Search

The occurrence of microplastics (MPs) and nanoplastics (NPs) in soils potentially induce morphological, physiological, and biochemical alterations in plants. The present study investigated the effects of MPs/NPs on lettuce (Lactuca sativa L. var. capitata) plants by focusing on (i) four different particle sizes of polyethylene micro- and nanoplastics, at (ii) four concentrations. Photosynthetic activity, morphological changes in plants, and metabolomic shifts in roots and leaves were investigated. Our findings revealed that particle size plays a pivotal role in influencing various growth traits of lettuce (biomass, color segmentation, greening index, leaf area, and photosynthetic activity), physiological parameters (including maximum quantum yield - Fv/Fmmax, or quantum yield in the steady-state Fv/FmLss, NPQLss, RfdLss, FtLss, FqLss), and metabolomic signatures. Smaller plastic sizes demonstrated a dose-dependent impact on aboveground plant structures, resulting in an overall elicitation of biosynthetic processes. Conversely, larger plastic size had a major impact on root metabolomics, leading to a negative modulation of biosynthetic processes. Specifically, the biosynthesis of secondary metabolites, phytohormone crosstalk, and the metabolism of lipids and fatty acids were among the most affected processes. In addition, nitrogen-containing compounds accumulated following plastic treatments. Our results highlighted a tight correlation between the qPCR analysis of genes associated with the soil nitrogen cycle (such as NifH, NirK, and NosZ), available nitrogen pools in soil (including NO3- and NH4), N-containing metabolites and morpho-physiological parameters of lettuce plants subjected to MPs/NPs. These findings underscore the intricate relationship between specific plastic contaminations, nitrogen dynamics, and plant performance.

The use of microbial biostimulants in agriculture is recognized as a sustainable approach to promoting crop productivity and quality due to improved nutrient uptake, enhanced stress tolerance, and improved ability to cope with non-optimal environments. The present paper aimed to comparatively investigate the effect of seven different commercial mycorrhizal-based treatments in terms of yield, phytochemical components, and technological traits of Malvasia di Candia Aromatica grape (Vitis vinifera L.) plants. Metabolomic analysis and photosynthetic performance were first investigated in leaves to point out biochemical differences related to plant growth. Higher photosynthetic efficiency and better PSII functioning were found in biostimulant-treated vines, reflecting an overall decrease in photoinhibition compared to untreated plants. Untargeted metabolomics followed by multivariate statistics highlighted a robust reprogramming of primary (lipids) and secondary (alkaloids and terpenoids) metabolites in treated plants. The analysis of berry yield and chemical components exhibited significant differences depending on the biostimulant product. Generally, berries obtained from treated plants displayed improved contents of polyphenols and sugars, while yield remained unchanged. These results elucidated the significant role of microbial biostimulants in determining the quality of grape berries and eliciting biochemical changes in vines.

Plant growth-promoting rhizobacteria (PGPR) with antagonistic activity toward plant pathogenic fungi are valuable candidates for the development of novel plant protection products based on biocontrol activity. The very first step in the formulation of such products is to screen the potential effectiveness of the selected microorganism(s). In this study, non-pathogenic rhizobacteria were isolated from the rhizosphere of tomato plants and evaluated for their biocontrol activity against three species of mycotoxin-producing Alternaria. The assessment of their biocontrol potential involved investigating both fungal biomass and Alternaria toxin reduction. A ranking system developed allowed for the identification of the 12 best-performing strains among the initial 85 isolates. Several rhizobacteria showed a significant reduction in fungal biomass (up to 76%) and/or mycotoxin production (up to 99.7%). Moreover, the same isolates also demonstrated plant growth-promoting (PGP) traits such as siderophore or IAA production, inorganic phosphate solubilization, and nitrogen fixation, confirming the multifaceted properties of PGPRs. Bacillus species, particularly B. amyloliquefaciens and two strains of B. subtilis, showed the highest efficacy in reducing fungal biomass and were also effective in lowering mycotoxin production. Isolates such as Enterobacter ludwigii, Enterobacter asburiae, Serratia nematodiphila, Pantoea agglomerans, and Kosakonia cowanii showed moderate efficacy. Results suggest that by leveraging the diverse capabilities of different microbial strains, a consortium-based approach would provide a broader spectrum of effectiveness, thereby signaling a more encouraging resolution for sustainable agriculture and addressing the multifaceted nature of crop-related biotic challenges.

The application of microbial biostimulants to plants has revealed positive effects related to nutrients uptake, stress tolerance, root development and phenological growth. However, little information is available exploiting the potential synergistic biostimulant action of microbes on the functional quality of the yields. The current research elucidated the effect of single or coupled action of biostimulants, associated with either optimal or reduced nitrogen application, on the functional quality of tomato fruits. Chemical assays and untargeted metabolomics were applied to investigate Rhizoglomus irregulare and Funneliformis mosseae administration (both being arbuscular mycorrhiza, AMF), under optimal or low N input conditions, alone or coupled to Trichoderma atroviride application. The coupling of AMF and Trichoderma fungal inoculations resulted in a synergistic biostimulant effect on tomato fruits under sub-optimal fertility, revealing improved concentrations of carotenoid compounds-B-carotene (0.647 +/- 0.243 mg/100 g), Z-carotene (0.021 +/- 0.021 mg/100 g), 13-z-lycopene (0.145 +/- 0.052 mg/100 g) and all-trans-lycopene (12.586 +/- 1.511 mg/100 g), and increased values for total phenolic content (12.9 +/- 2.9 mgGAE/g), total antioxidant activity (phosphomolybdenum, 0.9 +/- 0.2 mmolTE/g), radical scavenging activity (DPPH, 3.4 +/- 3.7 mgTE/g), reducing power (FRAP, 23.6 +/- 6.3 mgTE/g and CUPRAC, 37.4 +/- 7.6 mg TE/g), and enzyme inhibitory activity (AChE, 2.4 +/- 0.1 mg GALAE/g), when compared to control. However, evidence of carotenoid and bioactive compounds were exclusively observed under the sub-optimal fertility and no significant differences could be observed between the biostimulant treatment and control under optimal fertility.

Metallic nanoparticles (MNPs) are becoming widespread environmental contaminants. They are currently added to several food preparations and cause a fast-growing concern for human health. The present work aims to assess the impact of zinc oxide (ZnO), titanium dioxide (TiO2), and silver (Ag) nanoparticles (NPs) on the human gut metabolome and microbiome. Water samples spiked with two different concentrations of each MNPs were subjected to in-vitro gastrointestinal digestion and in-vitro large intestine fermentation. The effects of the treatments were determined through 16 S amplicon sequencing and untargeted metabolomics. Multi-omics data integration was then applied to correlate the two datasets. MNPs treatments modulated the microbial genera Bifidobacterium, Sutterella, Escherichia and Bacteroides. The treatments, especially the lower concentrations of Ag and ZnO, caused modulation of indole derivatives, peptides, and metabolites related to protein metabolism in the large intestine. Notably, these metabolites are implicated in ulcerative colitis and inflammatory bowel disease. TiO2 NPs treatment in all concentrations increased E.coli relative abundance and decreased the abundance of B. longum. Moreover, for TiO2, an enrichment in proinflammatory lipid mediators of arachidonic acid metabo-lites, such as prostaglandin E2 and leukotrienes B4, was detected. For all metals except TiO2, low NP concen-trations promoted differentiated profiles, thus suggesting that MNPs aggregation can limit adverse effects on living cells.

