA-gene predicted functionality and phenotypes were determined by PICRUSt2 and BugBase tools, respectively.

Results

After 60 days, the oat silage exhibited moderate fermentation quality, as indicated by large amounts of acetic acid (~ 50.4 g/kg dry matter (DM)) and lactic acid (~ 55.4 g/kg DM), relatively high pH (~ 4.79), acceptable levels of ammonia nitrogen (~ 75.2 g/kg total nitrogen) and trace amounts of butyric acid (~ 3.36 g/kg DM). Psychrobacter was prevalent in fresh oat, and Enterobacteriaceae and Lactobacillus dominated the bacterial community on day 3 and 60. Ensilage reduced the complexity of bacterial community network at the initial stage of fermentation. The bacterial functional pathways in fresh and ensiled oat are primarily characterized by the metabolism of carbohydrate and amino acid. During ensiling, the elevated pyruvate kinase and 1-phosphofructokinase levels were correlated with the lactic acid production, and the increased levels of 6-phosphogluconate dehydrogenase and ribulose-5-phosphate 3-epimerase may be responsible for the abundant acetic acid contents. Greater (P < 0.01) proportions of “Potentially Pathogenic” were observed in the bacterial community of oat silage compared to fresh oat.

Conclusions

Altogether, the findings indicated that the high-moisture oat silage exhibited moderate fermentation quality, and the potential for microbial contamination and pathogens remained after 60 days of ensiling. Therefore, some effective chemical and microbial additives are recommended to ensure the quality, hygiene, and safety in high-moisture oat silage production.

Graphical Abstract

The approaches of nanoparticles (NPs) usage have been successfully applied to increase the growth and biological activity of aromatic and medicinal plants. In this context, we studied the effects of zinc–aluminum layered double hydroxide (Zn–Al LDH) and magnesium–Al LDH (Mg–Al LDH) NPs on geranium plants. Both LDH NPs were synthesized using the co-precipitation technique and characterized with SEM, FTIR, XRD, and Zeta potential. Using the spray method, Zn–Al LDH and Mg–Al LDH NPs (10 ppm) were used in a factorial experiment with a fully randomized design. Applying LDH NPs increased Mg and Zn content, which boosted plant growth, photosynthetic pigments, and soluble sugar levels. The administration of both LDH NPs results in a constant increase in secondary metabolites such as essential oils (EOs). Monoterpenes such as geraniol (32.7%) and β-citronellol (29.18%) were found to be the main components of the EO. Geranium plants treated with Mg–Al LDH NPs exhibited the highest levels of polyphenols (44.5%), flavonoids (33.5%), and total antioxidant capacity (31.7%). Additionally, LDH NPs had a favorable effect on antioxidant enzyme activity including catalase and peroxidase activities. Overall, Zn–Al LDH and Mg–Al LDH NPs foliar application acted as an elicitor to enhance growth and bioactive metabolite accumulation in geranium plants. Despite these promising results, several challenges remain for the broader application of LDH NPs in agriculture.

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Background

The incorporation of circular economy into agricultural processes is necessary to improve the efficiency of agronomic practices in the future. The biomass of macroalgae as well as humic substances is sustainable options for stimulating the efficient use of nutrients in plants. This study aimed to evaluate the modes of action of a potential plant biostimulant composed of an aqueous extract of Kappaphycus alvarezii seaweed plus fulvic acid (KAF) applied to rice (Oryza sativa L.) leaves. The aqueous extract was obtained from the fresh biomass of the macroalga Kappaphycus alvarezii and the fulvic acid was extracted from a cattle manure vermicompost (FA_VC). Both fractions (K_Alv-sap and FA_VC) were characterized using ¹H NMR. The bioactivity of KAF was evaluated in experiments with four treatments: control (foliar application of water), FA_VC (foliar application of FA_VC), K_Alv-sap (foliar application of seaweed extract), and KAF (foliar application of FA + K_Alv-sap). In rice, the expression of genes related to K⁺ and N transport, plasma membrane H⁺-ATPases, and oxidative stress defense enzymes were evaluated. Metabolites and N, K, and P contents, as well as photosynthetic efficiency and root morphology, were quantified.

