Chemical and Biological Technologies in Agriculture最新文献

Background

Antimicrobial peptides (AMPs) have emerged as a potential novel class of antimicrobial agents due to their broad microbial targeting and low resistance risks. Although AMPs have limited applications in agriculture, their potential to replace chemical pesticides could address food security and environmental concerns. Members of Bacillus sp., abundant in soil and plant microbiomes, are recognized as important sources of AMPs for their resistance and strong antimicrobial properties, making them ideal candidates for biocontrol in sustainable agriculture. To harness this potential, this study employed deep learning models to predict AMPs derived from Bacillus genomes, aiming to identify candidates with high activity against phytopathogens. Subsequently, the antimicrobial efficacy of selected candidate AMPs was experimentally validated.

Results

More than 6700 Bacillus genomes were collected to identify a broad range of short peptides (10–100 amino acids), which were analyzed using advanced deep learning models, including BERT, Mamba, CNN-LSTM, and CNN-Attention. These models demonstrated enhanced predictive accuracy and reliability over existing methods, and resulted in 4,993,389 potential AMPs from Bacillus genomes. Among these AMPs, two high-confidence AMPs (cAMP_1 and cAMP_2) were selected by cross-validation, and their structural stability and activity were evaluated and verified by molecular dynamics simulations and experimental assays, respectively. Both of them exhibited antimicrobial activity against Escherichia coli, Staphylococcus aureus, and various common agricultural fungal and bacterial pathogens.

Conclusions

This high-throughput deep learning pipeline successfully uncovered novel AMPs from Bacillus genomes, which underscored the efficiency of deep learning models in identifying functional peptides. This approach could accelerate the discovery of potential AMPs for biocontrol applications in plant disease management, contributing to sustainable agriculture and reduced dependency on traditional antibiotics.

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Siraitia grosvenorii, commonly known as Luo Han Guo, is a medicinal and edible plant whose flowers contain bioactive polysaccharides with underexplored therapeutic potential. This study isolated a novel polysaccharide fraction (SGFP-2) from Siraitia grosvenorii flowers through DEAE-Crystarose Fast Flow chromatography. Structural analysis revealed SGFP-2 is a heteropolysaccharide with average molecular weight of 1.67 × 10⁵ Da and composed of Rha, Glc, Gal, GlcA, GalA, Man, and Ara with a molar ratio of 8.17:1.54:60.06:3.41:5.37:3.54:15.44. Methylation analysis identified dominant glycosidic linkages of SGFP-2 as → 6)-Galp-(1 → (30.42%), Galp-(1 → (22.69%), Araf-(1 → (18.29%), Rhap-(1 → (8.70%), → 3,6)-Galp-(1 → (8.54%). Scanning electron microscopy and Congo red staining results showed that the network structure of SGFP-2 was lamellar without trihelix conformation. In vitro experiments have revealed that SGFP-2 possesses lipid-binding capacity, bile salt adsorption properties, and potent inhibitory activity against crucial enzymes involved in glucose-lipid metabolism, specifically pancreatic lipase, cholesterol esterase, α-amylase, and α-glucosidase. These findings suggest that SGFP-2 demonstrates potential hypolipidemic and hypoglycemic effects in vitro. This study provides preliminary evidence to support further development and utilization of Siraitia grosvenorii flower polysaccharides.

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Background

Sweet sorghum (Sorghum bicolor (L.) Moench) is a popular forage crop in arid and semi-arid areas due to its high drought tolerance, rapid growth, and low production costs. In addition, sweet sorghum, has relatively specific ensiling characteristics because of its high moisture content and sufficient amount of water soluble carbohydrates. Therefore, it is crucial to investigate the raw material characteristics and exogenous additive pretreatment for the regulation of silage quality. This study aimed to evaluate the effects of Lactobacillus plantarum (LP) and cellulase (CEL) on the fermentation profile, carbohydrate composition, in vitro rumen fermentation and microbiota communities of sweet sorghum silages with two different raw material characteristics (fresh sweet sorghum material (MC1); sweet sorghum material wilted outdoors for 6 h after chopping (MC2)).

