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Environmental Pollution (Barking, Essex... Dec 2023The use of bioretention cells as a stormwater control measure allows stormwater runoff to be collected and filtered, effectively removing microplastics and other...
The use of bioretention cells as a stormwater control measure allows stormwater runoff to be collected and filtered, effectively removing microplastics and other pollutants from stormwater. This study investigated the effect of polyethylene microplastics (PE-MPs) retention on the bioretention cell, in terms of denitrification performance and microbial community structure. Four PE-MP exposures were compared at different concentrations of 0, 250, 500 and 1000 mg/L under alternating dry and wet period conditions. Results showed that the removal efficiency reduced by 14.99%, 28.37% and 18.59% with PE-MP concentrations of 250, 500 and 1000 mg/L. The NO-N removal efficiency increased by 36.19%, 20.19% and 35.39%. After 8 days of dry conditions, the NO-N removal efficiencies of the bioretention cells were reduced by 36.66%, 46.86% and 31.11% compared to those after 2 days of dry conditions. Microbial sequencing results indicated that the accumulation of PE-MPs changed the microbial community structure within the bioretention cell filler material, promoting the growth of bacteria such as Actinobacteria, Bacteroidetes and Firmicutes. Furthermore, PE-MPs reduced the relative abundance of nitrifying bacteria (e.g. Nitrospira) within the bioretention cell and promoted denitrifying bacteria (e.g. Dechloromonas and Hydrogenophaga), along with numerous other genera such as Azotobacter and Nocardia.
Topics: Denitrification; Plastics; Polyethylene; Microplastics; Nitrogen; Rain; Bacteria
PubMed: 37778494
DOI: 10.1016/j.envpol.2023.122655 -
Plant Physiology and Biochemistry : PPB Oct 2023The addition of biochars and nanoparticles with adsorbed Azotobacter vinelandii and Bacillus megaterium alleviated damage from Fusarium infection in both tomato (Solanum...
The addition of biochars and nanoparticles with adsorbed Azotobacter vinelandii and Bacillus megaterium alleviated damage from Fusarium infection in both tomato (Solanum lycopersicum) and watermelon (Citrullus lanatus) plants. Tomato and watermelon plants were grown in greenhouse for 28 and 30 days (respectively) and were treated with either nanoparticles (chitosan-coated mesoporous silica or nanoclay) or varying biochars (biochar produced by pyrolysis, gasification and pyrogasification). Treatments with nanoparticles and biochars were applied in two variants - with or without adsorbed plant-growth promoting bacteria (PGPR). Chitosan-coated mesoporous silica nanoparticles with adsorbed bacteria increased chlorophyll content in infected tomato and watermelon plants (1.12 times and 1.63 times, respectively) to a greater extent than nanoclay with adsorbed bacteria (1.10 times and 1.38 times, respectively). However, the impact on other endpoints (viability of plant cells, phosphorus and nitrogen content, as well antioxidative status) was species-specific. In all cases, plants treated with adsorbed bacteria responded better than plants without bacteria. For example, the content of antioxidative compounds in diseased watermelon plants increased nearly 46% upon addition of Aries biochar and by approximately 52% upon addition of Aries biochar with adsorbed bacteria. The overall effect on disease suppression was due to combination of the antifungal effects of both nanoparticles (and biochars) and plant-growth promoting bacteria. These findings suggest that nanoparticles or biochars with adsorbed PGPR could be viewed as a novel and sustainable solution for management of Fusarium wilt.
Topics: Solanum lycopersicum; Fusarium; Citrullus; Chitosan; Bacteria; Nanoparticles; Silicon Dioxide; Plant Diseases
PubMed: 37778113
DOI: 10.1016/j.plaphy.2023.108052 -
The ISME Journal Dec 2023Nitrogen is a limiting nutrient for degraders function in hydrocarbon-contaminated environments. Biological nitrogen fixation by diazotrophs is a natural solution for...