Results

The ¹H-NMR spectra showed that KAF is rich in organic fragments such as sugars, nitrogenous, aromatic, and aliphatic compounds in general. Foliar application of KAF resulted in a 7.1% and 19.04% increase in the dry mass of roots and leaves, respectively. These plants had 19% more roots and 11% more total root length. The application of KAF increased in the plant sheaths the N and K contents by up to 50% and 14%, respectively.

Conclusions

The mechanism of action by which KAF triggered these changes seemed to start with an improvement in the photosynthetic efficiency of plants and regulation through increased expression and suppression of genes related to K⁺, N, H⁺-ATPase transporters, and oxidative metabolism. KAF might become a sustainable plant biostimulant that promotes plant growth, development, and defense against abiotic stresses.

Graphical Abstract

Background

Amino acids (AAs) play multiple roles in plant development, and their reorientation is crucial strategy for plants in metabolic adaptation to various abiotic stresses. The incorporation of exogenous CN⁻ into the N fertilization in plants is evident, wherein elevated CO₂ increases utilization and assimilation of biodegradable N-containing pollutants, consequently reduce phytotoxicity. In this study, a hydroponic system was employed to investigate the effects of different nitrogen (N) forms (nitrate: NO₃⁻ and ammonium: NH₄⁺), CO₂ concentrations (ambient at 350 ppm and elevated at 700 ppm), and exogenous cyanide (KCN at 3.0 mg CN/L) on rice plants using metabonomics analysis.

Results

Elevated [CO₂] (700 ppm) significantly enhanced the growth rate of rice seedlings, particularly under NH₄⁺ nutrition combined with CN⁻ treatment, compared to ambient [CO₂] (350 ppm). Under elevated [CO₂] both NO₃⁻ and NH₄⁺-fed plants exhibited significantly higher CN⁻ uptake and assimilation rates, with NH₄⁺-fed plants showing a greater response. Metabolomic analysis revealed distinct alteration in AA profiles, where elevated [CO₂] and exogenous CN⁻ significantly influenced the proportions of the glutamate (Glu) pathway and aspartate (Asp) pathway under both N treatments. Notably, NH₄⁺-fed plants under CN⁻ stress demonstrated a 5.75-fold increase in total AA content in shoots under elevated [CO₂], while NO₃⁻-fed plants CN⁻ stress showed a smaller increase of 1.81-fold. These results suggest that elevated [CO₂] coupled with NH⁴⁺ nutrition optimizes rice metabolic adaptation to CN⁻ stress.

Conclusions

This study highlights the strategic alteration of AA profiles as a key adaptive mechanism in rice plants facing elevated [CO₂] and exogenous CN⁻ stress. These shifts in AA pathways facilitate enhanced nutrient assimilation and stress resilience, offering insights into plant metabolic adaptation under changing environmental conditions.

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Background

Rice blast is a devastating disease caused by Magnaporthe grisea, and it is not well controlled globally. As a Traditional Chinese Medicine, Artemisia argyi has been proven to have inhibitory effects on a variety of phytopathogenic fungi. Here, we used bioactivity-guided isolation method and transcriptomics to clarify the antifungal active compounds in A. argyi and their antifungal mechanisms.

Results

In vitro studies showed that the absolute ethanol extract (AEE) of A. argyi had a strong inhibitory effect on the growth of M. grisea, with a low EC₅₀ value of 1.156 mg/mL, and could cause the destruction of hyphae cell membrane and the leakage of cell contents. To identify the active constituents, we fractionated the AEE using macroporous adsorption resin and silica gel column chromatography. The active fraction (Fr.F-1) was fractionated and had even higher antifungal activity than AEE. The results showed that both AEE and Fr.F-1 could impact primary metabolic pathways and reactive oxygen species homeostasis of M. grisea, decrease the content of reducing sugars and downregulate the expression of genes related to starch and sucrose metabolism. Further fractionation of Fr.F-1 led to the identification of two polymethoxylated flavonoids (eupatilin and 3,5,3ʹ-trihydroxy-7,8,4ʹ-trimethoxyflavone), both of which had antifungal activity and they worked synergistically in Fr.F-1. Finally, we also investigated the effect of AEE, Fr.F-1 and eupatilin on rice blast control. The results showed that AEE, Fr.F-1 and eupatilin application strongly enhanced rice resistance to M. grisea.