Results

In this study, the sweet sorghum treatments were: control (without additives), LP, CEL, or a combination of LP and CEL (LP_CEL). All treated sweet sorghum samples were ensiled for 30 d. A higher content of lactic acid, propionic acid, D-fructose, glucose, sucrose and a lower content of structural carbohydrates were observed in MC1 silage than in MC2 silage. In MC2 silage, the addition of CEL or LP_CEL decreased the content of structural carbohydrates, while it increased the content of D-fructose, glucose, D-arabinose, xylitol, maltose and trehalose (P < 0.05). The in vitro gas production at 48 h was greater in MC1 silage than in MC2 silage, and the addition of CEL or LP_CEL increased the in vitro dry matter digestibility in MC2 silage (P < 0.05). After 30 d of ensiling, disaccharides such as sucrose, maltose and alginate were almost entirely utilized by the microorganisms, while more-consumed monosaccharides included D-fructose, glucose and L-rhamnose. Lactobacillus was the dominant genus (> 80% relative abundance) in all silage samples.

Conclusions

Raw material characteristics determine carbohydrate composition, in vitro digestibility, and microbial community of sweet sorghum silage. For wilted sweet sorghum with relatively low moisture content, pretreatment with CEL or LP_CEL reduced the structural carbohydrate content, increased the nonstructural carbohydrate content, and improved the digestibility of the silage. However, additives had no obvious impact on enhancing the fermentation quality of sweet sorghum silage for two raw material characteristics.

Graphical abstract

NIR spectroscopy-based detection technology is an analytical methodology that utilises the absorption, reflection, and transmission properties of near-infrared light when interacting with a variety of substances. The technique facilitates the assessment of the composition and characteristics of the materials being analysed. Notably, NIR spectroscopy is characterised by its nondestructive nature, rapid execution, high sensitivity, ease of operation, and efficiency in analysis. In recent years, this technology has been widely applied and expanded in many fields, such as food analysis, biology, and medicine. Root crops, including but not limited to potatoes, cassava, yams, and sweet potatoes, are vital nutritional components of human diets and also serve as critical raw materials in food processing and industrial applications. The significance of these crops is underscored by their impact on consumer health and the economic viability of enterprises, thereby highlighting the importance of effective detection methods for these crops. NIR spectroscopy detection technology is capable of conducting thorough evaluations of both the internal qualities (e.g., starch, protein, sugars, and soluble solids) and the external qualities (e.g., appearance, morphology, pest infestations, and diseases) of root crops. In comparison with alternative spectroscopic techniques, NIR spectroscopy offers a more straightforward approach for the detection and analysis of root crop samples, whilst preserving the integrity of the samples. This emphasises the significant potential of NIR spectroscopy for real-time online monitoring of root crops. The present paper provides a concise overview of the principles underlying NIR spectroscopy detection technology and synthesises research findings regarding its application in the quality assessment of root crops. It emphasises recent advancements in the field, particularly concerning sample pretreatment, spectral collection and processing, and model development. The discussion further encompasses the advantages and limitations of NIR spectroscopy technology, along with the primary challenges encountered in its practical applications and prospects for future development.

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Aims

Soil amendments play a pivotal role in revitalizing soil ecosystems degraded by continuous intensive farming practices. However, existing research primarily focuses on chemical or biological amendments, overlooking the potential of plant-derived fermentation products. The influence of plant fermentation products on diverse soil functions and their underlying connections with soil microbial communities remains elusive. This study delves into the effects of various plant fermentation products as innovative amendments on transplanted soil.

Methods

We evaluated soil functions encompassing ginseng yield and quality, nutrient cycling processes, soil enzymatic activities crucial for primary production, and physicochemical properties.

Results

Our findings reveal that plant fermentation products effectively enhance soil functions, with XS (fine Manchurian wildginger and Shiso) exhibiting the most pronounced impact on restoring soil fertility compared to untreated aged ginseng soil. Furthermore, application of these products altered bacterial and fungal community compositions, marked by increased relative abundances of dominant bacterial phyla (e.g., Actinobacteria and Proteobacteria) and fungal phyla (e.g., Ascomycota and Basidiomycota). Notably, bacterial networks exhibited greater complexity post-treatment, suggesting a more responsive nature to environmental changes compared to fungi. Bacterial networks were dominated by positive interactions, significantly stronger than those in fungal networks. Functional predictions indicate that treatments involving plant fermentation products modified the metabolic capabilities of soil fungal communities. Additionally, these treatments significantly reduced plant disease incidence associated with transplantation, with XS being the most effective.

Conclusions

In conclusion, our results demonstrate that plant fermentation products foster stronger intra- and inter-microbial interactions, thereby enhancing soil ecosystem multifunctionality and promoting sustainable agriculture.