This study aims to provide information on the behaviour and biopersistence rate (BP) of metallic nanoparticles (Ag-NPs, TiO2-NPs, ZnO-NPs) naturally occurring in canned seafood and subjected to static in vitro digestion. Single particle ICP-MS analysis was performed to determine NPs distribution and concentrations in oral, gastric, and intestinal digests. Depending on the conditions of the digestive phase and the sample matrix, the phenomena of agglomeration and dispersion were highlighted and confirmed by Dynamic Light Scattering (DLS) technique. In standard suspensions, Ag-NPs had lower biopersistence (BP) than ZnO and TiO2-NPs (BP 34%, 89% and >100%, respectively). Among Ag-NPs and TiO2-NPs naturally present in the food matrix, those in canned tuna were more degradable than those in canned clam (BP Ag-NPs 36% vs. > 100%; BP TiO2-NPs 96% vs. > 100%), while BP ZnO-NPs showed high biopersistence in both seafood matrix (>100%). The biopersistence rates were higher than the recommended limit set by European Food Safety Authority (EFSA) (12%), referred to nanotechnologies to be applied in the food and feed chain, thus the investigated naturally occurring NPs cannot be considered readily degradable.

Combining no-till and cover crops (NT + CC) as an alternative to conventional tillage (CT) is generating interest to build-up farming systems’ resilience while promoting climate change adaptation in agriculture. Our field study aimed to assess the impact of long-term NT + CC management and short-term water stress on soil microbial communities, enzymatic activities, and the distribution of C and N within soil aggregates. High-throughput sequencing (HTS) revealed the positive impact of NT + CC on microbial biodiversity, especially under water stress conditions, with the presence of important rhizobacteria (e.g., Bradyrhizobium spp.). An alteration index based on soil enzymes confirmed soil depletion under CT. C and N pools within aggregates showed an enrichment under NT + CC mostly due to C and N-rich large macroaggregates (LM), accounting for 44% and 33% of the total soil C and N. Within LM, C and N pools were associated to microaggregates within macroaggregates (mM), which are beneficial for long-term C and N stabilization in soils. Water stress had detrimental effects on aggregate formation and limited C and N inclusion within aggregates. The microbiological and physicochemical parameters correlation supported the hypothesis that long-term NT + CC is a promising alternative to CT, due to the contribution to soil C and N stabilization while enhancing the biodiversity and enzymes.

Introducing smart and sustainable tools for climate change adaptation and mitigation is a major need to support agriculture’s productivity potential. We assessed the effects of the processed gypsum seed dressing SOP® COCUS MAIZE+ (SCM), combined with a gradient of N fertilization rates (i.e., 0%, 70% equal to 160 kg N ha−1, and 100% equal to 230 kg N ha−1) in maize (Zea mays L.), on: (i) grain yield, (ii) root length density (RLD) and diameter class length (DCL), (iii) biodiversity of soil bacteria and fungi, and (iv) Greenhouse Gases (GHGs, i.e., N2O, CO2, and CH4) emission. Grain yield increased with SCM by 1 Mg ha−1 (+8%). The same occurred for overall RLD (+12%) and DCL of very fine, fine, and medium root classes. At anthesis, soil microbial biodiversity was not affected by treatments, suggesting earlier plant-rhizosphere interactions. Soil GHGs showed that (i) the main driver of N losses as N2O is the N-fertilization level, and (ii) decreasing N-fertilization in maize from 100% to 70% decreased N2O emissions by 509 mg N-N2O m−2 y−1. Since maize grain yield under SCM with 70% N-fertilization was similar to that under Control with 100% N-fertilization, we concluded that under our experimental conditions SCM may be used for reducing N input (−30%) and N2O emissions (−23%), while contemporarily maintaining maize yield. Hence, SCM can be considered an available tool to improve agriculture’s alignment to the United Nation Sustainable Development Goals (UN SDGs) and to comply with Europe’s Farm to Fork strategy for reducing N-fertilizer inputs.

New agronomical policies aim to achieve greener agricultural systems, sustainable fertilizers and fungicides, a reduction in Greenhouse gases (GHG), and an increase in circular economic models. In this context, new solutions are needed for the market, but it is necessary to carefully assess both their efficacy and their ecological impact. Previously, we reported the biostimulatory activity on soil microbiome for a side-product from Lactic Acid Bacteria (LABs) fermentation: a concentrated post-centrifugation eluate. In the present study, we investigated whether this solution could partially substitute mineral N (N70% + N30% from eluate) in a fertigation (N100% vs. N70%) regime for tomato and lettuce under greenhouse conditions. The impact of the application was investigated through plant physiological parameters (number and weight of ripened fruits, shoots, and roots biomass) and biodiversity of the rhizosphere microbial composition of bacteria and fungi (High-Throughput Sequencing-HTS). The eluate (i) enhanced the plant canopy in lettuce; (ii) increased the shoot/root biomass ratio in both tomato and lettuce; and (iii) increased the harvest and delayed fruit ripening in tomato. Moreover, we found a strong correlation between the eluate and the enrichment for OTUs of plant-growth-promoting microbes (PGPMs) such as Sphingomonas sediminicola, Knoellia subterranean, and Funneliformis mosseae. These findings suggest that integrating the eluate was beneficial for the plant growth, performance, and yield in both tomato and lettuce, and additionally, it enriched specialized functional microbial communities in the rhizosphere. Further studies will investigate the underlying mechanisms regulating the selective activity of the eluate toward PGPMs and its biostimulatory activity towards target crops.

A 3-m thick sediment sequence, found in a limestone mine located in the south of Italy at a depth of ca. 25–30 m from the current ground level, was investigated. Samples from 5 layers were analysed by X-ray diffraction, elemental analysis, Inductively Coupled Plasma Mass Spectrometry and micromorphology. Microbial DNA was analysed by 16S rRNA gene metabarcoding. The main mineral compounds found in the 5 layers were calcite (70–80%) and clay minerals in layers #1 and #5, goethite (75%) and hematite in layer #2, manganese (66%) and iron oxides in layer #3, and almost exclusively goethite in layer #4. Micromorphology data allowed to shed light in understanding whether these sediments formed by subsequent weathering of carbonates and silicates or by migration of soil sediments from the surface, or also by the accumulation of shallow marine sediments occurring between the middle Pliocene and the lower Pleistocene, when the extreme western sector of this area underwent strong subsidence. From the microbiological point of view, upon the 16S rRNA gene analysis, these 5 layers appear to cluster in three groups. Overall, such a distribution suggests that, both in the top (#1) and in bottom layers (#4 and #5), different communities would have undergone in situ reproduction and colonization exploiting metabolically the substrate, whereas the two mid layers would have received bacterial convection by passive transport of percolating waters. At the same time, micromorphological data show that each layer preserved its distinct features to be related to the environmental condition at the time of deposition. The chemical, mineralogical and micromorphological features of the layers and the known physiology of the microbial taxa thereby encountered highlight the possible role of the latter in elucidating the occurrence of certain mineral species as well as the biogeochemistry of elements like Mn and Fe in sediment layers.

The semi-arid Chaco ecoregion has been heavily affected by the conversion of pastures to cropland. Our knowledge about the impact of land use change on soil microbial community diversity and functions in this region is limited. Here, we assessed the impact of different land uses and management practices (i.e.: ungrazed pasture, grazed pasture and cropping systems under zero and conventional tillage) on soil bacterial communities structure and functions, as well as their relations with edaphic properties. The taxonomic diversity of bacterial communities was mainly dominated by the phyla Firmicutes, Proteobacteria and Actinobacteria. Alpha diversity was the highest in grazed pasture (OTU richness, Chao and Shannon), and it was the lowest in ungrazed pasture. Soil organic carbon, nitrogen and pH were the main determining variables of bacterial community composition and diversity. Predicted functional profiles revealed the gene abundances involved in amino acid, energy and carbohydrate metabolisms; and in categories related to nucleotide transport, metabolism, translation ribosomal structure, and biogenesis. These abundances were higher in agricultural than pastoral systems. Our results suggest that changes in soil physicochemical properties (i.e. SOC, TN and pH) associated with soil management practices cause shifts in the composition of soil bacterial communities and their metabolic functions in farming systems of the semi-arid Chaco region.

