Effects of microplastics on microbial community dynamics in sediments from the Volturno River ecosystem, Italy.

In this study, the sources, abundance, and ecological implications of microplastic (MP) pollution in Volturno, one of the main rivers in southern Italy, were explored by investigating the MP concentration levels in sediments collected along the watercourse. The samples were sieved through 5- and 2-mm sieves and treated with selective organic solvents. The polymer classes polystyrene (PS), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polycarbonate (PC), nylon 6 (PA6), and nylon 6,6 (PA66) were quantified using pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) and high-performance liquid chromatography (HPLC). Furthermore, a 16S rRNA metagenomic analysis was performed using next-generation sequencing in Ion Torrent™ to explore the bacterial taxonomy and ecological dynamics of sediment samples. The MPs were detected in all samples collected from the study area. PP and PET were the most abundant and frequently detected polymer types in the analysed samples. The total MP concentration ranged from 1.05 to 14.55 ppm (parts per million), identifying two distinct data populations: high- and low-MP-contaminated sediments. According to the Polymer Hazard Index (PHI), MP pollution was categorised as hazard levels III and IV (corresponding to the danger category). Metagenomic data revealed that the presence of MPs significantly affected the abundance of bacterial taxa; Flavobacteraceae and Nocardiaceae, which are known to degrade polymeric substances, were present in high-MP-contaminated sediments. This study provides new insights into the ecological relevance of MP pollution and suggests that microorganisms may serve as biomarkers of MP pollution.

Multi-omic characterisation as a tool to improve knowledge, valorisation and conservation of wild fruit genetic resources: the case of Arbutus unedo L.

The valorisation and conservation of plant genetic resources (PGRs) and wild fruit PGRs are critical to ensure the maintenance of genetic and cultural heritage and to promote new perspectives on resource use. New strategies to characterize PGRs are needed, and the omics approach can provide information that is still largely unknown. The Strawberry tree (Arbutus unedo L.) is an underutilized, drought and fire-resistant species distributed in the Mediterranean area and its berries have large ethnobotanical use. Although their phenolic profile and antioxidant capacity are known, they are not well characterised, particularly from a proteomic perspective. The aim of this work is the characterisation of two ecotypes of A. unedo (Campania and Sicily) from a molecular viewpoint to valorise and encourage the preservation of this wild fruit. Samples were collected from two different geographical areas to assess whether different geographical conditions could influence the characteristics of leaves and fruits at the three stages of ripening (green, veraison, red). Proteomic analysis identified 904 proteins, of which 122 showed significance along the ripening. Some of these differentially abundant proteins, such as chalcone synthase, show a marked increase during ripening. The protein functional classes with the highest representation are involved in protein and amino acid metabolism, glycolysis and in secondary metabolism. From a proteomic perspective, there are no differences between the fruits from the two regions compared by the ripening stage. However, the pedoclimatic metabolic imprinting allowed the observation of good diversity in the metabolomic profiles between the two ecotypes, especially for anthocyanins, 4 times more abundant in the Sicilian veraisoned fruit than in the Campania one, and catechins, with double the abundance in the Campania ecotype compared to the Sicilian ecotype in the green phase, but more abundant (3x) in the Sicilian veraisoned fruit. Phenolic compounds show a 20% greater abundance in the Campania green arbutus fruit than in the Sicilian one, values that then equalise as ripening progresses. Multi-omic characterisation enhanced the knowledge on a wild fruit plant species which shows specific adaptations and responses to the environment to be considered when addressing the issue of local agrobiodiversity.

Quercus ilex Phyllosphere Microbiome Environmental-Driven Structure and Composition Shifts in a Mediterranean Contex.