Nitrogen is a limiting nutrient for degraders function in hydrocarbon-contaminated environments. Biological nitrogen fixation by diazotrophs is a natural solution for supplying bioavailable nitrogen. Here, we determined whether the diazotroph Azotobacter chroococcum HN can provide nitrogen to the polycyclic aromatic hydrocarbon-degrading bacterium Paracoccus aminovorans HPD-2 and further explored the synergistic interactions that facilitate pyrene degradation in nitrogen-deprived environments. We found that A. chroococcum HN and P. aminovorans HPD-2 grew and degraded pyrene more quickly in co-culture than in monoculture. Surface-enhanced Raman spectroscopy combined with N stable isotope probing (SERS - N SIP) demonstrated that A. chroococcum HN provided nitrogen to P. aminovorans HPD-2. Metabolite analysis and feeding experiments confirmed that cross-feeding occurred between A. chroococcum HN and P. aminovorans HPD-2 during pyrene degradation. Transcriptomic and metabolomic analyses further revealed that co-culture significantly upregulated key pathways such as nitrogen fixation, aromatic compound degradation, protein export, and the TCA cycle in A. chroococcum HN and quorum sensing, aromatic compound degradation and ABC transporters in P. aminovorans HPD-2. Phenotypic and fluorescence in situ hybridization (FISH) assays demonstrated that A. chroococcum HN produced large amounts of biofilm and was located at the bottom of the biofilm in co-culture, whereas P. aminovorans HPD-2 attached to the surface layer and formed a bridge-like structure with A. chroococcum HN. This study demonstrates that distinct syntrophic interactions occur between A. chroococcum HN and P. aminovorans HPD-2 and provides support for their combined use in organic pollutant degradation in nitrogen-deprived environments.
Topics: Nitrogen; In Situ Hybridization, Fluorescence; Nitrogen Fixation; Pyrenes
PubMed: 37775536
DOI: 10.1038/s41396-023-01522-w -
Microorganisms Sep 2023Genomic DNA has high phosphate content; therefore, monoploid prokaryotes need an external phosphate source or an internal phosphate storage polymer for replication and...
One Advantage of Being Polyploid: Prokaryotes of Various Phylogenetic Groups Can Grow in the Absence of an Environmental Phosphate Source at the Expense of Their High Genome Copy Numbers.
Genomic DNA has high phosphate content; therefore, monoploid prokaryotes need an external phosphate source or an internal phosphate storage polymer for replication and cell division. For two polyploid prokaryotic species, the halophilic archaeon and the cyanobacterium PCC 6803, it has been reported that they can grow in the absence of an external phosphate source by reducing the genome copy number per cell. To unravel whether this feature might be widespread in and typical for polyploid prokaryotes, three additional polyploid prokaryotic species were analyzed in the present study, i.e., the alphaproteobacterium , the gammaproteobacterium , and the haloarchaeon Polyploid cultures were incubated in the presence and in the absence of external phosphate, growth was recorded, and genome copy numbers per cell were quantified. Limited growth in the absence of phosphate was observed for all three species. Phosphate was added to phosphate-starved cultures to verify that the cells were still viable and growth-competent. Remarkably, stationary-phase cells grown in the absence or presence of phosphate did not become monoploid but stayed oligoploid with about five genome copies per cell. As a negative control, it was shown that monoploid cultures did not exhibit any growth in the absence of phosphate. Taken together, all five polyploid prokaryotic species that have been characterized until now can grow in the absence of environmental phosphate by reducing their genome copy numbers, indicating that cell proliferation outperforms other evolutionary advantages of polyploidy.
PubMed: 37764113
DOI: 10.3390/microorganisms11092267 -
Frontiers in Plant Science 2023The excessive use of chemical fertilizers is deteriorating both the environment and soil, making it a big challenge faced by sustainable agriculture. To assist the...