Plastics fragmentation into smaller debris, namely, micro- and nano-plastics (MPs and NPs), is a matter of global concern because of their wide distribution in terrestrial and marine environments. The latest research has focused mainly on aquatic ecosystems, and fragmentation of bioplastics into micro- and nano-particles (MBPs and NBPs) is not considered. The distribution, concentration, fate and major source of MPs, NPS, MBPs and NBPs in agroecosystems still need to be understood. The use of composts and sewage sludge from the organic fraction of municipal solid waste (OFMSW) treatment plants as soil amendments is likely to represent a major input of these debris. The present review provides insights into the current evidence of pollution from micro- and nano-particles of both fossil- and bio-origin in the OFMSW treatment, and aims at evaluating if the recycling of organic waste and its application as a soil fertilizer outweigh the risk of pollution in terrestrial environments. Huge unpredictability exists due to the limited numbers of data on their quantification in each source of possible solution. Indeed, the major hurdles arise from the difficult to quantify the micro-, especially the nano-, particles and subsequently assess the concentrations in the environments, as well as bioaccumulation risks, and toxic effects on organisms. Graphical Abstract: [Figure not available: see fulltext.]

While bioplastics are gaining wide interest in replacing conventional plastics, it is necessary to understand whether the treatment of the organic fraction of municipal solid waste (OFMSW) as an end-of-life option is compatible with their biodegradation and their possible role in shaping the microbial communities involved in the processes. In the present work, we assessed the microbiological impact of rigid polylactic acid (PLA) and starch-based bioplastics (SBB) spoons on the thermophilic anaerobic digestion and the aerobic composting of OFMSW under real plant conditions. In order to thoroughly evaluate the effect of PLA and SBB on the bacterial, archaeal, and fungal communities during the process, high-throughput sequencing (HTS) technology was carried out. The results suggest that bioplastics shape the communities’ structure, especially in the aerobic phase. Distinctive bacterial and fungal sequences were found for SBB compared to the positive control, which showed a more limited diversity. Mucor racemosus was especially abundant in composts from bioplastics’ treatment, whereas Penicillium roqueforti was found only in compost from PLA and Thermomyces lanuginosus in that from SBB. This work shed a light on the microbial communities involved in the OFMSW treatment with and without the presence of bioplastics, using a new approach to evaluate this end-of-life option.

Nowadays, agriculture is facing the great challenge of climate change which puts the productivity of the crops in peril due to unpredictable rain patterns and water shortages, especially in the developing world. Besides productivity, nutritional values of the yields of these crops may also be affected, especially under low mechanization and the low water availability conditions of the developing world. Conservation agriculture (CA) is a topic of emerging interest due to the provision of adequate yields and reduced environmental impact, such as greenhouse gas emissions, by being based on three main principles: minimum soil disturbance (reduced or no tillage), cover crop maintenance, and crop rotation. The aim of this study was to assess the impact of CA management on the growth performance and the nutritional profile of cowpea (Vigna unguiculata L. Walp), a pulse of African origin, commonly known as black eye bean under field conditions. A field experiment was designed to assess the effect of conventional tillage (CT) and no-tillage (NT) combined with the usage of a set of cover crops, coupled to normal and deficient water regimes. Cowpea was revealed to be able to grow and yield comparably at each level of the treatment tested, with a better ability to face water exhaustion under CA management. After a faster initial growth phase in CT plots, the level of adaptability of this legume to NT was such that growth performances improved significantly with respect to CT plots. The flowering rate was higher and earlier in CT conditions, while in NT it was slower but longer-lasting. The leafy photosynthetic rate and the nutritional profile of beans were slightly influenced by tillage management: only total starch content was negatively affected in NT and watered plots while proteins and aminoacids did not show any significant variation. Furthermore, significantly higher carbon and nitrogen concentration occurred in NT soils especially at the topmost (0–5 cm) soil horizon. Th

Nowadays, agriculture is facing the great challenge of climate change which puts the productivity of the crops in peril due to unpredictable rain patterns and water shortages, especially in the developing world. Besides productivity, nutritional values of the yields of these crops may also be affected, especially under low mechanization and the low water availability conditions of the developing world. Conservation agriculture (CA) is a topic of emerging interest due to the provision of adequate yields and reduced environmental impact, such as greenhouse gas emissions, by being based on three main principles: minimum soil disturbance (reduced or no tillage), cover crop maintenance, and crop rotation. The aim of this study was to assess the impact of CA management on the growth performance and the nutritional profile of cowpea (Vigna unguiculata L. Walp), a pulse of African origin, commonly known as black eye bean under field conditions. A field experiment was designed to assess the effect of conventional tillage (CT) and no-tillage (NT) combined with the usage of a set of cover crops, coupled to normal and deficient water regimes. Cowpea was revealed to be able to grow and yield comparably at each level of the treatment tested, with a better ability to face water exhaustion under CA management. After a faster initial growth phase in CT plots, the level of adaptability of this legume to NT was such that growth performances improved significantly with respect to CT plots. The flowering rate was higher and earlier in CT conditions, while in NT it was slower but longer-lasting. The leafy photosynthetic rate and the nutritional profile of beans were slightly influenced by tillage management: only total starch content was negatively affected in NT and watered plots while proteins and aminoacids did not show any significant variation. Furthermore, significantly higher carbon and nitrogen concentration occurred in NT soils especially at the topmost (0–5 cm) soil horizon. Th

Apis mellifera is an important provider of ecosystem services, and during flight and foraging behaviour is exposed to environmental pollutants including airborne particulate matter (PM). While exposure to insecticides, antibiotics, and herbicides may compromise bee health through alterations of the gut microbial community, no data are available on the impacts of PM on the bee microbiota. Here we tested the effects of ultrapure Titanium dioxide (TiO2) submicrometric PM (i.e., PM1, less than 1 µm in diameter) on the gut microbiota of adult bees. TiO2 PM1 is widely used as a filler and whitening agent in a range of manufactured objects, and ultrapure TiO2 PM1 is also a common food additive, even if it has been classified by the International Agency for Research on Cancer (IARC) as a possible human carcinogen in Group 2B. Due to its ubiquitous use, honey bees may be severely exposed to TiO2 ingestion through contaminated honey and pollen. Here, we demonstrated that acute and chronic oral administration of ultrapure TiO2 PM1 to adult bees alters the bee microbial community; therefore, airborne PM may represent a further risk factor for the honey bee health, promoting sublethal effects against the gut microbiota.

Combining no-till and cover crops (NT + CC) as an alternative to conventional tillage (CT) is generating interest to build-up farming systems’ resilience while promoting climate change adaptation in agriculture. Our field study aimed to assess the impact of long-term NT + CC management and short-term water stress on soil microbial communities, enzymatic activities, and the distribution of C and N within soil aggregates. High-throughput sequencing (HTS) revealed the positive impact of NT + CC on microbial biodiversity, especially under water stress conditions, with the presence of important rhizobacteria (e.g., Bradyrhizobium spp.). An alteration index based on soil enzymes confirmed soil depletion under CT. C and N pools within aggregates showed an enrichment under NT + CC mostly due to C and N-rich large macroaggregates (LM), accounting for 44% and 33% of the total soil C and N. Within LM, C and N pools were associated to microaggregates within macroaggregates (mM), which are beneficial for long-term C and N stabilization in soils. Water stress had detrimental effects on aggregate formation and limited C and N inclusion within aggregates. The microbiological and physicochemical parameters correlation supported the hypothesis that long-term NT + CC is a promising alternative to CT, due to the contribution to soil C and N stabilization while enhancing the biodiversity and enzymes.

