The climate crisis is changing temperature regimes worldwide, threatening global viticulture and wine production, as temperature is a primary driver of grape development. In Atlantic Canada, temperatures are projected to increase, inducing premature grape ripening. This can impact their biochemical profiles and, consequently, the quality of the vines, in terms of plant health and fruit yield, and therefore the quality of the wines produced. Temperature is also a key factor in determining the composition fungal communities on the leaves (phyllosphere) and fruits (carposphere) of grape vines. Therefore, to better understand how these communities might change under potential future temperature regimes, we experimentally manipulated grapevines (Vitis sp. cv. L’Acadie blanc) in the field. We used on-the-row mini-greenhouses to increase the temperature at different developmental or phenological stages of the fruits, and across the whole season. Phyllosphere and carposphere were sampled at four developmental stages, their DNA was extracted, and the fungal communities were identified via ITS metabarcoding. We found that phyllosphere and carposphere had significantly different community composition, which remained relatively stable throughout plant development. Increased temperature treatments had the most significant effect on fungal phyllosphere communities; we observed that phyllosphere samples exposed to higher temperatures before the onset of ripening maintained fungal communities with higher species richness throughout development. Our analysis showed that the increase in fungal diversity among phyllopshere communities corresponds to enrichments in potential phytopathogenic fungal taxa. However, this increase in phyllosphere fungal diversity was not conserved at other growth stages when the leaves developed at higher temperatures for the whole season. The results of this study will contribute to better understanding the impact of the climate crisis on grapevine phyllosphere and carposphere fungal community composition and assembly. This will allow producers to better adapt to climate variability and to better understand the role that these communities could play on grapevine health.

Municipal biosolids (MBS) are suggested to be abundant, sustainable, inexpensive fertilisers, rich in phosphorus and nitrogen. However, MBS can also contain glyphosate and phosphonates that can degrade to AMPA. Glyphosate-based herbicides (GBH) are used in field crops all over the world. Most glyphosate generally degrades within a few weeks, mainly as aminomethylphosphonic acid (AMPA). AMPA is more persistent than glyphosate, and can accumulate from one crop year to the next. AMPA is phytotoxic even to glyphosate-resistant crops. The aims of this study were to assess whether MBS applications constitute: 1) an additional source of glyphosate and AMPA to agricultural soils with respect to GBH, 2) a significant source of trace metals, and 3) a partial replacement of mineral fertilisation while maintaining similar yields. To this end, four experimental agricultural sites were selected in Que ' bec (Canada). Soil samples (0-20 cm) were collected to estimate the as yet unmeasured contribution of MBS application to glyphosate and AMPA inputs in agricultural soils. MBS applied in 2021 and 2022 had mean concentrations of 0.69 +/- 0.53 mu g glyphosate/dry g and 6.26 +/- 1.93 mu g AMPA/dry g. Despite the presence of glyphosate and AMPA in MBS, monitoring of these two compounds in corn and soybean crops over two years showed no significant difference between plots treated with and without MBS applications. For the same site, yields measured at harvest were similar between treatments. MBS application could thus represent a partial alternative to mineral fertilisers for field crops, while limiting the economic and environmental costs associated with their incineration and landfilling. It is also an economic advantage for agricultural producers given the possibility of using fewer mineral fertilisers and therefore reducing the environmental impact of their use.

Green initiatives and phytotechnologies, such as phytoremediation, hold great potential for the sustainable management of contaminated brownfields. One impediment to these initiatives is the lack of alternatives for the produced biomass due to the potential contamination of plants by trace elements. We conducted an experiment to quantify the accumulation and the translocation patterns of trace elements in the aboveground parts of fifteen desirable plants species used for these kinds of initiatives, i.e. urban predominance, ecological relevance, edibility, commercial prospective, and phytoremediation potential. The experiment was set-up in a tunnel-type greenhouse in which plants were grown in pots filled with contaminated urban soil containing Cu, Zn, Se, Ag and spiked with Cd. Our results indicated that different species exhibited differential abilities to accumulate and translocate trace elements in their aboveground biomass and furthermore, exhibited different bioconcentration factors. A clear exclusion of Cd allocation was observed in fruits and flowers. However, Cd content in edible parts was still above the standard recommendations for human consumption. Our results suggest potential candidates for phytoremediation by revealing different accumulation patterns, also highlighting the importance of characterizing trace elements in the soil for selecting the appropriate plant species based on project's needs.

