Soil enzyme response to bisphenol F contamination in the soil bioaugmented using bacterial and mould fungal consortium

Soil phosphorus transformation and plant uptake driven by phosphate-solubilizing microorganisms

Phosphorus (P) is an important nutrient for plants, and a lack of available P greatly limits plant growth and development. Phosphate-solubilizing microorganisms (PSMs) significantly enhance the ability of plants to absorb and utilize P, which is important for improving plant nutrient turnover and yield. This article summarizes and analyzes how PSMs promote the absorption and utilization of P nutrients by plants from four perspectives: the types and functions of PSMs, phosphate-solubilizing mechanisms, main functional genes, and the impact of complex inoculation of PSMs on plant P acquisition. This article reviews the physiological and molecular mechanisms of phosphorus solubilization and growth promotion by PSMs, with a focus on analyzing the impact of PSMs on soil microbial communities and its interaction with root exudates. In order to better understand the ability of PSMs and their role in soil P transformation and to provide prospects for research on PSMs promoting plant P absorption. PSMs mainly activate insoluble P through the secretion of organic acids, phosphatase production, and mycorrhizal symbiosis, mycorrhizal symbiosis indirectly activates P via carbon exchange. PSMs can secrete organic acids and produce phosphatase, which plays a crucial role in soil P cycling, and related genes are involved in regulating the P-solubilization ability. This article reviews the mechanisms by which microorganisms promote plant uptake of soil P, which is of great significance for a deeper understanding of PSM-mediated soil P cycling, plant P uptake and utilization, and for improving the efficiency of P utilization in agriculture.

Bisphenols-A Threat to the Natural Environment

Negative public sentiment built up around bisphenol A (BPA) follows growing awareness of the frequency of this chemical compound in the environment. The increase in air, water, and soil contamination by BPA has also generated the need to replace it with less toxic analogs, such as Bisphenol F (BPF) and Bisphenol S (BPS). However, due to the structural similarity of BPF and BPS to BPA, questions arise about the safety of their usage. The toxicity of BPA, BPF, and BPS towards humans and animals has been fairly well understood. The biodegradability potential of microorganisms towards each of these bisphenols is also widely recognized. However, the scale of their inhibitory pressure on soil microbiomes and soil enzyme activity has not been estimated. These parameters are extremely important in determining soil health, which in turn also influences plant growth and development. Therefore, in this manuscript, knowledge has been expanded and systematized regarding the differences in toxicity between BPA and its two analogs. In the context of the synthetic characterization of the effects of bisphenol permeation into the environment, the toxic impact of BPA, BPF, and BPS on the microbiological and biochemical parameters of soils was traced. The response of cultivated plants to their influence was also analyzed.

Effects of Tebuconazole Application on Soil Microbiota and Enzymes

Identification of pesticide impact on the soil microbiome is of the utmost significance today. Diagnosing the response of bacteria to tebuconazole, used for plant protection, may help isolate the most active bacteria applicable in the bioaugmentation of soils contaminated with this preparation. Bearing in mind the above, a study was undertaken to test the effect of tebuconazole on the diversity of bacteria at all taxonomic levels and on the activity of soil enzymes. It was conducted by means of standard and metagenomic methods. Its results showed that tebuconazole applied in doses falling within the ranges of good agricultural practice did not significantly disturb the biological homeostasis of soil and did not diminish its fertility. Tebuconazole was found to stimulate the proliferation of organotrophic bacteria and fungi, and also the activities of soil enzymes responsible for phosphorus, sulfur, and carbon metabolism. It did not impair the activity of urease responsible for urea hydrolysis, or cause any significant changes in the structure of bacterial communities. All analyzed soil samples were mainly populated by bacteria from the phylum Proteobacteria, Actinobacteria, Firmicutes, Gemmatimonadetes, Acidobacteria, Planctomycetes, and Chloroflexi. Bacteria from the genera Kaistobacter, Arthrobacter, and Streptomyces predominated in the soils contaminated with tebuconazole, whereas these from the Gemmata genus were inactivated by this preparation.

Isolation, characterization and application of the epoxiconazole-degrading strain Pseudomonas sp. F1 in a soil-vegetable system

Epoxiconazole (EPX) has a long half-life in soil and causes various toxicological effects in both the ecosystem and mammals. In this study, eight strains of bacteria capable of degrading EPX were isolated from pesticide-contaminated soil, with strain F1 showing the best effect. This strain was identified as Pseudomonas sp. by 16S rRNA gene sequencing and physiological-biochemical analyses. Our results indicated that strain F1 has a high capacity to degrade EPX, removing 92.1% of EPX within 6 days. The temperature and pH were the two most important environmental factors affecting EPX degradation, followed by substrate concentration and inoculum dose. In addition, strain F1 has a high capacity to promote EPX degradation in soils, with a lower t_1/2 value (2.64 d) in F1-inoculated soil compared to the control (t_1/2 = 96.3 d) without strain F1. The strain could efficiently colonize rhizosphere soil and enhance degradation of EPX, leading to a significant decrease in the accumulation and translocation of EPX in vegetables, thereby alleviating the effects of EPX-induced stress on plants. Moreover, we observed that strain F1-gfp was able to colonize the roots, stems and leaves of Brassica rapa var. chinensis. Such colonization may play a role in the efficient degradation of EPX within plants. To our knowledge, this is the first study to demonstrate biodegradation of EPX in a soil-vegetable system using an EPX-degrading bacterium. This study indicates that strain F1 is a promising candidate for simultaneous bioremediation of soil contaminated with EPX and safe food production.