The excessive use of chemical fertilizers is deteriorating both the environment and soil, making it a big challenge faced by sustainable agriculture. To assist the efforts for the solution of this burning issue, nine different potential native strains of plant growth-promoting bacteria (PGPB) namely, SA-1(, SA-5 (,SA-7(), BH-1(), BH-7(), BH-8(), BA-3(), BA-6(), and BA-7() were isolated that were characterized morphologically, biochemically and molecularly on the basis of 16S rRNA sequencing. Furthermore, the capability of indigenous PGPB in wheat (, Chakwal-50) under control, DAP+FYM, SA, BH, BA, DAP+ FYM + SA, DAP+FYM+ BH and DAP+FYM+ BA treatments was assessed in a randomized complete block design (RCBD). The results of the study showed that there was a significant increase in plant growth, nutrients, quality parameters, crop yield, and soil nutrients at three depths under SA, BH, and BA in combination with DAP+FYM. Out of all these treatments, DAP+ FYM + BA was found to be the most efficient for wheat growth having the highest 1000-grain weight of 55.1 g. The highest values for plant height, no. of grains/spike, spike length, shoot length, root length, shoot dry weight, root dry weight, 1000 grain weight, biological yield, and economic yield were found to be 90.7 cm, 87.7 cm, 7.20 cm, 53.5 cm, 33.5 cm, 4.87 g, 1.32 g, 55.1 g, 8209 kg/h, and 4572 kg/h, respectively, in the DAP+FYM+BA treatment. The DAP+FYM+BA treatment had the highest values of TN (1.68 µg/mL), P (0.38%), and K (1.33%). Likewise, the value of mean protein (10.5%), carbohydrate (75%), lipid (2.5%), and available P (4.68 ppm) was also highest in the DAP+FYM+BA combination. C:P was found to be significantly highest (20.7) in BA alone but was significantly lowest (11.9) in DAP+FYM+BA. Hence, the integration of strains BA-3, BA-5, and BA-7 in fertilizers can be regarded as the most suitable choice for agricultural growth in the sub-mountainous lower region of AJK. This could serve as the best choice for sustainable wheat growth and improved soil fertility with lesser impacts on the environment.
PubMed: 37727857
DOI: 10.3389/fpls.2023.1232271 -
Microbiology Spectrum Sep 2023Biological nitrogen fixation, the microbial reduction of atmospheric nitrogen to bioavailable ammonia, represents both a major limitation on biological productivity and...
Biological nitrogen fixation, the microbial reduction of atmospheric nitrogen to bioavailable ammonia, represents both a major limitation on biological productivity and a highly desirable engineering target for synthetic biology. However, the engineering of nitrogen fixation requires an integrated understanding of how the gene regulatory dynamics of host diazotrophs respond across sequence-function space of its central catalytic metalloenzyme, nitrogenase. Here, we interrogate this relationship by analyzing the transcriptome of engineered with a phylogenetically inferred ancestral nitrogenase protein variant. The engineered strain exhibits reduced cellular nitrogenase activity but recovers wild-type growth rates following an extended lag period. We find that expression of genes within the immediate nitrogen fixation network is resilient to the introduced nitrogenase sequence-level perturbations. Rather the sustained physiological compatibility with the ancestral nitrogenase variant is accompanied by reduced expression of genes that support trace metal and electron resource allocation to nitrogenase. Our results spotlight gene expression changes in cellular processes adjacent to nitrogen fixation as productive engineering considerations to improve compatibility between remodeled nitrogenase proteins and engineered host diazotrophs. IMPORTANCE is a key model bacterium for the study of biological nitrogen fixation, an important metabolic process catalyzed by nitrogenase enzymes. Here, we demonstrate that compatibilities between engineered strains and nitrogenase variants can be modulated at the regulatory level. The engineered strain studied here responds by adjusting the expression of proteins involved in cellular processes adjacent to nitrogen fixation, rather than that of nitrogenase proteins themselves. These insights can inform future strategies to transfer nitrogenase variants to non-native hosts.
