Search Results (2,128)

Wheat production is intrinsically linked to global food security. However, wheat cultivation is constrained by the progressive degradation of soil conditions resulting from the continuous application of fertilizers. This study aimed to examine the effects of deep tillage on rhizosphere soil microbial communities and their potential role in improving soil quality, given that the specific mechanisms driving these observed benefits remain unclear. Soil fertility in this research was evaluated through the analysis of various soil parameters, including total nitrogen, total phosphorus, total potassium, available phosphorus, and available potassium, among others. The high-throughput sequencing technique was utilized to examine the rhizosphere microbial community associated with deep tillage wheat. The findings indicated that deep tillage cultivation of wheat led to reduced fertility levels in the 0–20 cm soil layer in comparison with non-deep tillage cultivation. A sequencing analysis indicated that Acidobacteria and Proteobacteria are the dominant bacterial phyla, with Proteobacteria being significantly more abundant in the deep tillage group. The dominant fungal phyla identified were Ascomycota, Mortierellomycota, and Basidiomycota. Among bacterial genera, Arthrobacter, Bacillus, and Nocardioides were predominant, with Arthrobacter showing a significantly higher presence in the deep tillage group. The predominant fungal genera included Mortierella, Alternaria, Schizothecium, and Cladosporium. Deep tillage cultivation has the potential to enhance soil quality and boost crop productivity through the modulation of soil microbial community structure. Full article

Populus euphratica, Tamarix ramosissima, and Sophora alopecuroides are, respectively, typical arboreal, shrubby, and herbaceous species in oases of arid regions. It is important to study the difference in metabolic characteristics of the rhizosphere fungal community of these plant species and their relationships with soil factors for the preservation of delicate arid oasis ecosystems with future environmental changes. In this study, we, respectively, collected 18 rhizosphere soil samples of P. euphratica, T. ramosissima, and S. alopecuroides to explore the difference in rhizosphere fungal metabolic characteristics of different plant life forms and their underlying driving factors. The results showed that (1) soil physicochemical properties (including soil water content, pH, etc.) were significantly different among different plant species (p < 0.05). (2) Rhizosphere fungal metabolic characteristics were significantly different between S. alopecuroides and T. ramosissima (ANOSIM, p < 0.05), which was mainly caused by the different utilization of carboxylic carbon. (3) The RDA showed that the main driving factors of the variations in rhizosphere fungal metabolic characteristics were different among different plant species. The main explanatory variables of the variations in the metabolic characteristics of the rhizosphere fungal community were carbon to nitrogen ratio (23%) and available potassium (17.4%) for P. euphratica, while soil organic carbon (23.1%), pH (8.6%), and total nitrogen (8.2%) for T. ramosissima, and soil clay content (36.6%) and soil organic carbon (12.6%) for S. alopecuroides. In conclusion, the variations in rhizosphere fungal metabolic characteristics in arid oases are dominantly affected by soil factors rather than plant life forms. Full article

Cucumber is one of the top ten vegetables globally and is widely cultivated worldwide. However, Fusarium wilt, caused by Fusarium oxysporum f. sp. Cucumerinum, is one of the most serious soil-borne diseases in cucumber cultivation, causing significant economic losses. Biological control has great potential in the prevention of cucumber wilt disease, but the mechanism involved still needs further research. In this study, biocontrol isolate Bacillus subtilis 1JN2, which was isolated in our previous work, was evaluated in field conditions against Fusarium wilt, and the rhizosphere fungal diversity was analyzed. The results indicated that the biocontrol efficacy of B. subtilis 1JN2 reached 58.5% compared with the blank control, and the population density of F. oxysporum in the rhizosphere decreased from 495 copies/g of soil before inoculation to 20 copies/g 14 days after treatment. High-throughput sequencing demonstrated that after an inoculation of 1JN2, the populations that decreased significantly include the genera of Olpidium and Pseudallescheria, from more than 20% to less than 8%. And the most increased population belonged to the family Chaetomiaceae, from 6.82% to 18.77%, 12.39%, 44.41%, and 19.41% at the four sample time points after treatment. In addition, soil-related enzyme activities, including catalase, soil dehydrogenase, alkaline phosphatase, and polyphenol oxidase, were analyzed before and after treatment with 1JN2. The results indicated that all the enzyme activities showed an upward trend following inoculation. These findings demonstrate the potential of using B. subtilis 1JN2 as a biocontrol agent for controlling Fusarium wilt in cucumber. Full article