Agrochemicals are commonly used in agriculture to protect crops and ensure yields. Several of them are mobile within the plant and, being perceived as xenobiotics regardless of their protective/curative roles, they induce a reprogramming of secondary metabolism linked to the detoxification processes even in the absence of phenotype symptoms. Moreover, it is well documented that plants are able to shape the microbial population at the rhizosphere and to significantly affect the processes occurring therein thanks to the root exudation of different metabolites. Here we show that plant metabolic response to foliarly-applied pesticides is much broader than what previously thought and includes diverse and compound-specific hidden processes. Among others, stress-related metabolism and phytohormones profile underwent a considerable reorganization. Moreover, a distinctive microbial rearrangement of the rhizosphere was recorded following foliar application of pesticides. Such effects have unavoidably energetic and metabolic costs for the plant paving the way to both positive and negative aspects. The understanding of these effects is crucial for an increasingly sustainable use of pesticides in agriculture.

Environmental DNA is made-up of intracellular (iDNA) and extracellular (eDNA) pools. In soils, eDNA can be present up to 40% and could distort the assessment of living microorganisms. Distribution of microbial community is inconsistent among different size-aggregates, and the persistence and turnover of eDNA are thus uneven. Uneven persistence and distribution of eDNA could lead to heterogeneity in community analysis biases that arise due to eDNA sequences at micro-scale distribution. Here, we investigated the diversity and structure of eDNA and iDNA bacterial communities in bulk soil and different size-aggregates. Significant differences were observed between eDNA and iDNA bacterial diversity and composition. Changes in community composition are more important than the amount of eDNA to assess the biases caused by eDNA in community analysis. Furthermore, variations were also observed in aggregates-levels for eDNA and iDNA community which indicates that colonization pattern of iDNA community and protection of eDNA through absorbance on particle surface within soil-matrix is heterogeneous. Our work provides empirical evidence that eDNA presence could mask the detection of aggregates-level spatial dynamics in soil microbial community and have potential to qualitatively baffle observed live effects of given treatment by adequately muting the actual response dynamics of the soil microbiome.

Despite being not essential to plants, Silicon (Si) has proven to have promoting effects on plants growth, yield, and resistance against biotic and abiotic stressors. The increase of concentration in specific minerals in plant tissues can also improve shelf-life, which, in fruits like strawberries, is also affected by the epiphytic microbial community. The present research was carried out to assess whether Si biofortification of strawberry plants, grown in soilless system, could affect plants yield and post-harvest feature of fruits during the storage period, carried out at three different temperatures (i.e., 1, 4 and 10 °C) for 7 and 14 days. Furthermore, we investigated whether the plant nutritional regime, specifically the Si fertilization, can impact the composition of microbial community. Our results showed that biofortification did not significantly affect fruits firmness, whereas, at the highest Si levels, an increase in titratable acidity was observed. The microbial community analysis highlighted for the first time the presence of probiotic bacteria, as Bacillus breve, which could present interesting technological features as strains adapted to the strawberry fruit-sphere. In addition, with the increasing levels of Si biofortification, the depletion of potentially pathogenic microorganisms, like Escherichia coli and Terrisporobacter glycolicus, was also observed. In conclusion, data here reported highlight for the first time the possible role played by the nutritional regimes of strawberry plants in shaping composition of the fruit epiphytic microbial community.

Plant growth promoting rhizobacteria (PGPR) can display several plant-beneficial properties, including support to plant nutrition, regulation of plant growth, and biocontrol of pests. Mechanisms behind these effects are directly related to the presence and expression of specific genes, and different PGPR strains can be differentiated by the presence of different genes. In this study we reported a comprehensive evaluation of a novel PGPR Klebsiella variicola UC4115 from the field to the lab, and from the lab to the plant. The isolate from tomato field was screened in-vitro for different activities related to plant nutrition and growth regulation as well as for antifungal traits. We performed a functional annotation of genes contributing to plant-beneficial functions previously tested in-vitro. Furthermore, the in-vitro characterization, the whole genome sequencing and annotation of K. variicola UC4115, were compared with the well-known PGPR Azospirillum brasilense strain Sp7. This novel comparative analysis revealed different accumulation of plant-beneficial functions contributing genes, and the presence of different genes that accomplished the same functions. Greenhouse assays on tomato seedlings from BBCH 11–12 to BBCH > 14 were performed under either organic or conventional management. In each of them, three PGPR inoculations (control, K. variicola UC4115, A. brasilense Sp7) were applied at either seed-, root-, and seed plus root level. Results confirmed the PGP potential of K. variicola UC4115; in particular, its high value potential as indole-3-acetic acid producer was observed in increasing of root length density and diameter class length parameters. While, in general, A. brasilense Sp7 had a greater effect on biomass, probably due to its high ability as nitrogen-fixing bacteria. For K. variicola UC4115, the most consistent data were noticed under organic management, with application at seed level. While, A. brasilense Sp7 showed the greatest performance und

Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) is a severe multisystemic disease characterized by immunological abnormalities and dysfunction of energy metabolism. Recent evidences suggest strong correlations between dysbiosis and pathological condition. The present research explored the composition of the intestinal and oral microbiota in CFS/ME patients as compared to healthy controls. The fecal metabolomic profile of a subgroup of CFS/ME patients was also compared with the one of healthy controls. The fecal and salivary bacterial composition in CFS/ME patients was investigated by Illumina sequencing of 16S rRNA gene amplicons. The metabolomic analysis was performed by an UHPLC-MS. The fecal microbiota of CFS/ME patients showed a reduction of Lachnospiraceae, particularly Anaerostipes, and an increased abundance of genera Bacteroides and Phascolarctobacterium compared to the non-CFS/ME groups. The oral microbiota of CFS/ME patients showed an increase of Rothia dentocariosa. The fecal metabolomic profile of CFS/ME patients revealed high levels of glutamic acid and argininosuccinic acid, together with a decrease of alpha-tocopherol. Our results reveal microbial signatures of dysbiosis in the intestinal microbiota of CFS/ME patients. Further studies are needed to better understand if the microbial composition changes are cause or consequence of the onset of CFS/ME and if they are related to any of the several secondary symptoms.

We assessed the effects of EDTA and selected plant growth-promoting rhizobacteria (PGPR) on the phytoremediation of soils and sediments historically contaminated by Cr, Ni, and Cu. A total of 42 bacterial strains resistant to these heavy metals (HMs) were isolated and screened for PGP traits and metal bioaccumulation, and two Enterobacter spp. strains were finally selected. Phytoremediation pot experiments of 2 months duration were carried out with hemp (Cannabis sativa L.) and giant reed (Arundo donax L.) grown on soils and sediments respectively, comparing in both cases the effects of bioaugmentation with a single PGPR and EDTA addition on plant and root growth, plant HM uptake, HM leaching, as well as the changes that occurred in soil microbial communities (structure, biomass, and activity). Good removal percentages on a dry mass basis of Cr (0.4%), Ni (0.6%), and Cu (0.9%) were observed in giant reed while negligible values (<100‰) in hemp. In giant reed, HMs accumulated differentially in plant (rhizomes > > roots > leaves > stems) with largest quantities in rhizomes (Cr 0.6, Ni 3.7, and Cu 2.2 g plant–1). EDTA increased Ni and Cu translocation to aerial parts in both crops, despite that in sediments high HM concentrations in leachates were measured. PGPR did not impact fine root diameter distribution of both crops compared with control while EDTA negatively affected root diameter class length (DCL) distribution. Under HM contamination, giant reed roots become shorter (from 5.2 to 2.3 mm cm–3) while hemp roots become shorter and thickened from 0.13 to 0.26 mm. A consistent indirect effect of HM levels on the soil microbiome (diversity and activity) mediated by plant response (root DCL distribution) was observed. Multivariate analysis of bacterial diversity and activity revealed not only significant effects of plant and soil type (rhizosphere vs. bulk) but also a clear and similar differentiation of communities between control, EDTA, and PGPR treat

Plastic wastes accumulation in marine environments is becoming a crucial issue; while the toxicity to biota is quite well explored, a gap of knowledge still exists on the role that plastics play in shaping bacterial community structures in marine conditions and their possible transmission to humans. The present study intended first to profile bacterial community structure in floating plastic particles (FP) biofilms and seawater from four Tunisian coastal areas using high-throughput sequencing (HTS) of 16S rDNA. Subsequently, mussels (Mytilus galloprovincialis) as filter feeding organisms were exposed to the FP to broaden the knowledge on the potential role played by environmental plastic particles in shaping bacterial community structures and on their possibility to act as vehicles of bacteria through the food web. The mussels’ microbiota was microbiologically analyzed through HTS, and the Histidine Rich Glycoprotein (HRG) gene expression level was investigated as the main immune response. Our results clearly showed a great variation in the composition of bacterial communities of FP and seawater from different geographical areas. Moreover, the gills of mussels exposed to sterilized seawater and native FP from each site exhibited a wider bacterial biodiversity. The gene expression level of HRG was found to be significantly higher in animals exposed to native FP when compared to sterilized FP. Our results should be carefully considered in view of the Trojan horse effects of FP toward bacteria and its potential toxicity.