PubMed: 37702481
DOI: 10.1128/spectrum.02815-23 -
Plants (Basel, Switzerland) Aug 2023Calcareous soil had sufficient phosphorus and potassium (PK) in different forms due to the high contents of PK-bearing minerals; however, the available PK state was...
Compost and Phosphorus/Potassium-Solubilizing Fungus Effectively Boosted Quinoa's Physio-Biochemical Traits, Nutrient Acquisition, Soil Microbial Community, and Yield and Quality in Normal and Calcareous Soils.
Calcareous soil had sufficient phosphorus and potassium (PK) in different forms due to the high contents of PK-bearing minerals; however, the available PK state was reduced due to its PK-fixation capacity. Compost, coupled with high PK solubilization capacity microbes, is a sustainable solution for bioorganic fertilization of plants grown in calcareous soil. A 2-year field experiment was conducted to investigate the effect of compost (20 t ha) with through soil drenching (C-AN) along with partial substitution of PK fertilization on quinoa performance in normal and calcareous soils. Treatments included PK (72 kg PO ha + 60 kg KO ha as conventional rate), PK+C-AN, PK+C-AN, PK+C-AN, PK+C-AN, and only C-AN in normal and calcareous soils. Results showed that C-AN and reduced PK fertilization (up to 75 or 50%) increased photosynthetic pigments and promoted nutrient acquisition in quinoa grown in calcareous soil. Reduced PK fertilization to 75 or 50% plus C-AN in calcareous soil increased osmoprotectants, nonenzymatic antioxidants, and DPPH scavenging activity of quinoa's leaves compared to the PK+C-AN treatment. The integrative application of high PK levels and C-AN enhanced the quinoa's seed nutritional quality (i.e., lipids, carbohydrates, mineral contents, total phenolics, total flavonoids, half maximal inhibitory concentration, and antiradical power) in calcareous soil. At reduced PK fertilization (up to 75 or 50%), application of compost with through soil drenching increased plant dry weight by 38.7 or 53.2%, hectoliter weight by 3.0 or 2.4%, seed yield by 49.1 or 39.5%, and biological yield by 43.4 or 33.6%, respectively, compared to PK+C-AN in calcareous soil. The highest P-solubilizing microorganism's population was found at PK+C-AN in calcareous soil, while the highest sp. population was observed under high PK levels + C-AN in normal soil. Our study recommends that compost with as a bioorganic fertilization treatment can partially substitute PK fertilization and boost quinoa's tolerance to salt calcareous-affected soil.
PubMed: 37687318
DOI: 10.3390/plants12173071 -
Plants (Basel, Switzerland) Aug 2023The problem of phosphorus and nitrogen deficiency in agricultural soils has been solved by adding chemical fertilizers. However, their excessive use and their...
The problem of phosphorus and nitrogen deficiency in agricultural soils has been solved by adding chemical fertilizers. However, their excessive use and their accumulation have only contributed to environmental contamination. Given the high content of nutrients in biosolids collected from a food industry waste treatment plant, their use as fertilizers was investigated in plants grown in sandy loam soil collected from a semi-desert area. These biosolids contained insoluble phosphorus sources; therefore, given the ability of to solubilize phosphates, this strain was incorporated into the study. In vitro, the suitable conditions for the growth of plants were determined by using biosolids as a fertilizer and as a plant-growth-promoting microorganism; in vitro, the ability of to solubilize phosphates, fix nitrogen, and produce indole acetic acid, a phytohormone that promotes root formation, was also evaluated. At the greenhouse stage, the plants fertilized with biosolids at concentrations of 15 and 20% (/) and inoculated with favored the development of bending strength plants, which was observed on the increased stem diameter (>13.5% compared with the negative control and >7.4% compared with the positive control), as well as a better absorption of phosphorus and nitrogen, the concentration of which increased up to 62.8% when compared with that in the control treatments. The interactions between plants and were observed via scanning electron microscopy. The application of biosolids and in plants grown in greenhouses presented better development than when plants were treated with a chemical fertilizer. The enhanced plant growth was attributed to the increase in root surface area.
