Chemical and Biological Technologies in Agriculture最新文献

Background

Studies have shown that plant endophytic microbial communities are ubiquitous and closely related to plant growth and health. To clarify the mechanism of the melon varieties with high resistant to wilt, the endophytic microbial compositions and metabolites in roots of melon varieties with high resistant ability to wilt were analyzed.

Results

The results showed that the abundances of Firmicutes, Ascomycota, Bacillus, Bradyrhizobium, Amycolatopsis, Actinospica, and Catenulispora all increased in roots of wilt high resistant melon varieties (MT) which compared to wilt susceptible melon varieties (MS). Meanwhile, Ochrobactrum, Bordetella, Roseateles, Staphylococcus, Acidovorax, Amycolatopsis, Catenulispora, Promicromonospora, and Gymnopilus were the unique endophytic microbes in roots of MT. Moreover, in comparison with the MS varieties, the functions of Defense mechanisms, Secondary metabolites biosynthesis, transport and catabolism, Nucleotide transport and metabolism, Signal transduction mechanisms, Coenzyme transport and metabolism, Carbohydrate transport and metabolism and Amino acid transport and metabolism all increased in roots of MT varieties. Additionally, the nucleotide metabolism and biosynthesis of cofactors metabolic pathways were also significantly increased in roots of MT varieties. On the other hand, the untargeted metabolome results showed that Biosynthesis of various plant secondary metabolites, Nucleotide metabolism and Biosynthesis of cofactors metabolic pathways were significantly increased in the expression of MT varieties; and the content of metabolic compounds such as flavonoids, Cinnamic acid compounds, Organic acid compounds, and Nucleotides were increased. In addition, the correlation between microbiome and metabolome indicates a significant correlation between the two.

Conclusions

All above results suggested that higher abundant antagonistic microbes and metabolic functions of endophytes in roots of wilt high resistant melon varieties (MT) were the important mechanisms for their high resistance to wilt.

Graphical Abstract

Background

Magnolia kobus belongs to the Magnoliaceae family and the genus Magnolia. The flowers are widely used in herbal tea and dietary supplements. It is effectively used in traditional medicines and its chemical constituents have various biological activities, such as anti-obesity, antioxidant, anticancer, anti-inflammatory, and anti-hyperlipidaemic activities. The flower developmental process of M. kobus involves a complex regulatory network and is intensively related to the quality and relative composition of primary and secondary metabolites of the flower. Hence, the identification of metabolic changes during different developmental stages of the flower was important for enhancing organoleptic and nutritional characteristics. To our knowledge, to date, none of the studies has investigated the relationship between metabolic changes (primary and secondary metabolites) during different developmental stages of the M. kobus flower.

Results

This study investigated metabolic changes in 47 hydrophilic and 13 lipophilic compounds and biological activities in Magnolia kobus flowers during four developmental stages. Metabolites were identified using HPLC, GC–qMS, and GC–TOFMS. Throughout flower development, metabolite accumulation showed significant differences based on metabolomics approaches. The dynamic changes of 21 differential metabolites occurred between the young and mature stages. Flower buds exhibited high levels of phenylpropanoids and phytosterols. The total phenolic and flavonoid contents were most abundant in the buds and decreased from the bud to the old stages. Flower bud extracts showed the most powerful effects in three antioxidant assays and antibacterial effects against 10 pathogenic bacterial strains.

Conclusions

These findings emphasise the value of M. kobus flower buds as an edible natural source and provide valuable insight into the metabolic changes that occur in M. kobus flowers during development.

Graphical Abstract

Background

Xenobiotics like pesticide isoproturon (IPU) and heavy metal cadmium (Cd) are environmental contaminants posing serious impacts on ecosystem. Understanding their toxic and accumulative processes is crucial to uncover insightful mechanisms and minimize health risks. However, the joint effect of IPU and Cd on microorganisms in aquatic ecosystems remains elusive. In this study, Chlamydomonas reinhardtii was selected as a model unicellular organism to evaluate the ecotoxicological effects of IPU and Cd, focusing on biological responses, bioaccumulation capacity, and environmental adaptation.