The intra- and interdomain phyllosphere microbiome features of Quercus ilex L. in a Mediterranean context is reported. We hypothesized that the main driver of the phyllosphere microbiome might be the season and that atmospheric pollutants might have a co-effect. Hence, we investigated the composition of epiphytic bacteria and fungi of leaves sampled in urban and natural areas (in Southern Italy) in summer and winter, using microscopy and metagenomic analysis. To assess possible co-effects on the composition of the phyllosphere microbiome, concentrations of particulate matter and polycyclic aromatic hydrocarbons (PAHs) were determined from sampled leaves. We found that environmental factors had a significative influence on the phyllosphere biodiversity, altering the taxa relative abundances. Ascomycota and Firmicutes were higher in summer and in urban areas, whereas a significant increase in Proteobacteria was observed in the winter season, with higher abundance in natural areas. Network analysis suggested that OTUs belonging to Acidobacteria, Cytophagia, unkn. Firmicutes(p), Actinobacteria are keystone of the Q. ilex phyllosphere microbiome. In addition, 83 genes coding for 5 enzymes involved in PAH degradation pathways were identified. Given that the phyllosphere microbiome can be considered an extension of the ecosystem services offered by trees, our results can be exploited in the framework of Next-Generation Biomonitoring.

Holistic tool for ecosystem services and disservices assessment in the urban forests of the Real Bosco di Capodimonte, Naples.

A tool for urban forest Ecosystem services (ES) and disservices (ED) assessment has been developed to visualize (i) overall ES and ED value, (ii) ES-ED trade-off and (iii) explore principal influences in ES and ED provision. The Real Bosco di Capodimonte (RBC) (Naples, Southern Italy) has been chosen as a case study. ES and ED linked to urban forest plant cover were: biodiversity, carbon storage, gross and net carbon sequestration, lessen runoff, oxygen production, air pollution removal, UV effects reduction, pollen-related allergenicity risk, and volatile organic compounds (VOCs) emissions. A phytosociological survey was conducted and biodiversity value was evaluated. ES and ED were assessed by i-Tree Eco model and Index of Urban Green Zones Allergenicity (IUGZA). Results showed that 441 different plant species occur in the RBC and the most represented genera are Quercus and Trifolium, while the largest family was Asteraceae. Carbon storage and pollution removal were highest in natural forest, while remaining ES were greater in managed forest areas. Highest value for VOCs emission and allergenicity were assigned to managed and natural forest, respectively. Managed forest scored the highest ES-ED value, while managed grassland scored the lowest. Results highlighted the greater influence of plant cover structure in overall ES and ED provision levels, and management influence considering the same type of plant cover. The model could be a valuable tool for ES and ED effective management generally applicable in urban forests.

An Endemic Plant of the Mediterranean Area: Phytochemical Characterization of Strawberry Tree (Arbutus unedo L.) Fruits Extracts at Different Ripening Stages.

This work focused on the extraction, quantification, and characterization of bioactive compounds of Arbutus unedo L. fruits, comparing the results obtained from the different ripening states. Extractions were performed by different methods (such as maceration extraction and ultrasonic extraction) and food grade solvents (aqueous and hydroalcoholic solvents) in each of the all ripening states (four states considered, associated with four different colors, i.e., green, yellow, orange, and red). The presence of (poly)phenols was quantified and characterized, and scavenging activity was determined by the Folin-Ciocâlteu reagent and the DPPH method, respectively. The content of bioactive compounds was characterized by LC-MS/MS, such as multiple reaction monitoring (MRM) mass spectrometry. The results showed that ultrasound-assisted extraction (UAE) performed better than maceration extraction; ethanol-water mixture extracts showed a more positive effect than the use of aqueous extracts regarding the content of total phenolic compounds. Overall, the total phenolic compounds in the EtOH:H2O mixture at a ratio of 7:3 (v:v) were higher than that of the other solvents for both extraction methods. Some bioactive molecules were characterized for the first time in the extracts of A. unedo. The chemical profile of the strawberry tree extracts depended on the degree of fruit ripeness. The results suggest that A. unedo fruits may be of great interest for food and nutraceutical applications.

Influence of sediment texture on HDPE microplastics recovery by density separation.

