Chemical and Biological Technologies in Agriculture最新文献

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.

Graphical Abstract

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.

Graphical Abstract

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.

Graphical Abstract

Background

Pecan [Carya illinoinensis (Wangenh.) Koch] is a widely cultivated dried fruit and woody oil tree with high economic value. Continuous sole planting of pecan caused some land to lie idle and deterioration of soil conditions. Tree and medicinal crops intercropping represents an environmental-friendly and economically feasible solution to these issues. Thus, we aimed to explore the underlying mechanism by which intercropping improved soil condition by regulating the interactions of the soil microbiome and metabolome. In this study, pecans were intercropped with medicinal crops caper spurge and honeysuckle on a tree farm in China. A combined analysis of soil microbiomes and metabolomes was performed to discover the effects of intercropping on bulk and rhizosphere soils.

Results

The results showed that intercropping improved the edaphic properties of bulk soil and promoted the growth of pecan and caper spurge. Intercropping also significantly altered the structures of both bacterial and fungal communities in bulk soil, stabilised the enrichment of nitrogen-cyclic bacteria, for instance, Bacillus, and decreased the relative abundances of plant–pathogenic fungi, for instance, Fusarium. In addition, the result of metabolomic analysis showed that intercropping promoted the synthesis of functional compounds, such as trehalose and ethanolamine, which enhanced plant disease resistance in bulk soils. Moreover, the co-occurrence networks of microbiomes and metabolomes of bulk soils revealed that Bacillus was significantly correlated with Fusarium, Alternaria, and trehalose under intercropping patterns. Furthermore, analysis of microbiomes and metabolomes in the rhizosphere soil of caper spurge and honeysuckle revealed that Penicillium and Rhizomicrobium were significantly increased by intercropping and showed more dynamic connections with other genera and metabolites compared with single planting.

Conclusions

Overall, intercropping pecans with caper spurge and honeysuckle can improve soil conditions and promote plant growth through microbiological and metabolomics integrated analyses. This study provides valuable information and theoretical basis for optimizing land resource utilisation and improving soil conditions in tree fields like pecan fields via intercropping, thereby reducing production losses and ensuring economic benefits.

Graphical Abstract

Plants and microorganisms have been co-evolving and interacting for billions of years. Prior researchers have explored the plant’s immune system responses and interaction with diverse microbes, but several ambiguities need further explanation. This review provides insight into mechanisms underlying plant–microbe interaction and knowledge dearth domains, along with possibilities to use beneficial microbes to improve plant growth, disease resistance, nutritional value, and productivity. Microorganisms in the phyllosphere and the rhizosphere could be beneficial or pathogenic. Host plants use their innate immune system and the antagonistic competence of plant-growth-promoting microbes against pathogens. The innate immune system of plants has two paramount protection forms involving different types of immune receptors, which assist in recognizing non-self-components. The first group of receptors is membrane-resident pattern recognition receptors (PRRs), which are responsible for sensing microbe-associated molecular patterns (MAMPs) and damage-associated molecular patterns (DAMPs). The second group consists of intracellular immune sensors, specifically resistance (R) proteins, astute in recognizing the structure or function of strain-specific pathogen effectors injected into host plant cells. Plants activate their pattern-triggered immunity (PTI) and effector-triggered immunity (ETI) defense mechanisms to counter the infection. Plants benefit from certain microbes by promoting their growth, disease resistance, and resilience under various stress conditions in exchange for shelter and nutrients.

Graphical Abstract

Background

The paper mulberry (Broussonetia papyrifera L.) is a valuable source of woody forage that can be used for ruminants, such as goat and lambs. However, there is limited knowledge about how paper mulberry silage affects carcass characteristics, meat physicochemical attributes, amino acid and unsaturated fatty acids in Hu lambs compared to alfalfa silage. The objective of this experiment was to investigate the impact of substituting alfalfa silage with paper mulberry silage on the slaughter performance, meat quality, free amino acid and fatty acid composition in muscles of Hu lambs.

Results

Thirty 60-day-old male Hu lambs with 17.13 ± 0.26 kg body weight were randomly allocated into paper mulberry silage (30% of total mixed ration) and alfalfa silage (30% of total mixed ration) treatment, and the feeding trial lasted 70 days. The results indicated no significant differences in all measurements (P > 0.05). However, compared to the group fed with alfalfa silage, the group fed with paper mulberry silage exhibited a reduction in meat drip loss (P < 0.05) without any notable effect on meat nutrients (P > 0.05). Targeted metabolomics analysis revealed that feeding paper mulberry silage led to decreased levels of certain bitter amino acids, such as valine, leucine, isoleucine, tryptophan, and phenylalanine (P < 0.05). Furthermore, the consumption of paper mulberry silage significantly augmented the levels of monounsaturated and polyunsaturated fatty acids, particularly n6-polyunsaturated fatty acids (C18:2n6, C20:3n6, C20:4n6, etc.), in meat.

Conclusions

Substituting paper mulberry silage for alfalfa in the daily diet of Hu lambs not only has no detrimental effect on animal performance but also improves meat unsaturated fatty acid composition.

Graphical Abstract

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