Chemical and Biological Technologies in Agriculture最新文献

Background

Phytoremediation is affected by physical and chemical properties of the soil such as soil pH, moisture, and nutrient content. Soil pH is a key element influencing Cd bioavailability and can be easily adjusted in agricultural practices. The soil pH level may relate to the effectiveness of phytoremediation; however, this has not been extensively investigated. In the current study, we evaluated the effect of Cd contamination level (0.56 and 0.92 mg/kg) and soil pH (5, 6, and 7) on Cd accumulation and allocation in Artemisia argyi, a fast-growing perennial crop.

Results

Our results indicated that higher soil Cd concentrations reduce A. argyi biomass, and the loss of the root mass was particularly significant. Higher soil pH decreased Cd content in stems and roots of A. argyi cultivated in moderately Cd-polluted soil, and increased Cd content in stems and roots of the plant grown in low Cd-polluted soil. Higher soil pH decreased the percentage of Cd distributed in the soluble fraction and cell walls and increased the percentage of Cd in the organelles of leaf cells for moderate soil Cd levels. The bioconcentration and translocation factor exceeded 4.0 and 1.0, respectively, across all tested treatments, indicating that A. argyi is a promising candidate for phytoremediation. Notably, the effects of soil pH on Cd accumulation and subcellular distribution in A. argyi differed between low and moderately Cd-contaminated soils.

Conclusion

Adjustments to soil pH based on the degree of Cd contamination can enhance Cd extraction by A. argyi, thereby reducing the overall remediation cycle of cadmium-polluted paddy fields of South China.

Graphical Abstract

Intercropping is a prevalent soil management strategy within orchards, whereas it is unclear how inoculation with arbuscular mycorrhizal (AM) fungi and intercropping affect tree growth, soil properties, and rhizosphere metabolite profiles. This study investigated the effects of inoculation with Diversispora spurca and intercropping with hairy vetch (Vicia villosa) on biomass production, soil available nutrients, water-stable aggregate (WSA) distribution, phosphatase activity, and secondary metabolite profiles in walnuts (Juglans regia). The intercropping only elevated soil nitrate N levels and WSA distribution at the 0.5–2 mm size, and also triggered 2159 differential metabolites (1378 up-regulated and 781 down-regulated), with armillaramide as the most prominently up-regulated metabolite, followed by the substance diminished upon D. spurca inoculation. Conversely, D. spurca inoculation increased walnut biomass, WSA distribution across the 0.25 − 2 mm size, and acid and neutral phosphatase activities, as well as triggered 2489 differential metabolites (897 up-regulated and 1592 down-regulated), with pteroside D being highest up-regulated differential metabolite, allowing a competitive advantage to AM plants in combating soil pathogens. Despite significantly suppressing root AM fungal colonization and biomass production in AM walnuts, intercropping significantly increased soil ammonium and nitrate N levels in AM walnuts as well as WSAs at the 1–4 mm size, exhibiting a synergistic effect. Flavone and flavonol biosynthesis and pyruvate metabolism were simultaneously involved following AM inoculation or intercropping. Co-application of AM inoculation and intercropping triggered 1006 differential metabolites, with urocanic acid being the most up-regulated metabolite, although it decreased following AM inoculation, suggesting the involvement of mycorrhizal hyphae in soil histidine uptake. Under intercropping, AM inoculation elicited 418 differential metabolites, with the most up-regulated metabolite being implicated in flavonoid pathways. AM inoculation primarily triggered the biosynthesis of unsaturated fatty acids, regardless of intercropping or not, implying a potential increase in unsaturated fatty acid contents of walnut kernels. It concluded that AM inoculation and intercropping interactively affected walnut growth, soil attributes, and soil microenvironment.