The rhizosphere of plants contains a wide range of microorganisms that can be cultivated and used for the benefit of agricultural practices. From garden soil near the rhizosphere region, Strain ES10-3-2-2 was isolated, and the cells were Gram-negative, aerobic, non-spore-forming rods that were 0.3–0.8 µm in diameter and 1.5–2.5 µm in length. The neighbor-joining method on 16S rDNA similarity revealed that the strain exhibited the highest sequence similarities with “Fibrivirga algicola JA-25” (99.2%) and Fibrella forsythia HMF5405^T (97.3%). To further explore its biotechnological potentialities, we sequenced the complete genome of this strain employing the PacBio RSII sequencing platform. The genome of Strain ES10-3-2-2 comprises a 6,408,035 bp circular chromosome with a 52.8% GC content, including 5038 protein-coding genes and 52 RNA genes. The sequencing also identified three plasmids measuring 212,574 bp, 175,683 bp, and 81,564 bp. Intriguingly, annotations derived from the NCBI-PGAP, eggnog, and KEGG databases indicated the presence of genes affiliated with radiation-resistance pathway genes and plant-growth promotor key/biofertilization-related genes regarding Fe acquisition, K and P assimilation, CO₂ fixation, and Fe solubilization, with essential roles in agroecosystems, as well as genes related to siderophore regulation. Additionally, T1SS, T6SS, and T9SS secretion systems are present in this species, like plant-associated bacteria. The inoculation of Strain ES10-3-2-2 to Arabidopsis significantly increases the fresh shoot and root biomass, thereby maintaining the plant quality compared to uninoculated controls. This work represents a link between radiation tolerance and the plant-growth mechanism of Strain ES10-3-2-2 based on in vitro experiments and bioinformatic approaches. Overall, the radiation-tolerant bacteria might enable the development of microbiological preparations that are extremely effective at increasing plant biomass and soil fertility, both of which are crucial for sustainable agriculture. Full article

To explore and utilize the abundant soil microorganisms and their beneficial functions, high-throughput sequencing technology was used to analyze soil microbial compositions in the rhizosphere of red and green amaranth varieties. The results showed that significant differences in soil microbial composition could be found in the rhizosphere of amaranth plants with different color phenotypes. Firstly, soil bacterial compositions in the rhizosphere were significantly different between red and green amaranths. Among them, Streptomyces, Pseudonocardia, Pseudolabrys, Acidibacter, norank_ f_ Micropepsaceae, Bradyrhizobium, and Nocardioides were the unique dominant soil bacterial genera in the rhizosphere of red amaranth. In contrast, Conexibacter, norank_f_norank_o_norank_c_TK10, and norank_f_ norank_o_ norank_ c_AD3 were the special dominant soil bacterial genera in the rhizosphere of green amaranth. Additionally, even though the soil fungal compositions in the rhizosphere were not significantly different between red and green amaranths, the abundance of the dominant soil fungal genera in the rhizosphere showed significant differences between red and green amaranths. For example, unclassified_k__Fungi, Fusarium, Cladophialophora, unclassified_c__Sordariomycetes and unclassified_p__Chytridiomycota significantly enriched as the dominant soil fungal genera in the rhizosphere of the red amaranth. In contrast, Aspergillues only significantly enriched as the dominant soil fungal genus in the rhizosphere of green amaranth. All of the above results indicated that amaranth with various color phenotypes exactly recruited different microorganisms in rhizosphere, and the enrichments of soil microorganisms in the rhizosphere could be speculated in contributing to amaranth color formations. Full article