Results

The combined treatment with IPU (0.24 μmol L⁻¹) and/or Cd (20 μmol L⁻¹) for 60 h can induce acute toxicity to C. reinhardtii, reducing chlorophyll and photosynthetic fluorescence, while increasing oxidative damage manifested by lipid membrane peroxides and electrical conductivity. IPU and Cd were accumulated in C. reinhardtii. Interestingly, IPU accumulation in algae was significantly repressed in the presence of Cd, showing a remarkable decrease of 116.7% compared to the IPU treatment alone. Similarly, the Cd concentration in the cells exposed to IPU was reduced by 23.5% compared to Cd treatment alone. Calculation of the bioconcentration factors revealed lower accumulation values of IPU or Cd in algae under Cd+IPU exposure compared to IPU or Cd stress, suggesting an antagonistic interaction between IPU and Cd during absorption by the algae. Furthermore, the activities and transcriptional expression of enzymatic antioxidants such as SOD and APX were significantly induced by Cd stress, whereas the activities of CAT, APX, and PPO significantly increased elevated by IPU.

Conclusions

This study provides compelling evidence of the ecotoxicological effects of combined IPU and cadmium contamination on algae, highlighting the potential of algae for bioremediation of environments contaminated with IPU and cadmium.

Graphical Abstract

The interaction of the polyphenol–protein–polysaccharide ternary system plays a critical regulatory role in many biological processes including cellular signal transduction, molecular recognition, and assembly. Moreover, the interactions of the three elements can form complex molecular structures and affect their respective functions and activities. It is necessary to clarify the correlation between the binding force and functional characteristics of polyphenols, proteins, and polysaccharides in the ternary system to effectively improve the sensory, functional, and nutritional properties of food. Hence, this paper systematically reviews the interactions of the ternary system composed of polyphenols, proteins, and polysaccharides. Moreover, this article also analyzes the interaction between the two components in the ternary system based on the functional characteristics of these components. Furthermore, this review comprehensively introduces the application of ternary systems. The findings are expected to provide important guidance for the polyphenol–protein–polysaccharide ternary system in biology, medicine, and food industry.

Graphical Abstract

Background

Crop rotation changes crop species and the associated management strategies, significantly influencing soil fertility and soil microbial communities. Interactions among the species in microbial communities are important for soil nutrient cycling. Yet, the contribution of soil microbial interactions to crop yield and soil nitrogen-cycle function under wheat–maize and wheat–soybean rotation conversion remains unclear. An 8-year field experiment was conducted to investigate the impact of simple [8-year wheat–maize rotation (8WM) and 8-year wheat–soybean rotation (8WS)] and diverse cropping systems [4-year wheat–soybean followed by 4-year wheat–maize rotation (4WS4WM) and 4-year wheat–maize followed by 4-year wheat–soybean rotation (4WM4WS)] on crop yield, soil properties, bacterial–fungal co-occurrence networks and nitrogen functional potentials. The abundances of genes with nitrogen fixation (nifH), nitrification (AOB and nxrA) and denitrification (narG, nirK, norB and nosZ) potentials were quantified and bacterial and fungal communities were characterized.

Results

4WS4WM led to higher succeeding maize yields and lower bacterial–fungal network complexity, nitrogen fixation potentials and denitrifying potentials than 8WM. Meanwhile, 4WM4WS exhibited higher succeeding wheat and soybean yields, network complexity and lower nitrifying potentials than 8WS. The ecological cluster with the most nitrifying and denitrifying bacterial species (Module#5) and that with the least species (Module#3) dominated the potentials of nitrogen fixation, nitrification and denitrification and succeeding maize yields in 4WS4WM and 8WM. Module#4 with the highest abundances of nitrifying bacteria (Nitrosomonadaceae) and Module#2 with the most species dominated the nitrifying potentials and succeeding wheat and soybean yields in 4WM4WS and 8WS. Soil water content, organic carbon, dissolved organic carbon, NO₃⁻ and pH were key drivers influencing Module#3 and Module#5, while only NH₄⁺ significantly affected Module#2 and Module#4.

Conclusions

These findings demonstrate the importance of ecological clusters within soil microbial network in regulating crop yield and soil nitrogen cycling, and identify specific ecological clusters dominating nitrogen functional potentials in wheat–maize and wheat–soybean rotations, offering science-based recommendations for sustainable crop rotation practices.

Graphical Abstract

Background

Sheep manure and mushroom residue are common agricultural waste which threaten environment but rich in mineral elements and organic matter. Even though fermentation and adding it to soil for crop growth is a commonly used approach, there are concerns about how efficient the fermentation process is and whether the microbial community remains safe for both the crops and those working in agriculture. We have discovered a composite microbial agent, previously known as CMA, that demonstrates significant efficacy in the fermentation of mushroom residue and sheep manure. Despite its high activity, the impact of this microbial agent on soil nutrient release, soil microbial composition, and plant growth remains still uncertain.