The microbial community of a plastic-polluted landfill soil was described. Among the isolated fungi, some of them showed important degradation skills against polyethylene.

The Dry Chaco region is a vast plain that extends throughout north-western Argentina. This region concentrates about 13% of the total Argentine cattle national stock. Beef cattle systems in the north-west of Argentina are highly varied including extensive pastoral systems, silvopastoral systems and intensive grazing systems. Little is known about the impact of these systems on microbial biodiversity and soil quality in this region. This study describes the relationship between soil parameters (FDA, MBC, SOC, CFU, pH, TN and MR) and bacterial communities in silvopastoral systems (SPS) of the Argentine Dry Chaco region. The bacterial composition, evaluated through Illumina MiSeq sequencing of ribosomal 16S amplicons, differed between SPS and pastoral systems, being also influenced by Leucaena and Prosopis tree species. Higher diversity of bacterial populations was detected in SPS with Prosopis. The phylum Firmicutes and Bacilli class were the most abundant in all the treatments. As indicated by Mantel tests, changes in soil bacteria community were related to soil parameters (e.g. SOC and pH). SPSs are viable alternatives for improving soil quality, supported by a significant increase in microbial biomass and activity in comparison with pastoral systems. Furthermore, the different livestock systems strongly affected microbiomes. Overall, the results of the present study suggest that soil bacterial populations are involved in nutrient cycling processes in SPSs of the Argentine Dry Chaco. Further, the composition of soil bacterial communities was related to the analysed soil parameters and tree species.

Probiotics represent a possible strategy for controlling intestinal infections in livestock. Members of the Weissella genus are increasingly being studied for health-related applications in animals and humans. Here we investigated the functional properties of two Weissella cibaria strains isolated from cows reared in Kuwait breeding facilities by combining phenotypic with genomic analyses. W. cibaria SP7 and SP19 exhibited good growth in vitro under acidic conditions and in the presence of bile salts compared to the reference probiotic Lacticaseibacillus (formerly Lactobacillus) rhamnosus GG. Both strains were able to adhere to Caco-2 and HT-29 cell lines, as well as to mucin. The cell-free supernatants of the two isolates exhibited inhibitory activity towards Escherichia coli ATCC 25,922 and Salmonella enterica UC3605, which was ultimately due to the low pH of supernatants. W. cibaria SP19 showed a co-aggregation ability similar to that of L. rhamnosus GG when incubated with S. enterica. Whole genome sequencing and analysis revealed that both strains harbored several genes involved in carbohydrate metabolism and general stress responses, indicating bacterial adaptation to the gastrointestinal environment. We also detected genes involved in the adhesion to host epithelial cells or extracellular matrix. No evidence of acquired antibiotic resistance or hemolytic activity was found in either strain. These findings shed light on the potential of W. cibaria for probiotic use in livestock and on the mechanisms underlying host-microbe interaction in the gut. W. cibaria` strain SP19 exhibited the best combination of in vitro probiotic properties and genetic markers, and is a promising candidate for further investigation.

Pumpkin leaves (Cucurbita sp.) were spontaneously fermented using the submerged method with 3% NaCl and 3% sucrose. Negative controls were set up, consisting of leaves with no additions.

Late-blowing – severe cheese spoilage caused by clostridia – is a long-standing problem of economic importance for dairy processors. However, there is still a paucity of relevant data on clostridia in cheese that would allow some tailored intervention. The main aim of this study was to identify and quantify clostridia in late-blown cheese using a polyphasic methodological approach. Fifty-three cheeses of different origins were analysed using culture-dependent (MPN, enrichment, molecular identification of isolates) and culture-independent methods (real-time PCR, PCR-DGGE and Illumina 16S rDNA sequencing). Using culture-dependent methods, clostridial isolates were collected from several cheese samples, while fewer positive results were obtained with the samples when using the MPN procedure than real-time PCR or PCR-DGGE. In contrast to other studies, an extremely low diversity of Clostridium species was observed. Surprisingly, Illumina 16S rDNA amplicon sequencing revealed relative abundances of clostridia below the detection limit despite apparent cheese spoilage.

The development of biopolymers has raised issues about their recalcitrance in the environment. Their disposal is mainly carried out with the organic fraction of municipal solid waste (OFMSW) through thermophilic anaerobic digestion and aerobic composting, bioprocesses aimed at turning organic matter into biogas and compost. However, the effects of biopolymers on OFMSW treatment, on the final compost and on the microbial communities involved are partly unexplored. In this study, the OFMSW treatment was reproduced on a laboratory-scale respecting real plant conditions and testing the impacts of mixing polylactic acid (PLA) and starch-based bioplastic (SBB) separately. The dynamics of bacterial, archaeal and fungal communities during the process was screened by high-throughput sequencing (HTS) of phylogenetic amplicons. Starch-based bioplastic showed a minor and heterogeneous microbial diversity between the anaerobic and aerobic phases. Contrariwise, PLA treatment resulted in wider and more diverse bacterial and fungal communities for the compost and the aerobic biofilm. Since the biodiversity in compost may play a crucial role in its stability and safety, the modulation of environmental microbial communities induced by higher concentrations of PLA in OFMSW treatment can pose relevant issues.

Conventional plastics and bioplastics are known to accumulate in aquatic ecosystems, emerging as new surfaces for biofilm formation and gene exchanges. On the other hand, the fate of non-conventional bioplastics in the marine environment is still unclear. In this study we have measured, by means of crystal violet test and scanning electron microscopy (SEM), the ability of two model bacteria, Vibrio harveyi and Enterococcus faecalis, to form biofilms on low-density polyethylene (PE), polylactic acid (PLA) and starch-based bioplastic (SBB) surfaces. Experiments were conducted in artificial sea water, incubating squares of 3 cm2 of the three plastics with the two model microorganisms and sampling overnight, and at 3 and 6 days. The presence of biofilms on plastic surfaces was detected from day one of incubation and SBB was the material with the highest biofilm formation. E. faecalis formed the thickest biofilm after 3 days with PLA and SBB, but did not remain stable, and after 6 days with PE. The maximum biofilm formation of V. harveyi was obtained overnight with SBB and PE, and after 3 days with PLA. Our data indicate that both plastic and bioplastics support the formation of biofilms of model pathogenic bacteria, highlighting potential concerns for human health.