Soil-borne diseases are exacerbated by continuous cropping and negatively impact maize health and yields. We conducted a long-term (11-year) field experiment in the black soil region of Northeast China to analyze the effects of different cropping systems on maize yield and rhizosphere soil fungal community structure and function. The experiment included three cropping systems: continuous maize cropping (CMC), maize–soybean rotation (MSR), and maize–soybean intercropping (MSI). MSI and MSR resulted in a 3.30–16.26% lower ear height coefficient and a 7.43–12.37% higher maize yield compared to CMC. The richness and diversity of rhizosphere soil fungi were 7.75–20.26% lower in MSI and MSR than in CMC. The relative abundances of Tausonia and Mortierella were associated with increased maize yield, whereas the relative abundance of Solicoccozyma was associated with decreased maize yield. MSI and MSR had higher proportions of wood saprotrophs and lower proportions of plant pathogens than CMC. Furthermore, our findings indicate that crop rotation is more effective than intercropping for enhancing maize yield and mitigating soil-borne diseases in the black soil zone of Northeast China. This study offers valuable insights for the development of sustainable agroecosystems. Full article

Intercropping medicinal plants plays an important role in agroforestry that can improve the physical, chemical, and biological fertility of soil. However, the influence of intercropping medicinal plants on the Camellia oleifera soil properties and bacterial communities remains elusive. In this study, five intercropping treatment groups were set as follows: Curcuma zedoaria/C. oleifera (EZ), Curcuma longa/C. oleifera (JH), Clinacanthus nutans/C. oleifera (YDC), Fructus Galangae/C. oleifera (HDK), and Ficus simplicissima/C. oleifera (WZMT). The soil chemical properties, enzyme activities, and bacterial communities were measured and analyzed to evaluate the effects of different intercropping systems. The results indicated that, compared to the C. oleifera monoculture group, YDC and EZ showed noticeable impacts on the soil chemical properties with a significant increase in total nitrogen (TN), nitrate nitrogen (NN), available nitrogen (AN), available phosphorus (AP), and available potassium (AK). Among them, the content of TN and AK in the rhizosphere soil of Camellia oleifera in the YDC intercropping system was the highest, which was 7.82 g/kg and 21.94 mg/kg higher than CK. Similarly, in the EZ intercropping system, the content of NN and OM in the rhizosphere soil of Camellia oleifera was the highest, which was higher than that of CK at 722.33 mg/kg and 2.36 g/kg, respectively. Curcuma longa/C. oleifera (JH) and Clinacanthus nutans/C. oleifera (YDC) had the most effect on soil enzyme activities. Furthermore, YDC extensively increased the activities of hydrogen peroxide and acid phosphatase enzymes; the increase was 2.27 mg/g and 3.21 mg/g, respectively. While JH obviously increased the urease activity, the diversity of bacterial populations in the rhizosphere soil of the intercropping plants decreased, especially the Shannon index of YDC and HDK. Compared with the monoculture group, the bacterial community abundance and structure of JH and YDC were quite different. The relative abundance of Actinobacteriota and Firmicutes was increased in YDC, and that of Acidobacteriota and Myxococcota was increased in JH. According to the redundancy analysis (RDA), pH, total potassium, and soil catalase activity were identified as the main factors influencing the microbial community structure of the intercropping systems. In conclusion, intercropping with JH and YDC increased the relative abundance of the dominant bacterial communities, improved the microbial community structure, and enhanced the soil nutrients and enzyme activities. Therefore, in the future, these two medicinal plants can be used for intercropping with C. oleifera. Full article