Willows can alleviate soil salinisation while generating sustainable feedstock for biorefinery, yet the metabolomic adaptations underlying their salt tolerance remain poorly understood. Testing two environmentally abundant salts, the response of Salix miyabeana was assessed after treatment with a moderate concentration of NaCl, and both moderate and high concentrations of Na2SO4 in a 12-week pot trial. Willows tolerated salts across all treatments (up to 9.1dS m-1 soil ECe), maintaining photosynthesis and biomass while selectively partitioning ions, confining Na+ to roots and accumulating Cl- and SO 2- in the canopy, and adapting to osmotic stress via reduced stomatal conductance. Untargeted LC-MS/MS captured over 5,000 putative compounds, characterising the baseline willow metabolome, including 278 core compounds constitutively produced across organs. Comparative statistical analyses revealed widespread metabolic reprogramming in response to soil salinity, altering 28% of the overall metabolome, and highlighting organ-tailored strategies. Comparing both salt forms at equimolar sodium, generalised salinity responses were limited to 3% of the metabolome, predominantly in roots. Anion-specific metabolomic responses were more extensive, with NaCl reducing carbohydrates and TCA intermediates, thereby exerting pressure on carbon and energy resources, alongside the accumulation of root structuring compounds, antioxidants flavonoids, and fatty acids. In contrast, Na2SO4 salinity triggered accumulation of sulphur-containing larger peptides, suggesting that excess sulphate incorporation leverage ion toxicity to produce specialized salt-tolerance associated metabolites. This high-depth picture of the willow metabolome underscores the importance of capturing plant adaptations to salt stress at organ-scale and considering ion-specific contributions to soil salinity. ### Competing Interest Statement The authors have declared no competing interest.

Wastewater treatment is a necessary step to avoid environmental impacts of water consumption and usage. Traditional approaches are expensive and are limited to developed countries. Phytofiltration using fast-growing trees and shrubs like willows potentially offer an alternative. This paper aims to determine if wastewater treatment using phytofiltration can provide complementary environmental and economic benefits for rural communities in a Nordic climate such as the province of Québec, Canada. It looks at different perspectives of the wastewater treatment solution in a local and rural context. Based on life cycle analysis (LCA) and life cycle cost analysis (LCC), we found that, for an exemplar Québec municipality, the conventional wastewater treatment scenario impacted more on climate change, ecosystem quality and human health than the two phytofiltration of wastewater scenarios studied, where impact is highly dependant on the biomass valorization. The net present cost of the phytofiltration scenarios were lower than typical conventional treatment in Québec. For a biomass producer, conventional biomass production had the highest environmental impact on ecosystem quality, while biomass production from phytofiltration had the highest environmental impact on climate change, human health, and resources. We demonstrate that the phytofiltration is a viable and multifunctional technology that could provide good incentives for a local biomass value chain. it allows to both alleviate wastewater treatment burden and provide affordable biomass for bioenergy development for rural communities. Mobilizing local stakeholders will be key to make phytofiltration an alternative solution for both environmental burden alleviation and rural economic development.

Arsenic (As) contamination of soils threatens the health of millions globally through accumulation in crops. While plants detoxify As via phytochelatin (PC) complexation and efflux of arsenite from roots, arsenite efflux mechanisms are not fully understood. Here, white lupin (Lupinus albus) was grown in semi-hydroponics, and exudation of glutathione (GSH) derivatives and PCs in response to As was measured using LC-MS/MS. Inhibiting synthesis of the PC precursor GSH with l-buthionine sulfoximine (BSO) or ABC transporters with vanadate drastically reduced (>22%) GSH derivative and PC2 exudation, but not PC3 exudation. This was accompanied by As hypersensitivity in plants treated with BSO and moderate sensitivity with vanadate treatment. Investigating As-PC complexation revealed two distinct As-PC complexes, As bound to GSH and PC2 (GS-As-PC2) and As bound to PC3 (As-PC3), in exudates of As-treated lupin plants. Vanadate inhibited As-PC exudation, while BSO inhibited both the synthesis and exudation of As-PC complexes. These results demonstrate a role for GSH derivatives and PC exudation in lupin As tolerance and reveal As-PC exudation as a new potential mechanism contributing to active As efflux in plants. Overall, this study uncovers insights into rhizosphere As detoxification with potential to help mitigate pollution and reduce As accumulation in crops.