PubMed: 37687299
DOI: 10.3390/plants12173052 -
Stress Biology Aug 2022Rice sheath blight pathogen, Rhizoctonia solani, produces numerous sclerotia to overwinter. As a rich source of nutrients in the soil, sclerotia may lead to the change...
Rice sheath blight pathogen, Rhizoctonia solani, produces numerous sclerotia to overwinter. As a rich source of nutrients in the soil, sclerotia may lead to the change of soil microbiota. For this purpose, we amended the sclerotia of R. solani in soil and analyzed the changes in bacterial microbiota within the soil at different time points. At the phyla level, Proteobacteria, Acidobacteria, Bacteroidetes, Actinobacteria, Chloroflexi and Firmicutes showed varied abundance in the amended soil samples compared to those in the control. An increased abundance of ammonia-oxidizing bacterium (AOB) Nitrosospira and Nitrite oxidizing bacteria (NOB) i.e., Nitrospira was observed, where the latter is reportedly involved in the nitrifier denitrification. Moreover, Thiobacillus, Gemmatimonas, Anaeromyxobacter and Geobacter, the vital players in denitrification, NO reduction and reductive nitrogen transformation, respectively, depicted enhanced abundance in R. solani sclerotia-amended samples. Furthermore, asymbiotic nitrogen-fixing bacteria, notably, Azotobacter as well as Microvirga and Phenylobacterium with nitrogen-fixing potential also enriched in the amended samples compared to the control. Plant growth promoting bacteria, such as Kribbella, Chitinophaga and Flavisolibacter also enriched in the sclerotia-amended soil. As per our knowledge, this study is of its kind where pathogenic fungal sclerotia activated microbes with a potential role in N transformation and provided clues about the ecological functions of R. solani sclerotia on the stimulation of bacterial genera involved in different processes of N-cycle within the soil in the absence of host plants.
PubMed: 37676387
DOI: 10.1007/s44154-022-00049-y -
Applied Microbiology and Biotechnology Nov 2023The continuous obstacles of cropping cause severe economic loss, which seriously threaten agricultural sustainable development. In addition, managing excess waste, such...
The continuous obstacles of cropping cause severe economic loss, which seriously threaten agricultural sustainable development. In addition, managing excess waste, such as potato peel and mineral waste residues, is a vital burden for industry and agriculture. Therefore, we explored the feasibility of reductive soil disinfestation (RSD) with potato peel and amendment with iron mineral waste residues for the production of Fritillaria thunbergii, which is vulnerable to continuous obstacles. In this study, the influences of iron mineral, RSD with different organic maters, as well as the combined effects of iron mineral and RSD on Fritillaria rhizosphere soil physicochemical properties, microbial communities, and Fritillaria production were investigated. The results revealed that the RSD treatments with potato peel significantly reduced the soil salinity and increased the soil pH, microbial activity, organic matter, and the contents of K and Ca. RSD with potato peel also significantly thrived of the beneficial microbes (Bacillus, Azotobacter, Microvirga, and Chaetomium), and down-regulated potential plant pathogens. RSD with potato peel significantly promoted F. thunbergii yield and quality. Moreover, the combined effects of RSD and iron mineral amendment further enhanced soil health, improved microbial community composition, and increased the yield and peimisine content of F. thunbergii by 24.2% and 49.3%, respectively. Overall, our results demonstrated that RSD with potato peel and amendment with iron mineral waste residues can efficiently improve soil fertility, modify the microbial community, and benefit for both the sustainable production of F. thunbergii and the management of waste. KEY POINTS: • RSD increases soil pH, organic matter, microbial activity, and mineral content • RSD with potato peel enriches beneficial microbes and decreases plant pathogens • PP + Fe treatment increases Fritillaria yield by 24.2% and peimisine content by 49.3.
PubMed: 37676290
DOI: 10.1007/s00253-023-12766-z