Proper irrigation amount for eggplant cultivation in a solar greenhouse improved plant growth, fruit quality and yield by influencing the soil microbial community and rhizosphere environment

Water scarcity is a worldwide problem, and in order to obtain plenty of production, agricultural irrigation water accounts for a large portion. Many studies have shown that the interaction of root microorganisms and soil can promote crop growth. Developing ways to reduce irrigation to maintain soil fertility and ensure crop yield by regulating the root microenvironment is an important research goal. Here, we developed a reasonable irrigation plan for eggplant cultivation in a solar greenhouse. The maximum theoretical amount of water demand during eggplant planting obtained from a previous study was used as the control (CK), and the irrigation in the treatments was reduced by 10, 20 and 30% relative to this amount. The 10% irrigation reduction treatment (T1) significantly improved soil nutrients and increased soil catalase, urease and alkaline phosphatase activities (p < 0.05). Further analysis of rhizosphere microorganisms revealed the highest richness and diversity of the microbial community under the T1 treatment, with Bacilli as the most abundant bacteria and Aspergillaceae as the most abundant fungi and lower relative abundances of Chloroflexi and Acidobacteria (p < 0.05). Changes in microbial community structure under the influence of different irrigation treatments resulted in improvements in rhizosphere N cycling and nutrient catabolism. The plant–microbe interactions led to significant increases in eggplant plant height, root vigour, root surface area, leaf chlorophyll a, leaf net photosynthetic rate, water use efficiency, transpiration rate, and stomatal conductance under the T1 treatment compared to the CK treatment; soluble sugar, soluble protein and free amino acid contents in eggplant fruit increased by 10.8, 12.3 and 6.7%, respectively; and yield increased by 3.9%. Our research proved that the 10% irrigation reduction treatment (T1) could improve microbial community richness and fruit yield, which would improve irrigation efficiency and cost reduction in agriculture.

Calorific Value of Festuca rubra Biomass in the Phytostabilization of Soil Contaminated with Nickel, Cobalt and Cadmium Which Disrupt the Microbiological and Biochemical Properties of Soil

The choice of optimal plant species for phytoremediation and organic fertilization plays an important role in stabilizing the functions of soils contaminated with heavy metals. The influence of nickel, cobalt and cadmium on the biomass yield and calorific value of Festuca rubra, heavy metal concentrations in soil and plants and the microbiological, biochemical and physicochemical proprieties of soil were analyzed in a pot experiment. The tolerance index (TI) describing Festuca rubra’s ability to tolerate heavy metals, as well as the translocation (TF), accumulation (AF) and bioaccumulation (BF) factors of heavy metals in Festuca rubra were calculated. The experiment was conducted in two series: In soil fertilized and not fertilized with compost. Nickel and cobalt significantly inhibited the growth and development of Festuca rubra. The experiment demonstrated that this plant species can be grown on soil contaminated with heavy metals. Festuca rubra contained on average 46.05% C, 34.59% O, 5.91% H, 3.49% N, 0.19% S and 9.76% ash. Festuca rubra has a stable calorific value which is not affected by heavy metals; therefore, biomass harvested from heavy metal-polluted soil can be used for energy generation. The calorific value of Festuca rubra ranged from 15.924 to 16.790 MJ kg−1 plant d.m., and the heat of combustion from 17.696 to 18.576 MJ kg−1. It has a stable calorific value which is not affected by heavy metals, therefore biomass harvested from heavy metal-polluted soil can be used for energy generation. Festuca rubra is particularly useful for the phytostabilization of soil contaminated with cadmium and cobalt. Compost minimizes the adverse effects of heavy metal pollution on the microbiological, biochemical and physicochemical properties of soil.

Microbial Consortia Are Needed to Degrade Soil Pollutants

Soil pollution is one of the most serious environmental problems globally due to the weak self-purification ability, long degradation time, and high cost of cleaning soil pollution. The pollutants in the soil can be transported into the human body through water or dust, causing adverse effects on human health. The latest research has shown that the clean-up of soil pollutants through microbial consortium is a very promising method. This review provides an in-depth discussion on the efficient removal, bio-adsorption, or carbonated precipitation of organic and inorganic pollutants by the microbial consortium, including PAHs, BPS, BPF, crude oil, pyrene, DBP, DOP, TPHP, PHs, butane, DON, TC, Mn, and Cd. In view of the good degradation ability of the consortium compared to single strains, six different synergistic mechanisms and corresponding microorganisms are summarized. The microbial consortium obtains such activities through enhancing synergistic degradation, reducing the accumulation of intermediate products, generating the crude enzyme, and self-regulating, etc. Furthermore, the degradation efficiency of pollutants can be greatly improved by adding chemical materials such as the surfactants Tween 20, Tween 80, and SDS. This review provides insightful information regarding the application of microbial consortia for soil pollutant removal.

