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Ecotoxicology and Environmental Safety Sep 2023Cadmium (Cd) removal from soil to reduce Cd accumulation in plants is essential for agroecology, food safety, and human health. Cd enters plants from soil and affects...
Cadmium (Cd) removal from soil to reduce Cd accumulation in plants is essential for agroecology, food safety, and human health. Cd enters plants from soil and affects plant growth and development. Hydrogels can easily combine with Cd, thereby altering its bioavailability in soil. However, few studies have evaluated the effects of hydrogel on the complex phytotoxicity caused by Cd uptake in plants and the microbial community structure. Herein, a new poly (acrylic acid)-grafted starch and potassium humate composite (S/K/AA) hydrogel was added to soil to evaluate its impact on tobacco growth and the soil microenvironment. The results indicate that the addition of S/K/AA hydrogel can significantly improve the biomass, chlorophyll (Chl) content, and photosynthetic capacity of tobacco plants during Cd stress conditions, and decrease Cd concentration, probably by affecting Cd absorption through the expression of Cd absorption transporters (e.g., NRAMP5, NRAMP3, and IRT1). Moreover, the application of S/K/AA hydrogel not only reduced the accumulation of reactive oxygen species (ROS), but also reduced the antioxidant activities of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT), suggesting that S/K/AA hydrogel alleviates Cd toxicity via a non-antioxidant pathway. Notably, we further analyzed the effectiveness of the hydrogel on microbial communities in Cd-contaminated soil and found that it increased the Cd-tolerant microbial community (Arthrobacter, Massilia, Streptomyces), enhancing the remediation ability of Cd-contaminated soil and helping tobacco plants to alleviate Cd toxicity. Overall, our study provides primary insights into how S/K/AA hydrogel affects Cd bioavailability and alleviates Cd toxicity in plants.
Topics: Humans; Cadmium; Biological Availability; Nicotiana; Hydrogels; Arthrobacter
PubMed: 37597289
DOI: 10.1016/j.ecoenv.2023.115361 -
Microorganisms Jul 2022Antimony (Sb) and arsenic (As) are two hazardous metalloid elements, and the biogeochemical cycle of Sb and As can be better understood by studying plant rhizosphere...
Antimony (Sb) and arsenic (As) are two hazardous metalloid elements, and the biogeochemical cycle of Sb and As can be better understood by studying plant rhizosphere microorganisms associated with Sb mine waste. In the current study, samples of three types of mine waste-Sb mine tailing, waste rocks, and smelting slag-and associated rhizosphere microorganisms of adapted plants were collected from Qinglong Sb mine, southwest China. 16S rRNA was sequenced and used to study the composition of the mine waste microbial community. The most abundant phylum in all samples was , followed by , , and . The community composition varied among different mine waste types. was the most abundant microorganism in tailings, was mainly distributed in waste rock, and , , and were mainly present in slag. At the family level, the vast majority of were found in tailings, , , and (Subgroup 1) were mostly found in slag, and and were mainly found in waste rock. and are important taxa for reducing heavy metal(loid) mobility, vegetation restoration, and self-sustaining ecosystem construction on antimony mine waste. The high concentrations of Sb and As reduce microbial diversity.
PubMed: 35893564
DOI: 10.3390/microorganisms10081507 -
Journal of Xenobiotics Jun 2023In the age of industrialization, numerous non-biodegradable pollutants like plastics, HMs, polychlorinated biphenyls, and various agrochemicals are a serious concern.... (Review)
Review
In the age of industrialization, numerous non-biodegradable pollutants like plastics, HMs, polychlorinated biphenyls, and various agrochemicals are a serious concern. These harmful toxic compounds pose a serious threat to food security because they enter the food chain through agricultural land and water. Physical and chemical techniques are used to remove HMs from contaminated soil. Microbial-metal interaction, a novel but underutilized strategy, might be used to lessen the stress caused by metals on plants. For reclaiming areas with high levels of heavy metal contamination, bioremediation is effective and environmentally friendly. In this study, the mechanism of action of endophytic bacteria that promote plant growth and survival in polluted soils-known as heavy metal-tolerant plant growth-promoting (HMT-PGP) microorganisms-and their function in the control of plant metal stress are examined. Numerous bacterial species, such as Arthrobacter, Bacillus, Burkholderia, Pseudomonas, and Stenotrophomonas, as well as a few fungi, such as Mucor, Talaromyces, Trichoderma, and Archaea, such as Natrialba and Haloferax, have also been identified as potent bioresources for biological clean-up. In this study, we additionally emphasize the role of plant growth-promoting bacteria (PGPB) in supporting the economical and environmentally friendly bioremediation of heavy hazardous metals. This study also emphasizes future potential and constraints, integrated metabolomics approaches, and the use of nanoparticles in microbial bioremediation for HMs.