Graphical Abstract

Rapid, accurate and non-destructive acquisition of soil total nitrogen (TN) content in the black soil zone is significant for achieving precise fertilization. In this study, the soil types of corn and soybean fields in Jilin Agricultural University, China, were selected as the study area. A total of 162 soil samples were collected using a five-point mixed sampling method. Then, spectral data were obtained and the noisy edge were initially eliminated. Subsequently, the denoised spectral data underwent smoothing by using the Savitzky–Golay (SG) method. After performing the first-order difference (FD) and second-order difference (SD) transformations on the data, it was input to the model. In this study, a hybrid deep learning model, CBiResNet-BiLSTM, was designed for precise prediction of soil TN content. This model was optimized based on ResNet34, and its capabilities were enhanced by incorporating CBAM in the residual module to facilitate additional eigenvalue extraction. Also, Bidirectional Long Short-Term Memory (BiLSTM) was integrated to enhance model accuracy. Besides, partial least squares regression (PLSR), random forest regression (RFR), support vector machine regression (SVR), and back propagation neural network (BP), as well as ResNet(18, 34, 50, 101, 152) models were taken for comparative experiments. The results indicated that the traditional machine learning model PLSR achieved good performance, with R² of 0.883, and the hybrid deep learning model CBiResNet-BiLSTM had the best inversion capability with R² of 0.937, with the R² being improved by 5.4%, compared with the PLSR model. On this basis, we present the LUCAS dataset to demonstrate the generalisability of the model. Therefore, the CBiResNet-BiLSTM model is a fast and feasible hyperspectral estimation method for soil TN content.

Graphical abstract

Glycerol-based biorefinery can be a highly profitable process by producing highly value-added products such as dihydroxyacetone via combined catalytic strategies. Here, two-enzyme system is adopted for the transformation of glycerol into highly valuable dihydroxyacetone as well as cofactor regeneration at the same time. Glycerol dehydrogenase (GDH) and alcohol dehydrogenase (ADH) are co-immobilized within magnetically separable and spherical mesocellular silica foam (Mag-S-MCF), to prepare NER-(GDH/ADH). In details, GDH and ADH are adsorbed into the mesopores of Mag-S-MCF, and further crosslinked within the mesopores of Mag-S-MCF. The resulting nanoscale enzyme reactors (NER) of crosslinked GDH and ADH molecules within the bottle-neck structured mesopores can effectively prevent larger sized crosslinked enzyme aggregates from being leached out of smaller mesopores, due to the bottle-neck mesopore structure of Mag-S-MCF, as well as stabilize the activity of GDH and ADH upon chemical crosslinking, effectively preventing the denaturation of enzyme molecules. More importantly, the proximity of GDH and ADH molecules within mesopores of NER improves the efficiency of cofactor-mediated dual-enzymatic reactions by relieving mass-transfer limitations and improving cofactor recycling in an effective way, expediting both glycerol oxidation and dihydroxyacetone generation at the same time. As a result, the DHA concentration of NER-(GDH/ADH) and the simple mixture of NER-GDH and NER-ADH were 410 μM and 336 μM, respectively. To the best of our knowledge, this report is the first demonstration of stabilized nanoscale multi-enzyme reactor system, equipped with efficient cofactor regeneration within confined mesopores, for efficient glycerol transformation to high-valued dihydroxyacetone.

Graphical Abstract

Microbial and enzyme additives can improve silage performance, but there is limited comparative research on the effects of microbial and enzyme additives on improving silage fermentation quality, and the underlying microbial and metabolic pathways remain unclear. This study investigated the effects without inoculants (CK treatment) or with Lactiplantibacillus plantarum (LP treatment), xylanase (XY treatment) and their combination (LPXY treatment) on the fermentation quality, as well as on the microbial communities and metabolite profiles of the wheat straw silage. The results demonstrated that the LP treatment has a better effect on improving the fermentation quality of wheat straw silage compared to other treatments, as evidenced by markedly (p < 0.05) decreased the pH (4.06), acid and neutral fiber (ANF, NDF, 23.43 and 31.69%DM), and increased the lactic acid (LA, 965.89 mg/L) and acetic acid (AA, 656.10 mg/L) concentrations. After the fermentation process, the LP treatment significantly (p < 0.05) enhanced the abundance of Lactobacillus, reduced bacterial Shannon (p < 0.05) and increased some key metabolites content. The structural equation models (SEMs) and Pearson’s correlation results proved that the LP treatment improved the wheat straw silage fermentation quality via increasing the abundance of Lactobacillus, decreasing the diversity of bacterial community and enriching the content of certain key metabolites. The present study provides mechanistic evidence that Lactiplantibacillus plantarum additive is superior to xylanase additive and their combination on improving fermentation quality of wheat straw silage, that is, by enriching certain key metabolites to increase AA and LA concentrations, providing a reference for the cross study of silage feed fermentation microbiome and metabolome.