The bacterial communities in the rhizosphere soil of plants facilitate the cycling of nutrient elements in the rhizosphere and regulate soil fertility. By analyzing the microecological structure of rhizosphere soil surrounding wild celery, we can provide a basis for the bionic cultivation of wild celery. In this experiment, rhizosphere soil samples from various wild celery varieties in Jilin Province were used as test materials, and high-throughput sequencing was employed to analyze and compare the rhizosphere bacterial community structures of these samples. After screening and removing chimeric sequences, a total of 1,020,108 high-quality sequences were obtained. Species classification results revealed that these bacteria encompassed 60 phyla, 183 classes, 431 orders, 702 families, and 1619 genera. There were certain differences in the composition and structure of bacterial communities among different rhizosphere soil samples. According to the richness indices, the performance order among samples was Tonghua water celery > Linjiang large-leaf celery > Linjiang old mountain celery > Tonghua large-leaf celery > Jiangyuan large-leaf celery > Tonghua old mountain celery > Linjiang water celery > artificially cultivated wild large-leaf celery > Huadian large-leaf celery > Huadian small-leaf celery > Dongfeng water celery > Jiangyuan old mountain celery. Among all bacterial communities, Pseudomonadota (37.79–22.48%) had the highest relative abundance across different regions, followed by Acidobacteriota (17.97–13.51%). RDA analysis indicated that soil pH, available phosphorus, available potassium, and alkali-hydrolyzable nitrogen in the celery rhizosphere were the primary factors influencing changes in bacterial communities. Based on the experimental analysis, it was demonstrated that there were differences in rhizosphere soil bacterial community diversity and composition among Tonghua large-leaf celery, Linjiang large-leaf celery, Jiangyuan large-leaf celery, Huadian large-leaf celery, Tonghua old mountain celery, Linjiang old mountain celery, Jiangyuan old mountain celery, Tonghua water celery, Linjiang water celery, Dongfeng water celery, Huadian small-leaf celery, and artificially cultivated wild large-leaf celery in Jilin Province. Full article

Fusarium root rot caused by the Fusarium species complex significantly affects the yield and quality of Angelica sinensis, a valuable medicinal herb. Traditional management primarily relies on chemical fungicides, which have led to pathogen resistance, environmental hazards, and concerns regarding public health and the active components in A. sinensis. This study explores the efficacy of a novel plant-derived biopesticide Shi Chuang Zhi Feng Ning (T1; SCZFN), alongside Bacillus subtilis wettable powder (T2) and a chemical fungicide (T3), in controlling root rot and understanding their impacts on the rhizosphere microbial community and root metabolome. Results of the field experiment demonstrated that treatments T1 and T3 achieved control efficiencies of 73.17% and 75.45%, respectively, significantly outperforming T2 (39.99%) and the control. High-throughput sequencing revealed that all treatments altered the diversity and structure of microbial communities, with T1 and T2 reducing the abundance of taxa linked to root rot, such as Muribaculaceae spp., Humicola spp., Fusarium spp., and Mycochlamys spp. Treatment T1 notably enhanced beneficial bacterial taxa, including Acidobacteria spp., Nitrospira spp., and Pedosphaeraceae spp., involved in carbon cycling and plant growth promotion. Metabolomic analysis identified 39, 105, and 45 differentially expressed metabolites (DEMs) across the treatments, demonstrating T1’s potential to modulate the root metabolome effectively. Further, a correlation analysis demonstrated a stronger correlation between distinct microorganisms with significant influence and DEMs of T1 treatment compared to other treatments. These findings underscore biopesticide SCZFN’s role in enhancing plant health and disease suppression in A. sinensis, providing insights into its biocontrol mechanisms and supporting the development of sustainable disease management strategies in its cultivation. Full article