PubMed: 37367495
DOI: 10.3390/jox13020019 -
Biomedicines Sep 2022Recent advances in next-generation sequencing and metagenomic studies have provided insights into the microbial profile of different body sites. However, research on the...
Recent advances in next-generation sequencing and metagenomic studies have provided insights into the microbial profile of different body sites. However, research on the microbial composition of urine is limited, particularly in children. The goal of this study was to optimize and develop reproducible metagenome and virome protocols using a small volume of urine samples collected from healthy children. We collected midstream urine specimens from 40 healthy children. Using the metagenomics shotgun approach, we tested various protocols. Different microbial roots such as Archaea, Bacteria, Eukaryota, and Viruses were successfully identified using our optimized urine protocol. Our data reflected much variation in the microbial fingerprints of children. Girls had significantly higher levels of Firmicutes, whereas boys had significantly higher levels of Actinobacteria. The genus Anaerococcus dominated the urinary bacteriome of healthy girls, with a significant increase in Anaerococcus prevotii, Anaerococcus vaginalis, and Veillonella parvula (p-value < 0.001) when compared with that of boys. An increased relative abundance of Xylanimonas and Arthrobacter, with a significantly high abundance of Arthrobacter sp. FB24 (p-value 0.0028) and Arthrobacter aurescences (p-value 0.015), was observed in boys. The urinary mycobiome showed a significant rise in the genus Malassezia and Malassezia globose fungus (p-value 0.009) in girls, whereas genus Saccharomyces (p-value 0.009) was significantly high in boys. The beta diversity of the urinary mycobiome was found to differ between different age groups. Boys had significantly more Mastadenovirus and Human mastadenovirus-A in their urinary virome than girls. With increasing age, we noticed an increase in the relative abundance of the order Caudovirales. Our optimized protocols allowed us to identify the unique microbes for each sex by using an adequate volume of urine (3−10 mL) to screen for the bacteriome, mycobiome, and virome profiles in the urine of healthy children. To the best of our knowledge, this is the first study to characterize the metagenomics profiles of urine in a healthy pediatric population.
PubMed: 36289674
DOI: 10.3390/biomedicines10102412 -
Applied and Environmental Microbiology Nov 2022Increased drought intensity and frequency exposes soil bacteria to prolonged water stress. While numerous studies reported on behavioral and physiological mechanisms of...
Increased drought intensity and frequency exposes soil bacteria to prolonged water stress. While numerous studies reported on behavioral and physiological mechanisms of bacterial adaptation to water stress, changes in bacterial cell surface properties during adaptation are not well researched. We studied adaptive changes in cell surface hydrophobicity (CSH) after exposure to osmotic (NaCl) and matric stress (polyethylene glycol 8000 [PEG 8000]) for six typical soil bacteria (Bacillus subtilis, Arthrobacter chlorophenolicus, Pseudomonas fluorescens, Novosphingobium aromaticivorans, Rhodococcus erythropolis, and Mycobacterium pallens) covering a wide range of cell surface properties. Additional physicochemical parameters (surface chemical composition, surface charge, cell size and stiffness) of B. subtilis and P. fluorescens were analyzed to understand their possible contribution to CSH development. Changes in CSH caused by osmotic and matric stress depend on strain and stress type. CSH of B. subtilis and P. fluorescens increased with stress intensity, R. erythropolis and exhibited a generally high but constant contact angle, while the response of and depended on growth conditions and stress type. Osmotically driven changes in CSH of B. subtilis and P. fluorescens are accompanied by increasing surface N/C ratio, suggesting an increase in protein concentration within the cell wall. Cell envelope proteins thus presumably control bacterial CSH in two ways: (i) by increases in the relative density of surface proteins due to efflux of cytoplasmic water and subsequent cell shrinkage, and (ii) by destabilization of cell wall proteins, resulting in conformational changes which render the surface more hydrophobic. Changes in precipitation frequency, intensity, and temporal distribution are projected to result in increased frequency and intensity of droughts and heavy rainfall events. Prolonged droughts can promote the development of soil water repellency (SWR); this impacts the infiltration and distribution of water in the soil profile, exposing soil microorganisms to water stress. Exposure to water stress has recently been reported to result in increased cell surface hydrophobicity. However, the mechanism of this development is poorly understood. This study investigates the changes in the physicochemical properties of bacterial cell surfaces under water stress as a possible mechanism of increased surface hydrophobicity. Our results improve understanding of the microbial response to water stress in terms of surface properties, the variations in stress response depending on cell wall composition, and its contribution to the development of SWR.