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Among the fungal diseases, Fusarium head blight (FHB), caused by Fusarium graminearum, is one of the most destructive disease affecting wheat. This pathogen poses significant threats to global wheat production, leading to substantial yield losses and contaminating grains with harmful mycotoxins. The chemical control of FHB has become increasingly challenging due to the rise of pathogen resistance, environmental concerns, and the effects of climate change. This review introduces a novel approach to disease management through spray-induced gene silencing (SIGS), a cutting-edge technology that uses double-stranded RNA (dsRNA) to silence critical genes in both the fungus and the host plant. This silencing reduces pathogen virulence and enhances plant resilience. A key innovation is the integration of nanotechnology to improve the delivery of dsRNA, addressing challenges related to stability, cellular uptake, and targeting efficiency in field conditions. Nanocarriers have revolutionized dsRNA delivery by improving its encapsulation efficiency, precision, and stability, compared to traditional methods. Advances in cost-effective dsRNA production, particularly through microbial expression systems, enable scalable and sustainable implementation of this technology. This review emphasizes the potential of nanocarrier systems in precision agriculture and highlights their role in replacing harmful chemical treatments with RNA interference (RNAi)-based solutions. RNAi-based approaches not only reduce reliance on synthetic chemicals, but also promote environmental sustainability by addressing fungicide resistance. However, challenges remain in large-scale field application, cost-effectiveness, and regulatory approval processes. Overcoming these hurdles will be crucial to unlocking the full potential of this technology. In conclusion, the combination of nanotechnology and SIGS-based dsRNA delivery offers a groundbreaking approach to managing Fusarium infections in wheat. This innovative strategy has the potential to minimize environmental impacts while enhancing global food security, paving the way for a more sustainable and resilient agricultural future.

Graphical Abstract

Background

This study addresses the critical issue of Fusarium wilt in tomatoes, caused by Fusarium oxysporum f. sp. lycopersici (FOL), a severe fungal pathogen responsible for global yield losses. Conventional control measures, such as resistant crop varieties and chemical fungicides, have limitations due to environmental concerns and the risk of pathogen resistance. As a sustainable alternative, this study aims to explore the biocontrol potential of the bacterial strain Sh-17, focusing on its lipopeptides (LPs) to effectively suppress FOL.

Results

This study demonstrated the antifungal capability of the Sh-17 strain, obtained from a tomato field, against FOL. Through 16S rDNA gene sequence analysis and phenotypic evaluation, Sh-17 was identified as Bacillus subtilis Sh-17. During the disease control assay using in vitro petri dishes, Sh-17 showed promising plant growth-promoting and disease-control capabilities in seedlings when tomato seeds were inoculated with both Sh-17 and FOL. Subsequently, the lipopeptide extract derived from Sh-17 showed strong antifungal properties in a dose-dependent manner, with complete inhibition of FOL at a concentration of 3500 µg mL⁻¹. Furthermore, it was observed that LPs decreased the amount of ergosterol, which affects the stability and general structure of the plasma membrane. The genomic DNA of Sh-17 was subjected to PCR screening, which revealed the presence of genes responsible for the biosynthesis of antifungal LPs. Furthermore, LC–MS analysis identified distinct LPs, such as surfactins, fengycin, iturins, bacilysin, and bacillomycin derivatives in the crude LPs extract of Sh-17. Moreover, microscopic analyses (fluorescent/TEM) demonstrated morphological abnormalities and even death of the hyphae and spores of the phytopathogen upon its interaction with LPs.

Conclusions

B. subtilis Sh-17 exhibits strong antifungal properties against FOL and supports seedlings health by protecting them from pathogen infestation. The LPs produced by Sh-17 inhibit FOL growth in a dose-dependent manner by disrupting the pathogen’s cellular structures and proved to be an effective biocontrol agent against Fusarium wilt in tomatoes.