Microplastics (MPs) are an emerging environmental pollutant, threatening marine and terrestrial ecosystems. Because of their properties and their widely varying size (5mm-0.1 µm), it is still difficult to define a valid and efficient method for extracting MPs from solid matrices. Among the several methods proposed, density separation is the most practical and cost-effective one. Progress is still ongoing towards a deeper understanding of the advantages and limitations related to the application of density separation for MPs extraction, the recovery yields and the factors that may influence it. In this context, we introduce the following work, which provides an early-stage insight into how the sediment texture may influence the efficiency of this extraction method, and how parameters, such as sedimentation time and extraction cycles, can be modified to always achieve the best recovery. Our focus has been directed on evaluating the extraction efficiency of HDPE MPs by density separation using NaCl, from three types of sediment: sandy (SS), sandy loam (SLS) and sandy-clay loam (SCLS). We investigated the impact of sedimentation time (1, 6, 12, 24 h) and extraction cycles (3 cycles for each sedimentation time) on MPs recovery. Finally, we determined the minimum amount of MPs (MPs g/g sediment) below which it is not possible to quantify MPs with the method used. The results have shown that the recovery efficiency of MPs from sediment is structure dependent. The highest recoveries are reached after a settling time of 1 and 6 h. Furthermore, for samples with minimum clay content (SS), only one extraction cycle is needed, whereas two extraction cycles are required for SLS and SCLS. The outcomes about the detection limit (LOD) of the method, showed the existence of an interaction MPs-clay/sediment, which allowed us to understand how far this extraction method is suitable in field, thus defining the minimum grade of MPs pollution (MPs g/g sediment) below which this method is no longer capable to extract MPs from contaminated samples.

Biotechnological Combination for Co-contaminated Soil Remediation: Focus on Tripartite "Meta-Enzymatic" Activity.

Soil pollution is a pressing problem requiring solutions that can be applied without large-scale side effects directly in the field. Phytoremediation is an effective strategy combining plant and root-associated microbiome to immobilize, degrade, and adsorb pollutants from the soil. To improve phytoremediation, it is necessary to think of plants, fungi, and bacteria not as individual entities, but as a meta-organism that reacts organically, synergistically, and cooperatively to environmental stimuli. Analyzing the tripartite enzymatic activity in the rhizosphere is necessary to understand the mechanisms underlying plant-microorganism communication under abiotic stress (such as soil pollution). In this work, the potential of a microbial consortium along with a plant already known for its phytoremediation capabilities, Schedonorus arundinaceus (Scheb.) Dumort., was validated in a mesocosm experiment with pluricontaminated soil (heavy metals, PAHs, and PCBs). Chemical analyses of the soil at the beginning and end of the experiment confirmed the reduction of the main pollutants. The microscopic observation and chemical analyses confirmed the greater root colonization and pollutant removal following the microbial treatment. To obtain a taxonomic and functional picture, tripartite (plant, fungi, and bacteria) enzyme activity was assessed using a metatranscriptomic approach. Total RNA was extracted from a sample of rhizosphere sampled considering 2 centimeters of root and soil attached. From the total reads obtained, mRNAs were filtered, and analysis focused on reads identified as proteins with enzymatic activity. The differential analysis of transcripts identified as enzymes showed that a general increase in potential enzyme activity was observed in the rhizosphere after our biotechnological treatment. Also from a taxonomic perspective, an increase in the activity of some Phyla, such as Actinobacteria and Basidiomycota, was found in the treated sample compared to the control. An increased abundance of enzymes involved in rhizospheric activities and pollutant removal (such as dehydrogenase, urease, and laccase) was found in the treated sample compared to the control at the end of the experiment. Several enzymes expressed by the plant confirmed the increase in metabolic activity and architectural rearrangement of the root following the enhancement of the rhizospheric biome. The study provides new outcomes useful in rhizosphere engineering advancement.

Particulate matter and polycyclic aromatic hydrocarbon uptake in relation to leaf surface functional traits in Mediterranean evergreens: Potentials for air phytoremediation.