This review describes the researches performed in the last years to assess the impact of pesticide sub-lethal doses on soil microorganisms and non-target organisms in agricultural soil ecosystems. The overview was developed through the careful description and a critical analysis of three methodologies based on culture-independent approaches involving DNA extraction and sequencing (denaturing gradient gel electrophoresis, DGGE; next-generation sequencing, NGS) to characterize the microbial population and DNA damage assessment (comet assay) to determine the effect on soil invertebrates. The examination of the related published articles showed a continuous improvement of the possibility to detect the detrimental effect of the pesticides on soil microorganisms and non-target organisms at sub-lethal doses, i.e., doses which have no lethal effect on the organisms. Considering the overall critical discussion on microbial soil monitoring in the function of pesticide treatments, we can confirm the usefulness of PCR-DGGE as a screening technique to assess the genetic diversity of microbial communities. Nowadays, DGGE remains a preliminary technique to highlight rapidly the main differences in microbial community composition, which is able to give further information if coupled with culture-dependent microbiological approaches, while thorough assessments must be gained by high-throughput techniques such as NGS. The comet assay represents an elective technique for assessing genotoxicity in environmental biomonitoring, being mature after decades of implementation and widely used worldwide for its direct, simple, and affordable implementation. Nonetheless, in order to promote the consistency and reliability of results, regulatory bodies should provide guidelines on the optimal use of this tool, strongly indicating the most reliable indicators of DNA damage. This review may help the European Regulation Authority in deriving new ecotoxicological endpoints to be included in the Regi

Biodegradable polymers were introduced in the past decades in order to address the issue of plastic pollutions, and these materials have thus required the development of methodologies to understand and evaluate their disintegration. The aim of this study was to simulate the organic fraction of municipal solid waste (OFMSW) treatment in laboratory-scale and to assess the biodegradation of poly(lactic acid) (PLA) water bottles and starch-based bags under real industrial conditions of anaerobic digestion and aerobic composting. Methane production and loss of mass were determined to estimate the anaerobic degradation; whereas phytotoxicity tests were carried out to provide an evaluation of the compost quality. To visualize the effects on the materials, SEM analyses, differential scanning calorimetry (DSC) and FT-IR/ATR spectroscopy were performed. Different outcomes were found for the tested bioplastics products. PLA bottles didn’t biodegrade under anaerobic conditions and the pieces appeared wrap up at the end, while starch-based bioplastic bags performed 85.79% of disintegration degree. CH4 production was between 40 and 50% for both the products. Phytotoxicity test on the final composts highlighted negative effects on both selected seeds for PLA solutions. Water-soluble lactic acid from degraded PLA bottle significantly reduced the pH of compost affecting seed germination and germination indexes. Both bioplastics showed chemical modification according to DSC and FT-IR/ATR analyses.

Nowadays, agriculture is facing the great challenge of climate change which puts the productivity of the crops in peril due to unpredictable rain patterns and water shortages, especially in the developing world. Besides productivity, nutritional values of the yields of these crops may also be affected, especially under low mechanization and the low water availability conditions of the developing world. Conservation agriculture (CA) is a topic of emerging interest due to the provision of adequate yields and reduced environmental impact, such as greenhouse gas emissions, by being based on three main principles: minimum soil disturbance (reduced or no tillage), cover crop maintenance, and crop rotation. The aim of this study was to assess the impact of CA management on the growth performance and the nutritional profile of cowpea (Vigna unguiculata L. Walp), a pulse of African origin, commonly known as black eye bean under field conditions. A field experiment was designed to assess the effect of conventional tillage (CT) and no-tillage (NT) combined with the usage of a set of cover crops, coupled to normal and deficient water regimes. Cowpea was revealed to be able to grow and yield comparably at each level of the treatment tested, with a better ability to face water exhaustion under CA management. After a faster initial growth phase in CT plots, the level of adaptability of this legume to NT was such that growth performances improved significantly with respect to CT plots. The flowering rate was higher and earlier in CT conditions, while in NT it was slower but longer-lasting. The leafy photosynthetic rate and the nutritional profile of beans were slightly influenced by tillage management: only total starch content was negatively affected in NT and watered plots while proteins and aminoacids did not show any significant variation. Furthermore, significantly higher carbon and nitrogen concentration occurred in NT soils especially at the topmost (0–5 cm) soil horizon. Th

In the former Carbochimica site of Fidenza, a bioremediation approach was developed using the technique of biodegradation of pollutants thanks to a selected autochthonous bacterial-fungal consortium. The soil was heavily polluted up to values of total hydrocarbon equal to 1800 mg/kg. The consortium was selected from the microorganism living in the Fidenza soil, bioaugmented and finally reinoculated in the bio-pile for soil treatment. The approach is absolutely innovative, due to the presence not only of bacterial strains but also for the use of fungal strains operating in synergy with the bacteria. The first data from the trials show an effective soil remediation performance. The LCA analysis allowed to make a global assessment of the environmental impacts of the bio-pile remediation treatment scenario compared to the no-action scenario. Impacts were assessed on 18 impact categories at the midpoint level according to the ReCiPe method. For the bio-augmented bio-pile remediation, the results showed a value in the climate change category of 10 kg CO2 for each ton of remediated soil, and at the same time improvement in the categories relating to the toxicity at the local level.

Fifteen bifidobacterial strains were obtained from faeces of Rousettus aegyptiacus; after grouping them by RAPD PCR only eight were selected and characterized. Analysis of 16S rRNA and of five housekeeping (hsp60, rpoB, clpC, dnaJ, dna G) genes revealed that these eight strains were classified into five clusters: Cluster I (RST 8 and RST 16T), Cluster II (RST 9T and RST 27), Cluster III (RST 7 and RST 11), Cluster IV (RST 19), Cluster V (RST 17) were closest to Bifidobacterium avesanii DSM 100685T (96.3%), Bifidobacterium callitrichos DSM 23973T (99.2% and 99.7%), Bifidobacterium tissieri DSM 100201T (99.7 and 99.2%), Bifidobacterium reuteri DSM 23975 T (98.9%) and Bifidobacterium myosotis DSM 100196T (99.3%), respectively. Strains in Cluster I and strain RST 9 in Cluster II could not be placed within any recognized species while the other ones were identified as known species. The average nucleotide identity values between two novel strains, RST 16T and RST 9T and their closest relatives were lower than 79% and 89%, respectively. In silico DNA-DNA hybridization values for those closest relatives were 32.5 and 42.1%, respectively. Phenotypic and genotypic tests demonstrated that strains in Cluster I and RST 9T in Cluster II represent two novel species for which the names Bifidobacterium vespertilionis sp. nov. (RST 16T=BCRC 81138T=NBRC 113380T=DSM 106025T ; RST 8=BCRC 81135=NBRC 113377) and Bifidobacterium rousetti sp. nov. (RST 9T=BCRC 81136T=NBRC 113378T=DSM 106027T) are proposed.

Lo sviluppo sostenibile dei sistemi alimentari è una delle più importanti sfide attuali a livello globale, più volte sottolineata nei Sustainable Development Goals (griggs et al., 2013). Nel caso dei Paesi dell’Africa sub-sahariana, tale sfida si inserisce in un quadro più ampio: la lotta alla malnutrizione e sottonutrizione, la salvaguardia delle risorse naturali e della fertilità del suolo, la tutela e la valorizzazione della biodiversità locale, l’incremento della produttività agraria, la conoscenza ed il rispetto delle culture locali, la necessità di crescita economica, la lotta ai cambiamenti climatici. In altre parole, la sfida è quella di promuovere modelli di sviluppo sostenibile che si appoggino equamente sui 3 principali pilastri: ambientale, sociale ed economico (WCED, 1987). Vengono qui descritti gli obiettivi che l’Università Cattolica del Sacro Cuore sta portando avanti nell'ambito del progetto SASS (Sistemi Alimentari e Sviluppo Sostenibile), un progetto biennale finanziato nel 2017 dal Ministero dell’Istruzione, dell’Iniversità e della Ricerca, al quale lavorano, sotto il coordinamento dell’università di Milano Bicocca (uNIMIB), anche l’università degli Studi di Pavia (uNIPV), l’università degli Studi di Scienze gastronomiche di Pollenzo (uNISg) e l’European Centre for Development Policy Management (ECDPM) di Maastricht. Il progetto ha identificato come area di studio il kenya, nella zona del lago di Naivasha, e la tanzania, nella zona di Arusha e del corridoio di Sagcot, un’importante zona di sviluppo agricolo.

