Chemical and Biological Technologies in Agriculture最新文献

Entomopathogenic nematodes (EPNs) belonging to the genera Heterorhabditis and Steinernema are mutualistically associated with bacteria in the genera Photorhabdus and Xenorhabdus. The complexes of EPNs and their bacterial symbionts infect and kill a wide range of soil-dwelling insects that are harmful to crops. Given this advantage, these complexes have been primarily developed as a biocontrol agent to replace chemical pesticides on crops when society calls for healthy agriculture. This review examined recent advances in mutualistic bacteria of EPNs, secondary metabolites, and the mechanisms underpinning the interactions between mutualistic bacteria and insect hosts, as well as their potential application as a biocontrol agent. Based on this, new insights were provided to address the current issues that restrict the exploration of such biological agents, informing future research and guiding the development of biocontrol strategies for sustainable agriculture.

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Background

Saline-alkali stress severely impacts global crop productivity, while basic leucine zipper (bZIP) transcription factors (TFs) are known regulators of abiotic stress responses, the specific mechanisms of StbZIP1 in potato saline-alkaline tolerance remains unclear.

Methods

We cloned StbZIP1 from tetraploid potato ‘Favorita’, analyzed its sequence characteristics, and generated overexpression lines. StbZIP1-overexpressing (OE) and wild-type (WT) plants were subjected to saline-alkaline stress (NaCl: NaHCO₃ = 1:1) to assess physiological and molecular responses.

Results

StbZIP1 encodes a 16.61 kDa protein with conserved bZIP domains. Secondary structure prediction revealed that the protein comprises 55.48% α-helix and 44.52% random coil, consistent with the structural characteristics of typical bZIP family features. Physicochemical characterization revealed StbZIP1 was a highly hydrophilic protein (GRAVY index: −0.882) with no transmembrane region, and it harbors 27 predicted phosphorylation sites. Subcellular localization analysis using GFP-tagged StbZIP1 via confocal microscopy confirmed its exclusive nuclear localization, classifying it as a nuclear-targeted transcription factor. Under saline-alkaline stress, WT plants displayed severe wilting and complete desiccation of lower leaves, whereas StbZIP1-OE plants exhibited delayed wilting, no death and retained greener apical leaves. Quantitative analysis revealed that StbZIP1-OE plants showed a 33%–50% increase in chlorophyll content compared to WT (p < 0.01). Notably, StbZIP1-OE plants exhibited a more pronounced increase in Pro content (28% ~ 46%) higher than WT, while their MDA content was significantly reduced compared to WT. Furthermore, the activities of antioxidant enzymes (SOD, POD, and APX) were markedly elevated in StbZIP1-OE plants, showing increases of 81% ~ 100%, 81% ~ 104%, and 20% ~ 43%, respectively, relative to WT. Analysis of stress-related gene expression showed that after 12 d of saline-alkaline stress, the OE plants exhibited significantly increased expression of all six genes (StNCED, StRD29B, StABI5, StP5CS, StSOD, and StCAT) compared with WT (p < 0.05).

Conclusions

StbZIP1 positively regulates saline-alkaline tolerance by enhancing antioxidant capacity, providing a reference for the further cultivation of new stress-resistant potatoes.

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The detection of melamine in milk has consistently been a crucial issue in food safety. Near-infrared spectroscopy is widely used for rapid, non-destructive quantitative analysis and adulteration detection in dairy products, as evidenced by its application in detecting components, such as moisture, fat, and protein, and identifying adulterants, such as water and starch. Despite advancements in qualitative and quantitative models using near-infrared spectroscopy for melamine detection in milk, such as those employing discriminant analysis and partial least squares methods, the technique still faces challenges due to its inherent low sensitivity and high detection limits. This paper proposes a novel method for the detection of melamine in milk based on surface-enhanced near-infrared absorption (SENIRA) spectroscopy with gold nanoparticles. Gold nanospheres were successfully fabricated as substrates for enhancing near-infrared spectroscopy signals, leveraging their unique quantum confinement effects and interactions with light. Utilizing a wavelength range of 900 ~ 1700 nm and various chemometric methods, the concentration of melamine in milk, ranging from 0.0001 to 0.1 mg/mL, was quantified. The modelling effects were found to be favourable, with a calibration correlation coefficient (R_c²) of 0.9853, a prediction correlation coefficient (R_p²) of 0.9837, and a root mean square error of calibration (RMSEC) of 0.0059, the root mean square error of prediction (RMSEP) was 0.0066, the relative prediction deviation (RPD) was 5.3940, and the average recovery rate was calculated to be 117%. The combination of a high correlation coefficient a low prediction error, a high RPD value, and acceptable recovery rates suggests that the established model is robust and has competent predictive performance. Furthermore, experiments have demonstrated the feasibility of using SENIRA in conjunction with chemometrics for the determination of melamine content in milk, a process that aligns with the successful application of HPLC and NIR spectroscopy techniques as detailed in recent studies.