We explored relationships between particulate matter (PM) and polycyclic aromatic hydrocarbon (PAHs) leaf concentrations, uptake rates and leaf surface functional traits in four Mediterranean evergreen trees (Chamaerops humilis, Citrus × aurantium, Magnolia grandiflora, and Quercus ilex) during a dry month. Pollutant leaf concentration at different dates and uptake rate were correlated. We quantified PM by gravimetric analysis, PAHs were extracted from intact and dewaxed leaves and analyzed by GC-MS, and cuticle thickness, number and surface of stomata (Ns and SS) and trichomes (Nt and St) were determined by optical microscopy. Infrared spectroscopy was used to investigate the leaves surfaces composition and assess esterification index (E). Studied species were characterized by unique combinations of functional traits and pollutant uptake capacities. PM10 uptake scaled positively with SS, St and upper cuticle thickness (Tc,u) across species. PM2.5 uptake scaled positively with Tc,u, and thicker cuticles were also associated with greater shares of uptake of hydrophobic PM fractions. Uptakes of different fractions of PAH were generally weakly related to different leaf functional traits, except for some correlations with E and SS. We conclude that both plant surface morphological and chemical leaf traits influence PM and PAH retention, unveiling their potential role in air phytoremediation.

Exploring an enhanced rhizospheric phenomenon for pluricontaminated soil remediation: Insights from tripartite metatranscriptome analyses.

Phytoremediation involving the use of microorganisms with tolerant plant species represents a new frontier for on-site remediation of pluricontaminated soils. In this study, the effectiveness of a biotechnological strategy, involving the use of Festuca arundinacea and a pool of microorganisms, was assessed by a mesocosm experiment and an in-depth rhizospheric metatranscriptomic analysis. The chemical profile of mesocosm soil at the end of the experiment (240 days) showed that the decrease of trace elements such as Cd, Hg, Pb, Sn, Tl, V and Zn in the soil was enhanced by our biological combination. Additionally, also the organic pollutants (PAHs and PCBs) were strongly reduced up to 40.5%. About two million transcripts were identified and used for taxonomic and functional profiling. Transcripts read counts, tripartite among plant, bacteria and fungi were identified and quantified to provide an overview of the complex soil community composition. We observed that Actinobacteria and fungi abundance might be involved in remediation success. Functional analyses showed that Trehalose Biosynthesis and the antioxidant activity might have played a key-role in metaorganism effective interactions. The biotechnological approach remodeled the transcriptional profile toward organic pollutant degradation and heavy metal stress response.

Overcome the limits of multi-contaminated industrial soils bioremediation: Insights from a multi-disciplinary study.

Phytoremediation can be a promising and sustainable strategy to recovery Potentially Toxic Elements (PTEs) contaminated soils. However, at the field level, this tool can be limited by many issues. Herein, we combined native plant species with different cover type (mono and poly culture) in an in-field mesocosm experiment for the remediation of multi-contaminated soils from Bagnoli brownfield site (Southern Italy). We preliminary gain insights about the physical, chemical and biological features of the soils and subsequently induced a potential variation in the soil microbiome. We found that polyculture better respond both in terms of pollutant phytostabilization efficiency and from a stress tolerance perspective. Among plant species, Festuca achieved the best performance due to the overexpression of metal transporters able in both PTEs influx and sequestration from the cytoplasm. We achieved a site-specific bio-factory, which represents a strategy for the sustainable and relatively fast recovery of large contaminated areas.

The remediation potential for PAHs of Verbascum sinuatum L. combined with an enhanced rhizosphere landscape: A full-scale mesocosm experiment.

A full-scale mesocosm study was conducted to depict how integrated biological systems interact to adapt to contaminant stress and improve remediation of polycyclic aromatic hydrocarbons (PAHs)contaminated soils. The combination of Verbascum sinuatum L. and microbial consortium (fungi and bacteria) was employed along with three differently contaminated soils. After 240 days the highest PAHs removal (up to 68 %) and 6-rings compounds decrease was found in soil with lower pollution and cation exchange capacity. V. sinuatum showed a significant adaptability over time in terms of redox biology. Soil enzyme activities and microscopic evidences proved a rising plant-microorganisms association and a successful mycorrhization, arising from the inoculation of our consortia. In addition, an enhanced richness of PAHs degrading genes was achieved. Microbial co-metabolism, helped by the establishment of complex relationships with hosting plant, demonstrated to be suitable for the degradation of high molecular weight PAHs and represents a biotechnology with great prospects.