Bisphenol A-A Dangerous Pollutant Distorting the Biological Properties of Soil

Bisphenol A (BPA), with its wide array of products and applications, is currently one of the most commonly produced chemicals in the world. A narrow pool of data on BPA–microorganism–plant interaction mechanisms has stimulated the following research, the aim of which has been to determine the response of the soil microbiome and crop plants, as well as the activity of soil enzymes exposed to BPA pressure. A range of disturbances was assessed, based on the activity of seven soil enzymes, an abundance of five groups of microorganisms, and the structural diversity of the soil microbiome. The condition of the soil was verified by determining the values of the indices: colony development (CD), ecophysiological diversity (EP), the Shannon–Weaver index, and the Simpson index, tolerance of soil enzymes, microorganisms and plants (TI_BPA), biochemical soil fertility (BA₂₁), the ratio of the mass of aerial parts to the mass of plant roots (PR), and the leaf greenness index: Soil and Plant Analysis Development (SPAD). The data brought into sharp focus the adverse effects of BPA on the abundance and ecophysiological diversity of fungi. A change in the structural composition of bacteria was noted. Bisphenol A had a more beneficial effect on the Proteobacteria than on bacteria from the phyla Actinobacteria or Bacteroidetes. The microbiome of the soil exposed to BPA was numerously represented by bacteria from the genus Sphingomonas. In this object pool, the highest fungal OTU richness was achieved by the genus Penicillium, a representative of the phylum Ascomycota. A dose of 1000 mg BPA kg⁻¹ d.m. of soil depressed the activity of dehydrogenases, urease, acid phosphatase and β-glucosidase, while increasing that of alkaline phosphatase and arylsulfatase. Spring oilseed rape and maize responded significantly negatively to the soil contamination with BPA.

Phytoremediation of soil contaminated with nickel, cadmium and cobalt

This pot experiment analyzed the use of Brassica napus, Elymus elongatus and Zea mays in the removal of Cd²⁺ Co²⁺ and Ni²⁺ from the soil. The utility of the plants under study for phytoremediation was analyzed based on the biomass of the aboveground parts and roots and the accumulation of metals, bioaccumulation, bioconcentration and translocation capability in the above-ground parts and roots. The effect of heavy metals on the soil enzyme activity and soil physicochemical properties was also determined. Among the species under study, only E. elongatus was found to be suitable for Cd²⁺ phytoextraction, whereas E. elongatus and Z. mays proved to be suitable for phytostabilisation of Cd²⁺ and Co²⁺ because the criterion of the accumulation of metals in the roots at a sufficient level was fulfilled. The index of bioaccumulation in roots was greater than one. Both plant species met the second condition which determined the utility for phytostabilisation, as since the transport of Cd²⁺ Co²⁺ and Ni²⁺ from the roots to the above-ground parts was limited.

Soil Microbiome Response to Contamination with Bisphenol A, Bisphenol F and Bisphenol S

The choice of the study objective was affected by numerous controversies and concerns around bisphenol F (BPF) and bisphenol S (BPS)—analogues of bisphenol A (BPA). The study focused on the determination and comparison of the scale of the BPA, BPF, and BPS impact on the soil microbiome and its enzymatic activity. The following parameters were determined in soil uncontaminated and contaminated with BPA, BPF, and BPS: the count of eleven groups of microorganisms, colony development (CD) index, microorganism ecophysiological diversity (EP) index, genetic diversity of bacteria and activity of dehydrogenases (Deh), urease (Ure), catalase (Cat), acid phosphatase (Pac), alkaline phosphatase (Pal), arylsulphatase (Aryl) and β-glucosidase (Glu). Bisphenols A, S and F significantly disrupted the soil homeostasis. BPF is regarded as the most toxic, followed by BPS and BPA. BPF and BPS reduced the abundance of Proteobacteria and Acidobacteria and increased that of Actinobacteria. Unique types of bacteria were identified as well as the characteristics of each bisphenol: Lysobacter, Steroidobacter, Variovorax, Mycoplana, for BPA, Caldilinea, Arthrobacter, Cellulosimicrobium and Promicromonospora for BPF and Dactylosporangium Geodermatophilus, Sphingopyxis for BPS. Considering the strength of a negative impact of bisphenols on the soil biochemical activity, they can be arranged as follows: BPS > BPF > BPA. Urease and arylsulphatase proved to be the most susceptible and dehydrogenases the least susceptible to bisphenols pressure, regardless of the study duration.