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Xanthomonas oryzae pv. oryzae (Xoo), the causative agent of bacterial leaf blight (BLB) in rice, poses significant threats to global crop productivity. To develop eco-friendly alternatives to chemical pesticides, this study synthesized zinc (Zn) and silver (Ag) nanoparticles (NPs) using Citrus maxima and Citrus sinensis extracts. NPs were characterized via UV–vis spectroscopy (peaks at 349 nm and 441 nm), FT-IR (identifying capping agents), and electron microscopy (spherical NPs, 8–56 nm). Antimicrobial assays revealed potent activity against Xoo, with Ag Nps exhibiting larger inhibition zones (31.32 mm) than ZnO NPs (19.31 mm). In vivo trials demonstrated infection reductions of 63.39% (Ag Nps) and 52.76% (Zn NPs), comparable to conventional pesticides. NPs enhanced superoxide dismutase (SOD) and peroxidase (POD) activities, thereby reducing ROS accumulation. Soil analysis indicated treatment-specific heavy metal dynamics: Zn NPs elevated Zn and Al levels. Microbial communities shifted under NP exposure; Flavisolibacter, Sphingomonas, and Candidatus Koribacter abundances varied significantly, distinguishing NP treatments from pesticides. Metabolomic profiling highlighted Ag Nps -induced upregulation of fatty acid and monoterpenoid biosynthesis pathways, suggesting targeted metabolic responses. While both NPs effectively suppressed BLB, Ag Nps showed superior antimicrobial performance, whereas Zn NPs influenced soil nutrient profiles. These findings underscore the potential of green-synthesized NPs as sustainable alternatives for BLB management, balancing disease control with minimal adverse effects on plant physiology and soil ecosystems. Further research is warranted to optimize NP dosages and assess long-term impacts on soil health.

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Background

Quinoline, an important nitrogen-containing heterocycle, is frequently found in both natural and synthetic compounds. Numerous quinoline derivatives have been developed as commercial pharmaceuticals and pesticides. Due to quinoline derivatives having exhibited various bioactivities, this research aims to investigate novel quinolin-8-amine derivatives as potential antifungal agents. Elucidating the structure–activity relationships (SAR) provides insights to facilitate the discovery of new agrochemicals.

Results

A series of quinolin-8-amine derivatives were designed, synthesized, and structurally characterized by nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectroscopy (HRMS). Single-crystal X-ray diffraction analysis confirmed the molecular architecture of compound 3n (4-chloro-N-(4-fluorophenyl)-2,3-dimethylquinolin-8-amine). Biological evaluation revealed several synthesized derivatives exhibited fungicidal activity against ten phytopathogenic fungi. Structural analysis of compound 3n revealed two distinct intermolecular hydrogen-bonding motifs: N–H···Cl and C–H···Cl interactions. Hirshfeld surface analysis identified H···H (37.0%) and C···H (12.2%) contacts as the major intermolecular interactions, while energy framework calculations revealed their respective contributions to crystal packing stability. Computational investigations including energy framework analysis, and density functional theory (DFT) calculations consistently emphasized the critical role of the quinoline scaffold in the antifungal activity.

Conclusions

This study provides an improved understanding of the SAR of quinoline-based fungicides, which is valuable for synthesizing novel quinoline derivatives and discovering more potent quinoline-based fungicides.

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Sinorhizobium sp. enhances plant vitality and stress resilience and improves soil structure. Underscoring their significance as agriculturally important bioagents for increased agricultural productivity requires understanding their taxonomic and functional relationships and the genetic foundations and pathways that drive plant growth-promoting traits. Genome sequencing, comparative genomics, functional annotation, and hybrid genome assemblies can achieve these. Comparative genomic analyses revealed a close relationship between the studied strains and Sinorhizobium meliloti and Sinorhizobium kummerowiae, which was further supported by phylogenomic, ANI, AAI, and dDDH analyses. Gene family cluster analysis identified 5999 gene families in the FRNB45 strain, 6116 in the FRNB101 strain, and 5996 in the FRNB126 strain. Functional genomic analysis identified several biosynthetic gene clusters (BGCs) related to secondary metabolite production, including polyketides, non-ribosomal peptides (NRPs), and siderophores, highlighting the metabolic versatility of these strains. KEGG pathway analysis confirmed the presence of nitrogen fixation and phosphate solubilization pathways, genes associated with the synthesis of indole-3-acetic acid (IAA), and siderophores. These findings support the potential application of FRNB45, FRNB101, and FRNB126 as plant growth-promoting rhizobacteria (PGPR), particularly suited for diverse climatic conditions and high-altitude ecosystems. However, further experimental validation is required to confirm their efficacy and consistency under field conditions.

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Background

The health of the hindgut in beef cattle plays a crucial role in their growth and overall health. Oregano essential oil (OEO) has gained attention as a potential alternative to antibiotics due to its various beneficial properties such as antibacterial and anti-inflammatory effects. However, its specific impacts on cecal health in beef cattle and its underlying mechanisms are yet to be fully understood. This study aimed to investigate the effects of OEO supplementation on basal immune status, intestinal barrier integrity-related gene expression, microbiota, and their metabolites in the cecum of beef cattle, thus to better understand its potential mechanism.