Reducing the environmental impact of Canadian field crop agriculture, including the reliance on conventional synthesised fertilisers, are key societal targets for establishing long-term sustainable practices. Municipal biosolids (MSB) are an abundant, residual organic material, rich in phosphate, nitrogen and other oligo-nutrients, that could be used in conjunction with conventional fertilisers to decrease their use. Though MBS have previously been shown to be an effective fertiliser substitute for different crops, including corn and soybean, there remain key knowledge gaps concerning the impact of MBS on the resident soil bacterial communities in agro-ecosystems. We hypothesised that the MBS fertiliser amendment would not significantly impact the structure or function of the soil bacterial communities, nor contribute to the spread of human pathogenic bacteria, in corn or soybean agricultural systems. In field experiments, fertiliser regimes for both crops were amended with MBS, and compared to corn and soybean plots with standard fertiliser treatments. We repeated this across four different agricultural sites in Quebec, over 2021 and 2022. We sampled MBS-treated, and untreated soils, and identified the composition of the soil bacterial communities via 16S rRNA metabarcoding. We found no indication that the MBS fertiliser amendment altered the structure of the soil bacterial communities, but rather that the soil type and crop identities were the most significant factors in structuring the bacterial communities. Moreover, there was no evidence that the MBS-treated soils were enriched in potential human bacterial pathogens over the two years of our study. Our analysis indicates that not only can MBS function as substitutes for conventional, synthesised fertilisers, but that they also do not disrupt the structure of the resident soil bacterial communities in the short term. Finally, we suggest that the use of MBS in agro-ecosystems poses no greater concern to the public than existing soil bacterial communities. This highlights the significant role MBS could potentially have in reducing the use of conventional industrial fertilisers and improving agricultural production, without risking environmental contamination.

The climate crisis is changing temperature regimes worldwide, threatening global viticulture and wine production, as temperature is a primary driver of grape development. In Atlantic Canada, temperatures are projected to increase, inducing premature grape ripening, which can impact their biochemical profiles and, consequently, the quality of the vines and wines produced. Temperature is also a key factor in determining the composition and structure of resident fungal communities on the leaves (phyllosphere) and fruits (carposphere) of grape vines. Therefore, to better understand how these communities might change under potential future temperature regimes, we experimentally manipulated grapevines (Vitis sp. cv. L'Acadie blanc) in the field. We used on-the-row mini-greenhouses to increase the temperature at different developmental, or phenological, stages of the fruits, and across the whole season. Phyllosphere and carposphere were sampled at four developmental stages, their DNA was extracted, and the fungal communities were identified via ITS metabarcoding. We found that phyllosphere and carposphere had significantly different community composition, which remained relatively stable throughout plant development. Increased temperature treatments had the most significant effect on fungal phyllosphere communities; we observed that phyllosphere samples exposed to higher temperatures before the onset of ripening maintained more diverse fungal communities throughout development. Our analysis showed that the increase in fungal diversity among phyllopshere communities corresponds to enrichments in potential phytopathogenic fungal taxa. However, this increase in phyllosphere fungal diversity was not conserved at other growth stages when the leaves developed at higher temperatures for the whole season. The results of this study will contribute to better understanding the impact of the climate crisis on grapevine phyllosphere and carposphere fungal community composition and assembly. This will allow producers to better adapt to climate variability and to better understand the role that these communities could play on grapevine health. ### Competing Interest Statement The authors have declared no competing interest.

Conventional wastewater treatment strategies can have high financial costs which often leads to discharge of undertreated wastewater into the ecosystem. In parallel, the cultivation of willows for bioenergy can be limited due to their high water demand. Despite the potential for treatment using willow plantations, the effect of wastewater irrigation on biomass development and biofuel potential has yet to be investigated across different cultivars and sites. Here, the effect of secondary treated wastewater irrigation on wood anatomy, biomass composition and enzymatic saccharification were investigated in one poplar and thirteen willow cultivars planted at one of three sites in either Canada or Northern Ireland. There was significant anatomical and compositional variation between cultivars at all three sites, but wastewater irrigation had little impact on biomass development. Vessel and fibre cell frequencies ranged between cultivars from 129 to 178 and 4322-7058 per mm2, with average transverse areas of 838-1278 and 120-190 mu m2, respectively. Glucan and lignin content varied from 42.3 to 50.7% dry matter (DM) and 27.3-32.4% DM, respectively, whereas glucose release varied from 50 to 160 mg g-1 of glucan or 30-90 mg g-1 of DM. Glucan content and fibre cell frequency had significant positive correlations with glucose release yields, whereas average fibre cell area had an inverse correlation. These findings suggest both cell wall structure and tissue morphology could be important factors when considering biomass recalcitrance to deconstruction. Maintenance of biomass quality during irrigation provides evidence that integration of dedicated bioenergy production with environmental wastewater treatment using willow phytofiltration has potential as a promising clean biotechnology.