Topics: Humans; Dehydration; Soil; Surface Properties; Soil Microbiology; Droughts
PubMed: 36226960
DOI: 10.1128/aem.00732-22 -
MBio Jun 2021Plant roots constitute the primary interface between plants and soilborne microorganisms and harbor microbial communities called the root microbiota. Recent studies have...
Plant roots constitute the primary interface between plants and soilborne microorganisms and harbor microbial communities called the root microbiota. Recent studies have demonstrated a significant contribution of plant specialized metabolites (PSMs) to the assembly of root microbiota. However, the mechanistic and evolutionary details underlying the PSM-mediated microbiota assembly and its contribution to host specificity remain elusive. Here, we show that the bacterial genus is predominant specifically in the tobacco endosphere and that its enrichment in the tobacco endosphere is partially mediated by a combination of two unrelated classes of tobacco-specific PSMs, santhopine and nicotine. We isolated and sequenced strains from tobacco roots as well as soils treated with these PSMs and identified genomic features, including but not limited to genes for santhopine and nicotine catabolism, that are associated with the ability to colonize tobacco roots. Phylogenomic and comparative analyses suggest that these genes were gained in multiple independent acquisition events, each of which was possibly triggered by adaptation to particular soil environments. Taken together, our findings illustrate a cooperative role of a combination of PSMs in mediating plant species-specific root bacterial microbiota assembly and suggest that the observed interaction between tobacco and may be a consequence of an ecological fitting process. Host secondary metabolites have a crucial effect on the taxonomic composition of its associated microbiota. It is estimated that a single plant species produces hundreds of secondary metabolites; however, whether different classes of metabolites have distinctive or common roles in the microbiota assembly remains unclear. Here, we show that two unrelated classes of secondary metabolites in tobacco play a cooperative role in the formation of tobacco-specific compositions of the root bacterial microbiota, which has been established as a consequence of independent evolutionary events in plants and bacteria triggered by different ecological effects. Our findings illustrate mechanistic and evolutionary aspects of the microbiota assembly that are mediated by an arsenal of plant secondary metabolites.
Topics: Arthrobacter; Endophytes; Genome, Bacterial; Host Microbial Interactions; Phylogeny; Plant Roots; RNA, Ribosomal, 16S; Rhizosphere; Secondary Metabolism; Sequence Analysis, DNA; Soil Microbiology; Nicotiana
PubMed: 34044592
DOI: 10.1128/mBio.00846-21 -
PeerJ 2022wilt is a kind of soil-borne disease that causes a large reduction in the yield of . The diversity and structure of the soil microbial community are important factors...
wilt is a kind of soil-borne disease that causes a large reduction in the yield of . The diversity and structure of the soil microbial community are important factors affecting the health of . The analysis of the microbial community in the diseased and healthy soils provided a theoretical basis for revealing the pathological mechanism and prevention of wilt disease. In the present study, we sequenced the soil microorganisms from healthy (H), pathology (P) and blank (B) soil samples by Illumina MiSeq. Determined the soil physicochemical properties respectively, analyzed the soil microbial diversity and structure, and constructed single factor co-correlation networks among microbial genera. The results showed that Ascomycota (48.36%), Mortierellomycota (23.06%), Basidiomycota (19.00%), Proteobacteria (31.74%), and Acidobacteria (20.95%) were dominant in the soil. The diversity of healthy soil was significantly greater than that of diseased soil samples (P and B) ( < 0.05). The populations of and significantly increased in the diseased soil sample (P and B) ( < 0.05). (4.74%) and (3.30%) were the most abundant genera in the healthy soil. Total nitrogen (TN), available nitrogen (AN), total potassium (TK), available potassium (AK), and inorganic salt (salt) were significantly correlated with soil microbial communities ( < 0.05). The relationship between fungi and the plant was mostly positive, whereas bacteria showed the opposite trend. In conclusion, the diversity and structure of the soil microbial community were closely related to the health level of . and affect the severity of wilt disease, while and are the important indicators for maintaining the health of . Moreover, environmental factors greatly affect the abundance and formation of soil microbial community. The interactions in microbial communities also influence the healthy growth of .
Topics: Soil; Rhizosphere; Fritillaria; Microbiota; Ascomycota; Fusarium; Health Status
PubMed: 35127284
DOI: 10.7717/peerj.12778 -
Foods (Basel, Switzerland) Nov 2023The microbial community in donkey milk and its impact on the nutritional value of donkey milk are still unclear. We evaluated the effects of different lactation stages...