Graphical Abstract

Introduction

Boron (B) is critical for plant growth, yet its movement in soil is often hindered by leaching and adsorption, leading to deficiencies. Tackling these issues is essential for boosting agricultural productivity, especially in plants like Eucalyptus with high B needs. This paper aims to address these challenges by evaluating B-doped biochar composites (biochar-B) that enhance B distribution and stability in the soil, focusing on Eucalyptus grandis cultivation in two distinct oxisol types.

Materials and methods

Biochar-B composites were created using shrimp carcass (FSC), chicken manure (FCM) and sewage sludge (FSS), combined with boric acid (BA) and borax (BX), and pyrolyzed at 300 °C and 550 °C. The experimental design was a completely randomized design (CRD) with three replicates.

Results

Fourier transform infrared spectroscopy (FTIR) analysis confirmed successful B integration and interaction with organic matrices, highlighting functional groups responsible for composite properties. This facilitated the development of highly predictive partial least squares (PLS) regression models (R²pred ~ 0.8). The FSC-BA composite at 300 °C showed notable thermal stability, B retention and availability, enhancing B release kinetics.

Discussion

These findings emphasize the importance of considering the soluble B rate in composite applications for Eucalyptus cultivation. The use of these composites provides a sustainable method for gradual B release, potentially outperforming conventional fertilization techniques. This approach may lead to improved plant growth and productivity. Further field investigations are recommended in order to validate these findings and refine sustainable fertilization strategies; thus, benefiting a range of crops.

Graphical abstract

Background

The lignification of branches can promote the accumulation of nutrients, increase plant survival and resistance to biotic and abiotic stresses. As an important carbon source for plants, glucose is also the carbon skeleton for lignin synthesis. Grapevine is a perennial cash crop, and highly lignified branches are essential to ensure the growth of the grapevine plant and the development of the fruit.

Methods

Here, ‘Red Globe’ grape (Vitis vinifera L.) plantlets were selected as the material and cultured with different concentrations of glucose: 0 g/L, 20 g/L, 40 g/L and 60 g/L glucose (G0, G20, G40 and G60). Among them, G0 group as control. Lignin, anthocyanins and glucose contents, plant height and microstructure were measured at each glucose concentration after 40-, 50-, and 60-day treatments. Transcriptome and metabolome were used to analyze the difference in genes and metabolites after 50 days of growth.

Results

After 50 days of cultivation, the lignin content in G40 group was the highest. And the xylem cells number also increased. To further, transcriptome and metabolome have identified a total of 3638 differentially expressed genes (DEGs) (including 245 TFs) and 510 differently accumulated metabolites (DAMs) in three comparison groups. In-depth joint analysis revealed that phenylpropanoid biosynthesis pathway significantly respond to exogenous glucose, and 37 DEGs were identified. Therefore, the phenylpropane biosynthesis pathway may be the key to exogenous glucose to increase lignin levels in grapes, with differential expression of genes being a top priority. These findings provide a new perspective for understanding the relationship between glucose and lignin in grape.