Conclusion

In brief, these findings indicate that Fr.F-1 subfraction from A. argyi and its main components polymethoxylated flavonoids confer inhibiting activities to M. grisea. This discovery can effectively alleviate the degradation pressure of A. argyi by-products, promote the healthy development of its industry, and provide new a strategy for the development of new botanical fungicides to control rice blast.

Graphical Abstract

Background

Light, an essential factor in plant development, exerts a significant impact on both primary and secondary metabolism in plants. Althaea officinalis, commonly known as marshmallow, offers versatile applications through its leaves and roots. With a plethora of identified bioactive compounds and their extensive use in food, health, and supplements, it is widely cultivated globally. This study aimed to demonstrate the definitive positive impact of dark and light irradiation on both primary and secondary metabolite production in A. officinalis hairy roots and to elucidate the light-responsive mechanism through integrated metabolome and transcriptome analysis.

Results

When exposed to light, significant changes with a greenish colour shift were observed in 60 metabolites. Multivariate statistical analysis revealed a distinct separation between light- and dark-treated hairy roots, likely attributed to metabolites such as glutamic acid, phenylalanine, catechin hydrate, and chlorophyll. Correspondingly, the pathways significantly impacted included galactose metabolism, alanine, aspartate, and glutamate metabolism, flavone and flavonol biosynthesis, and phenylalanine metabolism. Light-responsive differentially expressed genes associated with pigment and phenylpropanoid biosynthetic pathways were analysed and compared via RNA sequencing. Furthermore, among the light-related transcription factors, including CONSTANS-LIKE and double B-box zinc finger, which are responsible for photomorphogenic modulation, were upregulated. Moreover, light-responsive genes, such as ribulose bisphosphate carboxylase, photosystem II, and chlorophyll A-B binding family protein, were upregulated.

Conclusions

These findings emphasise that exposure of A. officinalis hairy root culture to light conditions is a useful method for enhancing most of the primary and secondary metabolites.

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Nickel (Ni) pollution in soil is a major environmental challenge to global food security necessitating its effective remediation. In this regard using plant growth promoting rhizobacteria (PGPR) and bioorganic fertilizers (BOF) to increase the effectiveness of Ni phytoextraction together with hyper-accumulator plants is an effective strategy. Thus, the aim of this study was to assess how BOF, alone or in combination with Bacillus sp. MN54 (herein after referred to as BS), promotes the growth and detoxifies Ni in Brassica juncea L. under both non-contaminated and Ni-contaminated soil conditions. The experimental design included both non-spiked and Ni-spiked soils (with two Ni concentrations: 50 and 100 mg kg⁻¹), with the addition of BS and BOF at two different application rates (1% and 2%). Results showed that Ni negatively affected the growth attributes and yield of Brassica juncea but the integrated incorporation of BOF and BS significantly improved plant growth and physiological attributes. However, Ni stress increased antioxidant enzyme activities and triggered the production of reactive oxygen species in the plants. Likewise, the highest increases in Ni bioconcentration factor (19.9%, 72.83%, and 74.2%), Ni bioaccumulation concentration (30.6%, 327.4%, and 366.8%), and Ni translocation factor (22.2%, 82%, and 69%) were observed in soils supplemented with 2% BOF and BS under non-contaminated, 50 mg kg⁻¹, and 100 mg kg⁻¹ Ni-stressed conditions, respectively. The enhanced plant growth with BS and BOF under Ni stress suggested that both could efficiently promote Ni phytoextraction and simultaneously improve soil health in Ni-contaminated soil. This highlighted their potential as sustainable soil amendments for remediating Ni-contaminated soils, promoting resilient plant growth and supporting long-term ecosystem recovery.