Chemical and Biological Technologies in Agriculture最新文献

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.

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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.

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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.

Background

Root rot, wilt diseases, and rooting processes have been the major factors that constrain schefflera production. This study focuses on the impact of innovative applications of eco-friendly materials like chitosan nanoparticles loaded with l-proline or indole butyric acid to replace traditional chemical fungicides in controlling root rot and wilt diseases, as well as the vegetative propagation success of leafy stem schefflera cuttings.

Results

Fusarium foeten (strain 1) and Fusarium falciforme (strains 2 and 4) were first identified as root rot and wilt pathogens of schefflera in Egypt based on morphological features and confirmed with molecular analyses. Fusarium foetens (strain 1) and F. falciforme (strain 2) have the most aggressive action, as the infection percentages significantly increased in the pathogenicity test. The disease incidence reached 38.88 and 44.44%, respectively, whereas the disease severity was 18.51 and 26.84%, respectively. Chitosan nanoparticles at a concentration of 25 mg/L were the most effective dose, leading to a significant reduction in disease incidence to 25.00%, disease severity to 4.17%, and playing a vital role in activating plant defense, which correlates well with improved growth characteristics. The novel strategy of L-proline loaded on chitosan nanoparticles (LP-CSNPs) application occupied the first rank at protective influence against root rot and wilt disease-induced oxidative stress, signaling a defensive function that was freelance verified. L-proline loaded on chitosan nanoparticles (LP-CSNPs) at 0.125–0.25 g/L had a significant impact on reducing the incidence and severity of root rot and wilt diseases, as well as improving photosynthetic pigments and free radical scavenging activities, which included strengthening plant defense and further validating the findings from the biochemical trait analysis. The TT biplot graph was an influential statistical tool to study the impacts of treatments on schefflera production and its attributes and to discover the interrelationships among them.

Conclusions

Applying LP-CSNPs is one of the best techniques to manage schefflera root rot and wilt diseases, since it can be utilized as a growth stimulator and defense activator with sustainable increased efficiency.

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Background

Phytoremediation is considered to have great development potential to deal with soil Cd contamination, and assisted measures are necessary to improve the efficiency of Cd extraction from soil by hyperaccumulator plants. Based on this, a pot experiment was conducted to determine the growth indices, physiological indices, Cd content of Solanum nigrum L. and soil bacterial community under single and combined application of earthworm and organic wastes [chili straw and spent mushroom substrate (SMS)].

Results

Pot experiments revealed that adding earthworms, chili straw, or SMS alone did not affect the growth of S. nigrum. However, the combination of earthworms + chili straw and earthworms + SMS, significantly increased the total dry weight of S. nigrum by 20.94% and 74.69% compared to the control. The chlorophyll content of S. nigrum in the treatment groups with earthworms, SMS, and earthworms + SMS was also significantly higher than that in the control. Meanwhile, adding earthworms and organic wastes also reduced the malondialdehyde content in the leaves of S. nigrum and increased the activity of superoxide dismutase and peroxidase. In addition, applying earthworm + chili straw and earthworm + SMS also increased the availability of Cd in the soil, promoted the absorption of Cd by S. nigrum, and significantly increased its total extraction amount of Cd by 41.55% and 92.83%, respectively. The diversity of soil bacterial communities increased when earthworms and organic wastes coexisted. Adding earthworms and organic wastes also increased the relative abundance of Verrucomicrobia at the phylum level and of Sphingomonas, Ohtaekwangia, Saccharibacteria_genera_incertae_sedis, and Aridibacter at the genus level in the soil. At the same time, this process reduces the relative abundance of Proteobacteria and Firmicutes at the phylum level and Devosia and Bacillus at the genus level.

Conclusions

The combined application of earthworms and SMS enhanced phytoextraction of Cd-contaminated soil by S. nigrum. It also improved soil nutrient conditions and reduced external environmental stress on bacteria, increasing their diversity and restructuring the community structure, which was conducive to forming a good soil microecological environment. The results of this study can provide a scientific basis for the treatment of Cd contaminated soil, but field experiments need to be conducted for verification and optimization before practical application in the future.

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Background

Bacterial auxin production is a mechanism that promotes plant growth. However, it can also be linked to deleterious rhizobacteria and plant-pathogenic bacteria. High levels of auxins have the potential to impede plant growth. Additionally, certain environmental factors can enhance auxin activity and impact the activity of plant growth-promoting rhizobacteria (PGPR).

Results

In this work, we boarded how the auxin-like effect in the soil–plant system modulates the plant growth-promoting activity of Lysinibacillus pinottii sp. nov. PB211. The effect of humified organic matter (HOM) soil was simulated with humic acids (HA) coming from vermicompost; the spectral configuration (¹³C-CP-TOSS-NMR and FTIR) and coleoptile elongation test indicated its bioactivity. Cucumber exhibits a PGP effect of PB211 and HA at a lower concentration compared to corn. This disparity agrees with the differential sensitivity to auxins of both plant models. Monocot plants, such as corn, generally exhibit greater resistance to exogenous auxin activity compared to eudicot plants, such as cucumber. The presence of HA in the growth substrate (sand) is found to modulate the PGPR activity of PB211, resulting in a loss of PGPR activity.

Conclusions

The findings highlight the importance of considering the cumulative auxin-like effects in the soil–plant system when utilizing bacterial inoculants for plant growth promotion in agriculture.

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Background

The polyphagous notorious pest, black cutworm, Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae), cause significant production losses due to its distinctive feeding and hiding behavior, making it particularly challenging to control it with conventional methods. Therefore, sustainable agriculture demands more effective and environmentally safe pest control solutions. This study aimed to investigate the toxicity of two insecticide alternatives, the entomopathogenic fungus (EPF) Beauveria bassiana and Solanum lycopersicum extract (Tomato plant crude extract, TPCE), using two bioassay methods: the poisoned bait method and the leaf dipping method. In addition, the impact of these biological tools on larval development and protein profiles was evaluated.

Results

The bait application of both tested materials exhibited higher toxicity than the leaf dipping method, as indicated by the toxicity index. The LC₅₀ values for B. bassiana were 1.6 × 10⁸ and 1.8 × 10⁶ conidia ml⁻¹ using the leaf dipping method and poisoned baits method, respectively. For TPCE, the LC₅₀ values were 4.35 and 1.51 mg ml⁻¹ for the same methods, respectively. In addition, sublethal concentrations of both materials altered the larval and pupal durations. B. bassiana significantly reduced the concentration of larval hemolymph protein. A maximum of 12 protein bands in the control sample, with molecular weights (Mw) ranging between 35 and 120 kDa, were detected by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE). In B. bassiana-treated larvae, ten bands were detected with Mw ranging from 35 to 120 kDa. At least seven bands were detected in TPCE-treated larvae, with Mw ranging from 35 to 97 kDa.

Conclusions

The findings of this study can be integrated into management programs for A. ipsilon. In addition, the availability of B. bassiana and TPCE in Egypt and their cost-effectiveness as insecticide alternatives support their use in the management programs of this critical pest. These methods are particularly effective when applied in bait form.

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