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Cottonseed kernel (CK) contains high contents of protein and lipids and can be used as a protein feed ingredient. However, the application of CK in animal feed is limited due to the presence of free gossypol. High levels of free gossypol is toxic to animals by affecting protein digestion, causing liver and kidney damage, and impacting growth and reproduction. Microbial fermentation is an effective processing approach to reduce gossypol, improve nutritional value and produce functional peptides of cottonseed by-product. The objective of this study was to evaluate the influence of microbial fermentation on the free gossypol, nutrients and flavor substances of CK. Then the structure, water and oil holding capacity and in vitro antioxidant activity of derived peptide were examined. Fermentation significantly decreased free gossypol content from 0.12 mg/kg to not detected, while increased the contents of crude protein, ether extract, water-soluble protein contents and peptide yields by 5.11%, 9.42%, 40.98% and 39.79%, respectively. Compared with unfermented CK (UCK), the total amino acids, palmitic, oleic acid and linoleic acid contents of fermented CK (FCK) were significantly higher by 114.72%, 24.31%, 14.34% and 14.25%, respectively. Meanwhile, the relative contents of alcohols, aldehydes, esters in FCK were increased by 10.85-fold, 8.75-fold, 8.25-fold compared with UCK. In addition, the derived peptides from FCK (FCKP) possessed higher water and oil holding capacities compared to derived peptides from UCK (UCKP), by 7.01 fold and 22.95%, respectively. In vitro antioxidant assay indicated that FCKP exhibited stronger DPPH, hydroxyl radical scavenging activities and reducing power. In conclusion, microbial fermentation remarkably improved the nutritional value and flavor substances of CK, and derived CK peptide with antioxidant activity.

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The risks posed by conventional herbicides have driven research toward environmentally friendly alternatives for sustainable agriculture. We synthesized silver nanoparticles (AgNPs) using aqueous extracts from the allelopathic plant Nelumbo nucifera Gaertn. (lotus) leaves, and their herbicidal activities were investigated against farmland weeds. The lotus-assisted AgNPs were characterized using ultraviolet–visible (UV–Vis) spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The surface plasmon resonance (SPR) band at 459 nm observed from the UV–Vis spectrum confirmed the successful synthesis of AgNPs. The hydrodynamic diameter of the AgNPs, as determined by the dynamic light scattering (DLS) measurement, was 105.1 nm, with a polydispersity index of 0.196. XRD results confirmed the synthesized AgNPs were proven to be crystalline with an average crystallite size of 18.62 nm. TEM analyses revealed that the AgNPs exhibited a spherical morphology with an average particle size of 12.87 nm. The herbicidal activities against Bidens pilosa L. of these lotus-mediated AgNPs were tested using both the Petri dish method and the soil irrigation method. The plant-derived AgNPs demonstrated a greater inhibitory effect on the seed germination and seedling growth of B. pilosa than the lotus extract. The results from herbicidal tests demonstrated that the synergetic herbicidal activity was realized after combining lotus extract with AgNPs. This study provided a new alternative to synthesize AgNPs by allelopathic plants, which could be used as botanical nanoherbicides for weed management in sustainable agriculture.

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Background

Drying has been considered a preservation technique for reducing water activity, preventing microbial growth, and preserving the quality of aromatic and medicinal plants. Therefore, an understanding of the changes in plant metabolisms due to dehydration during drying and the resulting changes in the active components of medicinal crops is required. Centella asiatica (L.) Urban is one of the important medicinal plant for consumption or medicinal purposes with its four most abundant triterpenoids, including two sapogenins (asiatic acid, AA; madecassic acid, MS) and saponins (asiaticoside, AS; madecassoside, MS). This study investigated the effects of the rate of dehydration on C. asiatica using a metabolic approach and identified the proper drying time to obtain the highest active components.

Results

In fresh samples (0-h drying condition), the highest AA content and TCA-related components (citrate, glutamate, and aspartate) levels were observed. As drying progressed, even minimal drying (6 h) induced metabolic changes by suppressing photosynthesis. With extended drying time, a significant time-dependent increase in amino acid production was observed. While amino acid accumulation progressed, an increase in MA content was observed at 12 h of drying along with an increase in CabAS gene expression levels. Subsequently, representative stress-related amino acids (GABA and proline) levels rose over time, peaking at 24 and 48 h of drying, respectively. At 48 h of drying, when the moisture in the C. asiatica had disappeared, an increased level of CaAS expression (involved in biosynthesis of α-amyrin, the precursor of AA and MA) was observed. At extreme dehydration (96 h of drying), increased levels of CaGT expression (involved in the glycosylation of AA and MA to produce AS and MS) were recorded. Consequently, these elevated biosynthesis gene expression levels resulted in increased saponins, including AS and MS content. However, beyond 96 h of drying, all the metabolites underwent degradation.

Conclusions

This study highlights that metabolic responses during drying significantly alter centellosides by stimulating diverse metabolic pathways. Optimizing the drying period would maximize active components (MS and AS) in C. asiatica, thereby enhancing its pharmaceutical value.

Graphical Abstract