Crop rotation increases crop yield, improves soil health, and reduces plant disease. However, few studies were conducted on the use of intensive cropping patterns to improve the microenvironment of saline soils. The present study thoroughly evaluated the impact of a three-year maize–peanut–millet crop rotation pattern on the crop yield. The rhizosphere soil of the crop was collected at maturity to assess the effects of crop rotation on the composition and function of microbial communities in different tillage layers (0–20 cm and 20–40 cm) of sandy saline–alkaline soils. After three years of crop rotation, the maize yield and economic benefits rose by an average of 32.07% and 22.25%, respectively, while output/input grew by 10.26%. The pH of the 0–40 cm tillage layer of saline–alkaline soils decreased by 2.36%, organic matter rose by 13.44%–15.84%, and soil-available nutrients of the 0–20 cm tillage layer increased by 11.94%–69.14%. As compared to continuous cropping, crop rotation boosted soil nitrogen and phosphorus metabolism capacity by 8.61%–88.65%. Enrichment of Actinobacteria and Basidiomycota increased crop yield. Crop rotation increases microbial community richness while decreasing diversity. The increase in abundance can diminish competitive relationships between species, boost synergistic capabilities, alter bacterial and fungal community structure, and enhance microbial community function, all of which elevate crop yields. The obtained insights can contribute to achieving optimal management of intensive cultivation patterns and green sustainable development. Full article

Pollutant degradation and heavy-metal resistance may be important features of the rhizobia, making them promising agents for environment cleanup biotechnology. The degradation of phenanthrene, a three-ring polycyclic aromatic hydrocarbon (PAH), by the rhizobial strain Rsf11 isolated from the oil-polluted rhizosphere of alfalfa and the influence of nickel ions on this process were studied. On the basis of whole-genome and polyphasic taxonomy, the bacterium Rsf11 represent a novel species of the genus Neorhizobium, so the name Neorhizobium phenanthreniclasticum sp. nov. was proposed. Analysis of phenanthrene degradation by the Rsf1 strain revealed 1-hydroxy-2-naphthoic acid as the key intermediate and the activity of two enzymes apparently involved in PAH degradation. It was also shown that the nickel resistance of Rsf11 was connected with the extracellular adsorption of metal by EPS. The joint presence of phenanthrene and nickel in the medium reduced the degradation of PAH by the microorganism, apparently due to the inhibition of microbial growth but not due to the inhibition of the activity of the PAH degradation enzymes. Genes potentially involved in PAH catabolism and nickel resistance were discovered in the microorganism studied. N. phenanthreniclasticum strain Rsf11 can be considered as a promising candidate for use in the bioremediation of mixed PAH–heavy-metal contamination. Full article

Arsenic (As) contamination poses significant environmental and health concerns globally, particularly in regions with high exposure levels due to anthropogenic activities. As phytoremediation, particularly through the hyperaccumulator fern Pteris vittata, offers a promising approach to mitigate arsenic pollution. Bacteria and mycorrhizal fungi colonizing P. vittata roots are involved in As metabolism and resistance and plant growth promotion under stressful conditions. A total of 45 bacterial strains were isolated from bulk soil and the rhizosphere of mycorrhizal P. vittata growing in an industrial As-polluted site. Bacteria were characterized by their plant-beneficial traits, tolerance to sodium arsenate and arsenite, and the occurrence of As-resistant genes. This study highlights differences between the culturable fraction of the microbiota associated with the rhizosphere of mycorrhizal P. vittata plants and the bulk soil. Moreover, several strains showing arsenate tolerance up to 600 mM were isolated. All the bacterial strains possessed arsC genes, and about 70% of them showed arrA genes involved in the anaerobic arsenate respiration pathway. The possible exploitation of such bacterial strains in strategies devoted to the assisted phytoremediation of arsenic highlights the importance of such a study in order to develop effective in situ phytoremediation strategies. Full article