Graphical Abstract

Astragalus membranaceus (AM) roots are a well-known homologous medicine and food in China. AM stems, which are discarded and not used effectively, also contain many active compounds and exhibit beneficial effects. It has the potential to be explored as antibiotic alternative. Fermentation combined with enzymatic hydrolysis (FEH) is an effective strategy for extracting polyphenol and improving the usage of AM stems. Therefore, in this study, the conditions of FEH and extraction for polyphenol in AM stems were screened. The antioxidant activity of extract from AM stems without and with FEH (AMSE and FAMSE) was evaluated. The metabolite profiles of phenolic acids and flavonoids in AMSE and FAMSE were characterized by ultra-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC–ESI-MS/MS). The results showed that the highest polyphenol content from AM stems was obtained with cellulase and pectinase (1:1, 2000 U/g), moisture content 43%, fermentation temperature 30 °C, and fermentation time 7 days. Selected extraction conditions of polyphenol were ethanol concentration 50%, ultrasonic power 500 W, extraction temperature 35 °C, and extraction time 40 min. On this condition, compared with AMSE, the polyphenol and flavonoid contents in FAMSE were significantly higher. FAMSE exhibited stronger DPPH, hydroxyl radical scavenging rate and reducing power than AMSE. The relative content of 3-(4-hydroxyphenyl)-propionic acid, dihydroferulic acid, isoferulic acid, 4-hydroxybenzoic acid, 4-hydroxyphenyllactic acid, ferulic acid, vanillic acid, syringic acid, gentisic acid, sinapic acid, apigenin, tricin, acacetin, daidzein, genistein, formononetin, prunetin, pratensein, rhamnocitrin and galangin were significantly upregulated in FAMSE.

Graphical Abstract

Background

The root-associated microbiomes are crucial in promoting plant growth and development through symbiotic interactions with their hosts. Plants may shape their microbiomes by secreting specific root exudates. However, the potential mechanisms how plant species determine root exudates and drive microbiome assembly have been little studied. In this study, three wild tobaccos and one cultivated tobacco were used to investigate the commonalities and differences of both root-associated microbiomes and root exudates.

Results

Amplicon sequencing results suggested that tobacco species significantly affected microbial communities in both the rhizosphere and root endosphere, with the strongest impact on the fungal community in the root endosphere. The microbial networks of wild tobacco species were more stable than that of the cultivated tobacco, and fungal members played a more important role in the networks of wild tobacco species, while bacterial members did so in the cultivated tobacco. The rhizosphere bacteria of wild tobacco species showed a higher functional diversity than that of the cultivated tobacco, while the bacteria in the root endosphere presented a contrary pattern. Metabolomics analysis showed significant differences in the composition and abundance of root exudates among the four tobacco species, and the greatest difference was found between the three wild species and the cultivated one. Correlation analysis showed the strongest correlation between metabolites and rhizosphere bacteria, in which O-benzoic acid (2-methoxybenzoic acid) had the most positive correlations with rhizosphere bacteria, while β-ureidoisobutenoic acid had the most negative correlations with rhizosphere bacteria. The rhizosphere bacteria Streptomyces, Hydrophilus and Roseobacter had the strongest positive correlations with metabolites, and the rhizosphere bacterium Nitrobacter had the most negative correlations with metabolites.

Conclusion

This study revealed the differences of microbial communities and root exudates in the rhizosphere and root endosphere of four tobacco species, which can further improve our understanding of plant–microbiome interactions during crop domestication.

Graphical Abstract

Selenium (Se) is one of the essential trace elements for humans. Plants are the main source of Se for humans, while soil Se is the primary source of Se for plants. Biofortification, which involves the transfer of Se from soil to plants and animals, is currently recognized as the safest and most effective approach for Se supplementation for humans. However, Se in soil primarily exists in forms that plants cannot easily utilize, so enhancing Se transfer from soil to plants is crucial for optimal Se utilization. In this paper, we provided a comprehensive analysis of Se forms in soil. Then we summarized the strategies for enhancing Se transfer from soil to plants. These strategies include adjusting redox potential, managing soil moisture, modulating pH value, improving organic matter, optimizing ion competition, promoting beneficial microbes, and considering the synergy between plant rhizosphere and soil. Furthermore, we reviewed Se forms and metabolism after uptake into plants to better understand its role in human health. Finally, we came up with the challenges and perspectives, to provide new insights for further study in this area. This work also offers potential solutions for enhancing Se transformation from soil to plants and utilizing soil Se to produce naturally Se-rich products.

Graphical Abstract