Results

Twenty-seven steers (initial body weigh 270.47 ± 16.26 kg) were randomly assigned to three groups with nine replicates each in a 390-day trial. Steers were fed with basal diet (CON), basal diet supplemented with 130 mg/d OEO (LOE), and basal diet with 260 mg/d OEO (HOE). Results showed that dietary HOE supplementation significantly increased the growth performance (average daily gain and final body weight) (P < 0.05). Compared to CON group, both LOE and HOE groups showed reduced levels of interleukin (IL)-1β, IL-2, and tumor necrosis factor α (TNF-α) (P < 0.05), while only HOE decreased IL-6 and increased IL-4 (P < 0.05). Moreover, HOE supplementation upregulated the intestinal tight junction proteins (ZO-1 and Claudin-1) gene expression (P < 0.05). The HOE group exhibited a significant increase in the relative abundances of cecal beneficial bacteria (e.g., Bacillus, Lactobacillus, and Lactococcus, P < 0.05). Furthermore, HOE supplementation increased the concentrations of butyrate in cecal short-chain fatty acids (P < 0.05).

Conclusion

HOE supplementation has the potential to regulate cecal barrier homeostasis, the microbiota and its derived metabolites, improve basal immune status, and ultimately benefit the health and performance of steers.

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Nitric oxide (NO) and salicylic acid (SA) are recognized for their ability to mitigate cadmium (Cd) stress, yet their roles in facilitating plant post-stress recovery after Cd exposure remain poorly understood. This study showed that birch seedlings exposed to 8 and 40 mg kg⁻¹ Cd for 15 and 30 days displayed significant dry weight reduction, elevated reactive nitrogen species (RNS) and reactive oxygen species (ROS) levels, and increased lupeol accumulation compared to controls. After 15 days of 40 mg kg⁻¹ Cd treatment, the exogenous supplement of the NO donor sodium nitroprusside (SNP) or SA effectively alleviated growth inhibition while reducing ROS levels and ROS/RNS ratios by 35.82–149.31% (SNP) and 33.12–147.53% (SA), concurrently enhancing lupeol content by 28.33–54.29% (SNP) and 19.59–80.01% (SA) and upregulating BpLUS2 (lupeol synthase) expression in the leaves, stems, and roots of the seedlings. Yeast expressing BpLUS2 (pYES2-BpLUS2) exhibited 32.89% higher lupeol production and 660.00% greater growth under Cd stress than controls. Furthermore, 1 and 3 μmol L⁻¹ exogenous lupeol increased fresh weight by 62.45% and 101.20% in Cd-stressed birch calli. Collectively, these findings demonstrate that SNP or SA supplementation promotes post-stress recovery in birch seedlings under Cd stress, highlighting the potential role of lupeol in mitigating Cd-induced stress.

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Serbian autochthonous cabbage cv. Futoški is highly susceptible to the plant pathogenic bacterium Xanthomonas campestris pv. campestris, the causal agent of black rot, leading to significant economic losses. This study aimed to isolate indigenous Bacillus spp. and Pseudomonas spp. strains with beneficial traits for biocontrol of black rot. From a total of 115 potential antagonistic strains, four (coded as P-FC 55, RD-FC 88, R-FC 102, And R-FC 114) identified as species Bacillus velezensis were selected as candidates based on strong in vitro antagonistic activity, both as whole cultures and cell-free supernatants, against the most virulent X. campestris pv. campestris strain (XcFC 231) identified in this study. No statistically significant differences were observed between the efficacy of whole cultures and supernatants of biocontrol candidates. Preventive inoculation approaches (seed and foliar) of biocontrol candidates consistently outperformed curative treatments across all strains, highlighting their potential as preferred application strategies. The most effective B. velezensis strain was RD-FC 88, applied in the form of a whole culture during preventive foliar application, achieving 93.86% disease suppression, surpassing copper oxychloride (89.26%) under the same conditions. Chemical profiling (GC/MS and UHPLC–QToF MS) of ethyl acetate extracts revealed the presence of a wide range of antimicrobial organic compounds (e.g., 2,3-butanediol, urea, succinic acid, thymine, phenylalanine, 9H-purin-6-ol) and lipopeptides (surfactins C₁₂–C₁₇), which may be contributing factors to the biocontrol activity of the strains. Next to the surfactins, molecular screening for the presence of genes encoding the production of lipopeptides with antimicrobial activity indicated the potential of strains to produce bacillomycin D and iturins (except R-FC 114) under certain growing conditions. Preventive application (seed and foliar) of biocontrol candidate strains led to an increase in epidermal flavonoid and chlorophyll content, while the opposite trend was observed in curative treatments. The results of this study highlight the strong potential of the B. velezensis strains P-FC 55, RD-FC 88, R-FC 102, And R-FC 114 for controlling black rot disease on the cabbage cv. Futoški, with possible broader applicability to other cabbage cultivars and Brassicaceae crops.

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