The microbial community in donkey milk and its impact on the nutritional value of donkey milk are still unclear. We evaluated the effects of different lactation stages on the composition and function of donkey milk microbiota. The milk samples were collected at 1, 30, 60, 90, 120, 150, and 180 days post-delivery. The result showed that the microbial composition and functions in donkey milk were significantly affected by different lactation stages. The dominant bacterial phyla in donkey milk are (60%) and (22%). (39%), (4%), and (2%) were the predominant bacterial genera detected in all milk samples. In the mature milk, the abundance of lactic acid bacteria (7%) was higher. (5%) and (3%) were more plentiful in milk samples from middle and later lactation stages (90-180 d). Furthermore, the pathogens and and thermoduric bacteria , , and were also detected. Donkey milk is rich in beneficial bacteria and also poses a potential health risk. The above findings have improved our understanding of the composition and function changes of donkey milk microbiota, which is beneficial for the rational utilization of donkey milk.
PubMed: 38231735
DOI: 10.3390/foods12234272 -
International Journal of Environmental... Jul 2022In response to the problems of the poor degradability and mechanical properties of liquid mulch, natural non-toxic polymer compound corn starch and sodium alginate were...
In response to the problems of the poor degradability and mechanical properties of liquid mulch, natural non-toxic polymer compound corn starch and sodium alginate were used to prepare fully biodegradable liquid mulch. The preparation conditions of the mulch were optimized, and the mechanical properties of the mulch and the changes in the microbial community in soil with the mulch degradation were analyzed. The corn-starch-sodium-alginate-based liquid mulch film had an optimum performance at a tensile strength of 0.145 MPa and an elongation at a break of 16.05%, which was attained by adding 33.33% sodium alginate, 50% glycerol 22 and 4% citric acid to corn starch after moist heat modification. Fourier transform infrared spectroscopy analysis showed that the -COOH in sodium alginate could interact with the -OH in starch and glycerol through hydrogen bonding, thus, resulting in a denser structure and better mechanical properties of the liquid mulch as a non-crystalline material. The soil burial degradation study of mulch revealed that corn-starch-sodium-alginate-based liquid mulch degraded completely at 25 days macroscopically, and mulch degradation increased soil organic matter content. Microbial kinetic analysis showed that the abundance and diversity of the bacterial community decreased with the degradation of the mulch, which was conducive to the optimization of the bacterial community structure and function. of the class became the dominant microorganism, and its abundance increased by 16.48-times at 14 days of mulch degradation compared with that before degradation, and phylum (14 days) decreased by 99.33%. The abundance of fungal communities was elevated in relation to the main functional microorganisms involved in liquid mulch degradation, with and of the phylum being the most active at the early stage of mulch degradation (7 days), and the relative abundance of was significantly elevated at the late stage of mulch degradation (14 days), which increased by 13.32%. This study provides important support for the green and sustainable development of modern agriculture.
Topics: Alginates; Glycerol; Kinetics; Sodium; Soil; Soil Microbiology; Starch; Zea mays
PubMed: 35886488
DOI: 10.3390/ijerph19148631 -
Rhizospheric Revealed Antifungal and Plant-Growth-Promoting Activities under Controlled Environment.Plants (Basel, Switzerland) Jul 2022has large habitats and can be isolated from terrestrial soil, rhizospheres of plant roots, and marine sediments. produce several bioactive secondary metabolites with...
has large habitats and can be isolated from terrestrial soil, rhizospheres of plant roots, and marine sediments. produce several bioactive secondary metabolites with antibacterial, antifungal, and antiviral properties. In this study, some strains were isolated from the rhizosphere zone of four different plant species: rosemary, acacia, strawberry, and olive. The antagonistic activity of all isolates was screened in vitro against and . Isolates with the strongest bioactivity potential were selected and molecularly identified as sp., , and . The growth-promoting activity of the selected isolates was in vivo evaluated on tomato plants and for disease control against . The results demonstrated that all bacterized plants with the studied isolates were able to promote the tomato seedlings' growth, showing high values of ecophysiological parameters. In particular, the bacterized seedlings with sp. and showed low disease incidence of infection (0.3% and 0.2%, respectively), whereas those bacterized with showed a moderate disease incidence (7.6%) compared with the positive control (36.8%). In addition, the ability of the studied to produce extracellular hydrolytic enzymes was verified. The results showed that was able to produce chitinase, glucanase, and protease, whereas sp. and produced amylase and pectinase at high and moderate levels, respectively. This study highlights the value of the studied isolates in providing bioactive metabolites and extracellular hydrolytic enzymes, indicating their potential application as fungal-biocontrol agents.
PubMed: 35890505
DOI: 10.3390/plants11141872