This study focused on the isolation, characterization, and evaluation of the antimicrobial and antioxidant activities of a crude extract from Bacillus subtilis isolated from rhizosphere soil. Through biochemical and physiological assessments, followed by whole genome sequencing, the isolate was confirmed as Bacillus subtilis BSP1. We examined the antimicrobial activity of B. subtilis BSP1 metabolites against various pathogenic bacteria and fungi. To enhance its antibacterial efficacy, we optimized the fermentation medium to maximize the secretion of antibacterial agents. Our findings demonstrated that the crude extract exhibited notable antimicrobial properties against various pathogenic bacterial and fungal isolates. The antioxidant test revealed a dose-dependent increase in the extract’s DPPH scavenging activity and reducing power, with an impressive 98.9% DPPH scavenging activity at 30 mg/mL. Importantly, safety assessments indicated a lack of hemolytic activity on human red blood cells, with only 1.3% hemolysis at 100 mg/mL, suggesting its potential suitability for practical applications. In summary, Bacillus subtilis BSP1, isolated from soil, appears to be a promising candidate for antibiotic production. Its significant antimicrobial and antioxidant properties, combined with its safety profile, highlight its potential applications in medicine, agriculture, and biotechnology. Full article

The aim of this study was to develop ready-to-eat vegetable–herb mixes with high nutritional and sensory values as well as good storability. In this regard, the suitability of fresh herbs (peppermint, oregano, green basil, red basil, and parsley) was tested for their use in mixes with fresh-cut iceberg lettuce. Lettuce–herb mixtures were stored for 6 days at 5 °C. The reason for the decrease in the appearance of the salads was the browning of the cut surface of the lettuce, as well as discoloration on the cut herbs. Comparing the storage abilities of the cut herbs, red basil and parsley retained the best appearance for 6 d at 5 °C. A small addition of herbs to fresh-cut iceberg lettuce caused a significant increase (p < 0.05) in the contents of pro-health ingredients such as chlorophyll, carotenoids, L-ascorbic acid, and polyphenols in the mixes. There were large discrepancies in the sensory quality of the mixes, but the highest quality and consumer acceptance were found for salads with parsley (5% and 10%) and red basil (5%). After harvest, the fresh herbs were more contaminated by molds than the iceberg lettuce. Bacterial, yeast, and mold contamination increased during storage, but the rate of mold growth was much lower in the mixes with parsley compared to lettuce alone. In conclusion, the addition of parsley and mint contributed the most to the health-promoting and microbiological properties of iceberg lettuce salads. However, according to sensory evaluation, parsley and red basil contributed the most to improving the acceptability of the product in terms of best taste and shelf life. Full article

Seed treatment with plant growth-promoting bacteria represents the primary strategy to incorporate them into agricultural ecosystems, particularly for crops under extensive management, such as maize. In this study, we evaluated the seed bacterization levels, root colonization patterns, and root competitiveness of a collection of autochthonous Pseudomonas isolates that have demonstrated several plant-probiotic abilities in vitro. Our findings indicate that the seed bacterization level, both with and without the addition of various protectants, is specific to each Pseudomonas strain, including their response to seed pre-hydration. Bacterization kinetics revealed that while certain isolates persisted on seed surfaces for up to 4 days post-inoculation (dpi), others experienced a rapid decline in viability after 1 or 2 dpi. The observed differences in seed bacterization levels were consistent with the root colonization densities observed through confocal microscopy analysis, and with root competitiveness quantified via selective plate counts. Notably, isolates P. protegens RBAN4 and P. chlororaphis subsp. aurantiaca SMMP3 demonstrated effective competition with the natural microflora for colonizing the maize rhizosphere and both promoted shoot and root biomass production in maize assessed at the V3 grown stage. Conversely, P. donghuensis SVBP6 was detected at very low levels in the maize rhizosphere, but still exhibited a positive effect on plant parameters, suggesting a growth-stimulatory effect during the early stages of plant development. In conclusion, there is a considerable strain-specific variability in the maize seed bacterization and survival capacities of Pseudomonas isolates with plant-probiotic traits, with a correlation in their root competitiveness under natural conditions. This variability must be understood to optimize their adoption as inputs for the agricultural system. Our experimental approach emphasizes the critical importance of tailoring seed bacterization treatments for each inoculant candidate, including the selection and incorporation of protective substances. It should not be assumed that all bacterial cells exhibit a similar performance. Full article