The Lactobacillus vaginalis LMG S-26419 strain, also named CBA-L88 (BV2), was isolated at the AAT-Advanced Analytical Technologies laboratories from a vaginal swab obtained from a healthy woman. The total genome size is 1,806,242 bp with a G+C content of 40.6%.

Supplementing kindergarten children during a cold season with a prebiotic inulin-type fructans product with shorter and longer fructan chains has been shown to reduce febrile episodes requiring medical attention and to lower the incidence of sinusitis. These beneficial effects may be connected to the specific modulation of children’s gut microbiota. By applying quantitative and qualitative microbiota analysis this study aimed at characterising the gut microbiota composition and at exploring effects of prebiotic intervention on the gut microbiota during a 24-weeks intervention and during antibiotic treatment in healthy children. The study was a randomised, placebo-controlled trial with 258 healthy children aged 3 to 6 years consuming 6 g/day prebiotic inulin-type fructans or maltodextrin. During the course of the study, faecal samples were collected and subject to targeted qPCR analysis and phylogenetic profiling by multiplexed high throughput sequencing of the prokaryotic 16S rRNA gene PCR amplicons. The microbiota composition of the cohort could be clustered into three distinct constellations (enterotypes). Prebiotic intake resulted in a selective modulation of the gut microbiota composition. Relative abundance of Bifidobacterium was significantly higher in the prebiotic group (n=104) compared to control group (n=105) and this effect was found for all three enterotypes. Antibiotic administration decreased the relative abundance of Bifidobacterium in both groups. Nonetheless, children of the prebiotic group receiving antibiotic treatment displayed significantly higher levels of Bifidobacterium than children receiving the placebo control. Prebiotic supplementation induced specific changes in the gut microbiota composition of children aged 3 to 6 years. Moreover, it attenuated antibiotic-induced disturbances in the gut microbiota composition as shown by higher relative abundance of bifidobacteria at the end of the antibiotic treatment in the prebiotic group. With the

Synthetic pesticides may have non-target effects on soil microorganisms which have been identified as a specific protection goal in pesticide environmental risk assessment. Most studies to date have focused on the effects of synthetic pesticides on soil microorganisms, whereas little is known about the response of the soil microbial community to the so-called low-risk pesticide classes. The main objective of this study was to assess the impact of a botanical (azadirachtin) and a low-dose pesticide (trifloxystrobin), applied as commercial formulations, on soil microbial functions. In a microcosm study, pesticides were applied in soil at increasing dose rates (up to ×100 the recommended dose rate). Their dissipation and the formation of the major transformation product (TP) of trifloxystrobin were determined. Enzymatic activities and the abundance of key functional microbial groups were measured via fluorometric assays, potential nitrification (PNT) and q-PCR. Trifloxystrobin and azadirachtin did not persist in soil at all dose rates with DT 50s of 1.1–1.4 and 1.3 days respectively. No pesticide dose-dependent inhibitory effects on the activity of soil enzymes, the abundance of ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA), sulfur-oxidizing bacteria (SOB) and on PNT were seen. Instead the application of both pesticides at all dose rates stimulated PNT. Trifloxystrobin was transformed to trifloxystrobin acid (TFSA), which persisted in soil. However its formation did not correlate with adverse effects on soil microbial functions. We provide first evidence that trifloxystrobin and azadirachtin do not impose unacceptable effects on soil microbial functions even at high dose rates.

Autochthonous bioaugmentation, by exploiting the indigenous microorganisms of the contaminated environment to be treated, can represent a successful bioremediation strategy. In this perspective, we have assessed by molecular methods the evolution of bacterial and fungal communities during the selective enrichment on different pollutants of a soil strongly polluted by mixtures of aliphatic and polycyclic hydrocarbons. Three consecutive enrichments were carried out on soil samples from different soil depths (0–1, 1–2, 2–3 m), and analyzed at each step by means of high-throughput sequencing of bacterial and fungal amplicons biomarkers. At the end of the enrichments, bacterial and fungal contaminants degrading strains were isolated and identified in order to (i) compare the composition of enriched communities by culture-dependent and culture-independent molecular methods and to (ii) obtain a collection of hydrocarbon degrading microorganisms potentially exploitable for soil bioremediation. Molecular results highlighted that for both bacteria and fungi the pollutant had a partial shaping effect on the enriched communities, with paraffin creating distinct enriched bacterial community from oil, and polycyclic aromatic hydrocarbons generally overlapping; interestingly neither the soil depth or the enrichment step had significant effects on the composition of the final enriched communities. Molecular analyses well-agreed with culture-dependent analyses in terms of most abundant microbial genera. A total of 95 bacterial and 94 fungal strains were isolated after selective enrichment procedure on different pollutants. On the whole, isolated bacteria where manly ascribed to Pseudomonas genus followed by Sphingobacterium, Bacillus, Stenothrophomonas, Achromobacter, and Serratia. As for fungi, Fusarium was the most abundant genus followed by Trichoderma and Aspergillus. The species comprising more isolates, such as Pseudomonas putida, Achromobacter xylosoxidans and Ochromobactrum

Pesticides are key stressors of soil microorganisms with reciprocal effects on ecosystem functioning. These effects have been mainly attributed to the parent compounds, while the impact of their transformation products (TPs) has been largely overlooked. We assessed in a meadow soil (soil A) the transformation of iprodione and its toxicity in relation to (i) the abundance of functional microbial groups, (ii) the activity of key microbial enzymes, and (iii) the diversity of bacteria, fungi, and ammonia-oxidizing microorganisms (AOM) using amplicon sequencing. 3,5-Dichloroaniline (3,5-DCA), the main iprodione TP, was identified as a key explanatory factor for the persistent reduction in enzymatic activities and potential nitrification (PN) and for the observed structural changes in the bacterial and fungal communities. The abundances of certain bacterial (Actinobacteria, Hyphomicrobiaceae, Ilumatobacter, and Solirubrobacter) and fungal (Pichiaceae) groups were negatively correlated with 3,5-DCA. A subsequent study in a fallow agricultural soil (soil B) showed limited formation of 3,5-DCA, which concurred with the lack of effects on nitrification. Direct 3,5-DCA application in soil B induced a dose-dependent reduction of PN and NO3 --N, which recovered with time. In vitro assays with terrestrial AOM verified the greater toxicity of 3,5-DCA over iprodione. "Candidatus Nitrosotalea sinensis" Nd2 was the most sensitive AOM to both compounds. Our findings build on previous evidence on the sensitivity of AOM to pesticides, reinforcing their potential utilization as indicators of the soil microbial toxicity of pesticides in pesticide environmental risk analysis and stressing the need to consider the contribution of TPs in the toxicity of pesticides on the soil microbial community.

Polyethylene (PE), the most common petroleum-based plastic, is strongly recalcitrant to degradation. Despite this, recent evidences showed that a few microbial strains can partially degrade PE pre-oxidized by abiotic processes. Here, we investigated plastic samples from an abandoned landfill, with the aim of elucidating the ecology of soil microorganisms able to grow on the plastics and to correlate them with plastic degradation levels. Isolations were carried after detachment of the biofilm from the plastic surfaces and se- rial dilutions on selective agar plates of mineral medium with paraffin as the only carbon source. Microbial DNA derived from the plastic surfaces, the landfill soil and an uncontam- inated neighboring agricultural soil was also analyzed by Illumina sequencing of 16S rRNA amplicons. A total of 49 strains growing on paraffin were identified: the most representative genus is Bacillus genus with 12 different species represented, followed by Pseudomonas, Lysini- bacillus, Comanomonas and Acinetobacter. Differential scanning calorimetric analysis of the plastic samples showed an additional shoul- der melting peak with various enthalpies besides the main melting peak, implying the plastic exhibited different degrees of degradation. In parallel, Illumina 16S rRNA analyses showed that the different plastics hosted different microbial communities, and that the bacterial community derived from plastic sample with the highest degradation level was the most similar to that of the soil derived from contaminated landfill. Results point to an interesting correlation between the level of plastic degradation and the composition of the microbial biofilm.