Results

After fermenting sheep manure and mushroom residue with Bacillus CMA, this study investigated the fermentation products mixed with vermiculite and perlite for the cultivation of tomato. The results demonstrate that the composite substrate align closely within the ideal range for seedling substrates. Notably, compounded with CMA compost products and vermiculite in a 2:1 ratio, yields the most favorable growth for tomato, which may be attributed to the increased nutrient release and most favorable microbial conditions. Moreover, it significantly decreased the abundance of pathogenic bacteria harmful to human and animal health, thereby reducing the risk to individuals engaged in field labor, and mitigating the threat of plant pathogenic bacteria.

Conclusions

Sheep manure and mushroom residue fermentation with CMA added significantly promoted tomatoes growth and reduced the risk of diseases in crops, animals, and people. These findings hold significant implications also for the reuse of agricultural biowaste and residues, besides the crop growth and safety of humans and animals in agricultural environments.

Graphical Abstract

Background

Centella Asiatica has been shown to have beneficial value for the treatment of tumors. However, its active ingredients and molecular mechanisms of action have not been fully elucidated. Pectic polysaccharides are the primary active components from medicinal plants. Moreover, these polysaccharides are regarded as potential inhibitors of galectins, such as galectin-1, -3, -7, that generally promote tumor growth. Nevertheless, detailed structural analysis of pectic polysaccharides from Centella Asiatica is sorely lacking, as is knowledge of their interactions with galectins.

Methods

Water-soluble pectic polysaccharides (WCAP) isolated from Centella Asiatica were purified into two homogeneous fractions (WCAP-A2b and WCAP-A5b) by a combination of anion-exchange and gel-permeation chromatography. Monosaccharide composition, FT-IR, NMR and enzymatic analyses were used to characterize their structural features. Furthermore, the interactions between galectin-1, -3, -7 and a series of these polysaccharides, including two pectin fractions and their structural domains produced by enzymatic hydrolysis, were evaluated by using hemagglutination and biolayer interferometry.

Results

WCAP-A2b and WCAP-A5b have weight averaged molecular weights of 30.0 kDa and 34.0 kDa, respectively, and both polysaccharides consist of rhamnogalacturonan I (RG-I), rhamnogalacturonan II (RG-II) and homogalacturonan (HG) domains, with mass ratios of 1.3: 1.0: 1.4 and 1.1: 1.0: 2.4, respectively. Their RG-I domains contain arabinan, galactan, and/or arabinogalactan, along with neutral sugar side chains that are more prevalent in WCAP-A2b than in WCAP-A5b. Hemagglutination and biolayer interferometry binding assays indicate that galectin-3 vis-à-vis galectin-1 and -7, binds strongly to the RG-I domain (likely via its neutral side chains) in WCAP-A5b, thereby inhibiting galectin-3-mediated cell–cell interactions.

Conclusions

Our study provides structural information on pectin polysaccharides from Centella Asiatica. Results suggest that RG-I domains from WCAP-A5b and WCAP-A2b may be developed as potential inhibitors of galectin-3-mediated cell–cell adhesion and tumor growth.

Graphical Abstract

Background

Humic acid affects plant growth. Its source and structure may play a central role to its functionality. The relationship between humic acid and plant bioactivity is still unclear. This study investigated the biostimulation effects of two natural humic acids derived from soil (SHA) and lignite (LHA) on Lepidium sativum in comparison to a synthetic humic acid model (HALP) with known structure.

Results

All humic acids positively affected cress seed germination and root elongation. Greater root hairs density and dry matter, compared to control, were observed using concentration of 5 mg L⁻¹ for HALP, 50 mg L⁻¹ for LHA, and 100 mg L⁻¹ for SHA. The germination index was the largest (698% more effective than control) with 50 mg L⁻¹ of SHA, while it was 528% for LHA, and 493% for HALP at 5 mg L⁻¹. SHA contained the lowest aromatic and phenolic C content, the largest pK₂ value of 9.0 (7.7 for LHA and 7.6 for HALP), the least ratio between the aromaticity index and lignin ratio (ARM/LigR) of 0.15 (0.66 for LHA and 129.92 for HALP), and at pH 6.3 the lowest amount of free radicals with a value of 0.567 × 10¹⁷ spin g⁻¹ (1.670 × 10¹⁷ and 1.780 × 10¹⁷ spin g⁻¹ for LHA and HALP, respectively), with the greatest g value of 2.0039 (2.0035 for LHA and 2.0037 for HALP).

Conclusions

The overall chemical structure of humic acids exerted a biostimulation of cress plantlets. The level of the intrinsic stable free radicals identified by EPR in the humic acids resulted well correlated to the ARM/LigR ratio calculated by NMR. Our results suggested that HA biostimulation effect is related to its applied concentration, which is limited by its free radical content. The modulation of the humic supramolecular structure by ROS and organic acids in root exudates can determine the release of bioactive humic molecules. When the content of the intrinsic humic free radicals is high, possible molecular coupling of the bioactive humic molecules may hinder their biostimulation activity. In such cases, a low humic acid concentration appears to be required to achieve the optimum biostimulation effects.

Graphical Abstract

Background

Guangxi is the leading sugarcane-producing area in China. Due to the Panama disease outbreak in banana gardens, sugarcane and banana rotation was recommended. A field experiment with the newly released sugarcane cultivar Zhongzhe 1 (ZZ1) was conducted to understand the role of the sugarcane–banana rotation system in shaping the rhizosphere microbiota. Fields in the region possess characteristics of red laterite soil.

Results

Using Illumina HiSeq sequencing to analyze soil samples’ 16S rRNA V3-V4 region, the preceding banana rotation field had relatively greater bacterial diversity than the monoculture sugarcane field. Proteobacteria, Chloroflexi, Actinobacteria, and Acidobacteria were the dominant phyla, with distinct taxa enriched in each environment. However, the preceding sugarcane monoculture field enriched functional groups related to nitrogen fixation and cellulolysis. Network analysis highlighted contrasting network structures between sugarcane and banana rhizospheres, suggesting differential stability and susceptibility to environmental influences. Furthermore, correlations between soil properties and bacterial alpha-diversity underscored the influence of preceding crops on rhizosphere microbial communities.

Conclusion

This research enhances our understanding of crop rotation effects on soil microbial ecology and provides insights into optimizing agricultural practices for enhanced soil health and crop productivity. Future studies should explore the underlying mechanisms driving these interactions and evaluate the long-term impacts of crop rotation on soil microbial dynamics.

Graphical abstract

Background

Discarded potato is the most abundant potato waste and represents a worldwide disposal problem to the potato industry. This agricultural waste contains valuable nutrients that could be used as substrate to obtain diverse high value-added microbial products, such as biopigments. The aim of this work was to evaluate the use of discarded potato as a sole substrate source for producing blue pigments by Streptomyces lydicus PM7 through submerged fermentation.

Results

Initially, the traditional culture medium ISP2 was established as suitable for inoculum preparation, as it allowed high growth rates and consumption of ~ 75% reducing sugar, leading to 1.3 g L⁻¹ dry biomass at 72 h of incubation. The formulated discarded potato broth (DPB) medium was evaluated together with five other traditional liquid culture media (potato dextrose broth, ISP2, ISP3, ISP4, and ISP5) for producing blue pigments by S. lydicus PM7. The highest blue pigment production was obtained by using DPB medium, reaching ~ 0.97 g L⁻¹, followed by ISP5 (~ 0.36 g L⁻¹). In terms of evaluating the concentration of discarded potato powder, the highest concentration of blue pigments was obtained with 16 g L⁻¹, compared to concentrations of 4, 8, and 32 g L⁻¹. In general, a notable increase in total proteins (~ 14 g L⁻¹ in biomass; ~ 8 g L⁻¹ in medium) and reducing sugars (~ 5 g L⁻¹) on the fifth day of DPB fermentation was observed, at which time the production of blue pigments began. These data proved that S. lydicus PM7 is able to degrade potato wastes during submerged fermentation and to direct metabolism towards the formation of biopigments. Chromatographic analysis revealed that the main blue pigment produced by new strain in this complex medium is actinorhodin.

Conclusions

Discarded potato favored the production of blue pigments by S. lydicus PM7 under submerged fermentation, leading to final product concentration almost three times higher than others traditional Streptomyces culture media. To the best of our knowledge, this is the first report on the production of actinorhodin by the specie S. lydicus, as well as on this pigment synthesis based on an agricultural waste as a sole nutrient source for fermentation process. The findings showed that potato waste could be a potential byproduct for replacement of commercial culture media using for this same purpose.

Graphical Abstract