NA

N/A

Environmental microbial communities are key players in the transformation and miner- alization of hydrocarbon pollutants. The aim of this study was to assess changes in bacterial abundance and diversity during the degradation of Tunisian Zarzatine oil by four indigenous bacterial consortia isolated from different polluted environmental matrix (a petroleum sta- tion soil, refinery reservoir soil, harbor sediment and harbor seawater). The microcosms were inoculated for two months with either a defined bacterial consortium and Zarzatine crude oil as only carbon and energy source. The microbial community dynamics was evaluated weekly in microcosms using Illumina 16S rRNA gene sequencing. An average of 7020 sequences per samples were obtained, the measured coverage was higher than 97% and more than 60% of sequence were correctly classified at species level. Degrading consortia enriched from soil and sediments were dominated by species belonging to Pseudomonas and Acinetobacter gen- era, while in the seawater-derived consortia Dietzia, Fusobacterium and Dicoplana emerged as dominant genera. We identified specific OTUs whose relative abundances bloomed from small to high percentages and were significantly correlated to total petroleum degradation: an OTU classified as Dietzia daqingensis in the seawater microcosms, and three OTUs classified as Acinetobacter venetianus in all two soils and sediment derived microcosms. Interestingly, a comparative analysis showed that this was the same OTU in all 3 microcosms which were derived from consortia isolated from different types (soil or sediment) and location. The work provides detailed insights about the modulation of bacterial communities involved in petroleum biodegradation.

LIFE-BIOREST (www.lifebiorest.com) is a EU-project aimed at the remediation of a soil polluted by PHAs, BTEX and alkanes through the application of selected consortia of fungi and bacteria. In the first phase of the project, we have isolated from the polluted soil about 220 fungal and 140 bacterial strains with degrading abilities. Most of the fungal strains belonged to Ascomycetes (mainly Aspergillus, Cladosporium, Fusarium and Scedosporium genera) even though about 20 Basidiomycetes were also isolated. Regarding bacteria, the most abundant genus was Pseudomonas followed by Achromobacter, Stenotrophomonas and Ochrobactrum. The isolates were obtained by means of a liquid enrichment approach on target contami- nants (naphthalene, pyrene, phenanthrene, benzene, alkanes and oil extracted from the soil): the enrichment lasted 3 weeks, and sub-culturing was carried out once a week. Since the pollution in the test soil involved several meters of depth, enrichments were carried out sep- arately using as inoculum homogenized soil samples from the 0-1, the 1-2 and 2-3 m depth. A total of 18 enrichment consortia were produced (6 target contaminants X 3 soil depths) for bacteria and other 18 for fungi, and sampled at day 0, 7, 14 and 21, giving a total of 144 samples. For each of these samples, DNA was extracted, amplified respectively for bacterial (16S) and fungal (ITS) biomarkers, and the resulting amplicons sequenced in Illumina. Results will be presented with the aim of assessing the ecological evolution of the microbial communities (bacteria and fungi) during the selective enrichment procedure in presence of different pollutants.

LIFE-BIOREST (www.lifebiorest.com) is a EU-project aimed to remediate a soil polluted by PHAs, BTEX and alkanes through the application of selected consortia of fungi and bacteria. The first phase of the project was focused on the characterization and isolation of the autochthonous microbial community that naturally populates this extreme environment. About 220 fungal and 140 bacterial strains with degrading abilities have been isolated from the polluted soil. Most of the fungal strains belonged to Ascomycetes (mainly Aspergillus, Cladosporium, Fusarium and Scedosporium genera) even though about 20 Basidiomycetes were also isolated. Regarding bacteria, the most abundant genus was Pseudomonas followed by Achromobacter, Stenotrophomonas and Ochrobactrum. The isolates were obtained by means of a liquid enrichment approach on target contami- nants (naphthalene, pyrene, phenanthrene, benzene, alkanes and oil extracted from the soil): the enrichment lasted 3 weeks, and sub-culturing was carried out once a week. Since the pollution in the sampled soil involved several meters of depth, enrichments were carried out separately using as inoculum homogenized soil samples from the 0-1, the 1-2 and 2-3 m depth. A total of 18 enrichment consortia were produced (6 target contaminants X 3 soil depths) for bacteria and other 18 for fungi, and sampled at day 0, 7, 14 and 21, giving a total of 144 samples. For each of these samples, DNA was extracted, amplified respectively for bacterial (16S) and fungal (ITS) biomarkers, and the resulting amplicons sequenced in Illumina. Results will be presented with the aim of assessing the ecological evolution of the microbial communities (bacteria and fungi) during the selective enrichment procedure in presence of different pollutants.

Polyethylene (PE) is the most common petroleum-based plastic. It accumulates at a rate of several millions of tons per year since its recalcitrance to both biotic and abiotic degradation. Despite these difficulties, recent evidences showed that some microbial strains can partially degrade PE pre-oxidized by abiotic processes. Here, we investigated plastic samples from an abandoned landfill, with the aim of elucidating the ecology of soil microorganisms able to grow on the plastics and to correlate them with plastic degradation levels. Microbial DNA derived from the plastic surfaces, the landfill soil and an uncontaminated neighboring agricultural soil was analyzed by Illumina high-throughput sequencing of 16S rRNA amplicons. A first isolation was carried after detachment of the biofilm from the plastic surfaces and serial dilutions on selective agar plates of mineral medium with paraffin as the only carbon source. The analysis on total microbial community through Illumina 16S rRNA sequencing shows that different PE samples host different species. This confirms the results from differential scanning calorimetric analysis of the material that shows an additional shoulder melting peak with various enthalpies besides the main melting peak, implying the plastic exhibited different degrees of degradation, suggesting that plastics seems to be able to select microbiological activity that correlates with PE degradation level. Interestingly, the microbial population derived from plastic sample with the highest degradation level is very similar to that of the soil derived from contaminated landfill. The first cultured selection based on the ability to grow on paraffin of the microbial community derived from the biofilm on plastics surfaces allows us to identify by RAPD (Random Amplified Polymorphic DNA) analysis a total of 49 different strains. The most representative are Bacillus genus with 12 different species represented, followed by Pseudomonas, Lysinibacillus, Comanomonas

The present study was carried out to assess the effects of EDTA and selected bacteria on the phytoremediation of soils and sediments historically contaminated by Cu, Cr and Ni. A total of 42 bacterial strains resistant to these three metals were isolated and screened for plant growth promoting traits and metals bioaccumulation, resulting in two selected Enterobacter spp. strains. Phytoremediation pot experiments of 3 months duration were carried out with hemp (Cannabis sativa L.) and giant reed (Arundo donax L.) grown on soils and sediments respectively: in both cases the effects of inocula with the selected bacteria and addition of EDTA were compared. Microbial inocula significantly increased leaf and stem biomass in giant reed, while in hemp no differences were detected. Plant physiological parameters were not significantly different between plants grown on contaminated and non-contaminated soils or sediments. Leaf area in inoculated pots was also significantly higher than in controls for both plants. In hemp, bioaccumulation followed the order Ni>Cu>Cr, with higher accumulation in roots than in stems, flowers and leaves. EDTA addition significantlyincreased above biomass accumulation of Ni and Cu . In hemp addition of the microbial inoculum did not affect remediationpotential; removal percentages were below 0.5% for all three metals. In giant reed the highest accumulation were found in below-ground biomass (rhizomes and roots). Removal of metals by rhizomes and roots was significantly increased with EDTA or microbial inoculum. Leaching of metals with irrigation water was was greatly enhanced with the addition of EDTA. The higest removal of metals, up to 7%, were obtained with giant reed combined with chemical leaching. This approach could be used to lower the heavy metal concentration of the target site to the levels required for public use in less than 5 years.