Organic waste decomposition can make up substantial amounts of municipal green-house emissions during decomposition. Composting has the potential to reduce these emissions as well as generate sustainable fertilizer. However, our understanding of how complex microbial communities change to drive the chemical and biological processes of composting is still limited. To investigate the microbiota associated with organic waste decomposition, initial composting feedstock (Litter), three composting windrows of 1.5 months (Young phase), 3 months (Middle phase) and 12 months (Aged phase) old, and 24-month-old mature Compost were sampled to assess physicochemical properties, plant cell wall composition and the microbial community using 16S rRNA gene amplification. A total of 2,612 Exact Sequence Variants (ESVs) included 517 annotated as putative species and 694 as genera which together captured 57.7% of the 3,133,873 sequences, with the most abundant species being Thermobifida fusca, Thermomonospora chromogena and Thermobifida bifida. Compost properties changed rapidly over time alongside the diversity of the compost community, which increased as composting progressed, and multivariate analysis indicated significant variation in community composition between each time-point. The abundance of bacteria in the feedstock is strongly correlated with the presence of organic matter and the abundance of plant cell wall components. Temperature and pH are the most strongly correlated parameters with bacterial abundance in the thermophilic and cooling phases/mature compost respectively. Differential abundance analysis revealed 810 ESVs annotated as species significantly varied in relative abundance between Litter and Young phase, 653 between the Young and Middle phases, 1182 between Middle and Aged phases and 663 between Aged phase and mature Compost. These changes indicated that structural carbohydrates and lignin degrading species were abundant at the beginning of the thermophilic phase, especially members of the Firmicute and Actinobacteria phyla. A high diversity of species capable of putative ammonification and denitrification were consistently found throughout the composting phases, whereas a limited number of nitrifying bacteria were identified and were significantly enriched within the later mesophilic composting phases. High microbial community resolution also revealed unexpected species which could be beneficial for agricultural soils enriched with mature compost or for the deployment of environmental and plant biotechnologies. Understanding the dynamics of these microbial communities could lead to improved waste management strategies and the development of input-specific composting protocols to optimize carbon and nitrogen transformation and promote a diverse and functional microflora in mature compost.

The herbicide glyphosate has several potential entry points into composting sites and its impact on composting processes has not yet been evaluated. To assess its impact on bacterial diversity and abundance as well as on community composition and dynamics, we conducted a mesocosm experiment at the Montreal Botanical Garden. Glyphosate had no effect on physicochemical property evolution during composting, while it was completely dissipated by the end of the experiment. Sampling at Days 0, 2, 28 and 112 of the process followed by 16S rRNA amplicon sequencing also found no effect of glyphosate on species richness and community composition. Differential abundance analyses revealed an increase of a few taxa in the presence of glyphosate, namely TRA3-20 (order Polyangiales), Pedosphaeraceae and BIrii41 (order Burkholderiales) after 28 days. In addition, five amplicon sequence variants (ASVs) had lower relative abundance in the glyphosate treatment compared to the control on Day 2, namely Comamonadaceae, Pseudomonas sp., Streptomyces sp., Thermoclostridium sp. and Actinomadura keratinilytica, while two ASVs were less abundant on Day 112, namely Pedomicrobium sp. and Pseudorhodoplanes sp. Most differences in abundance were measured between the different sampling points within each treatment. These results present glyphosate as a poor determinant of species recruitment during composting.

Traditional treatment of wastewaters is a burden for local governments. Using short rotation coppice willow (SRCW) as vegetal filter has several environmental and economic benefits. Here, we investigated the effect of primary wastewater irrigation on wood structure and composition of the willow cultivar Salix miyabeana ‘SX67’ following two years of growth. Compared to unirrigated plants (UI), stem sections of plants irrigated with primary wastewater (WWD) showed an unexpected decrease of hydraulic conductance (KS) associated with a decrease in vessel density but not vessel diameter. The majority (86%) of vessels had diameters range groups [20-30[, [30-40[and [40-50[µm and contributed to > 75% of theoretical KS, while the group class [50-60[µm (less than 10% of vessels) still accounted for > 20% of total KS regardless irrigation treatments. WWD significantly alters the chemical composition of wood with an increase of glucan content by 9 to 16.4% and a decrease of extractives by 35.3 to 36.4% when compared to UI or to plants irrigated with potable water (PW). The fertigation did also increase the proportion of the tension wood which highly correlated with glucan content. In the context of energetic transition and mitigation of climate change, such results are of high interest since WWD effectively permit the phytofiltration of large amounts of organic contaminated effluents without impairing SRCW physiology.

The treatment of leachate by vegetative filters composed of short-rotation willow coppice (SRWC) has been shown to be a cost-effective alternative to conventional and costly methods. However, few studies have considered the treatment capability of willow filters at a scale large enough to meet the industrial requirements of private landfill owners in North America. We report here on a field trial (0.5 ha) in which a willow plantation was irrigated with groundwater (D0) or aged leachate at two different loadings (D1 and D2, which was twice that of D1). Additionally, half of the D2-irrigated plots were amended with phosphorus (D2P). The system, which operated for 131 days, was highly efficient, causing the chemical oxygen demand concentration to drop significantly with the total removal of ammonia (seasonal average removal by a concentration of 99–100%). D2P efficacy was higher than that of D2, indicating that P increased the performance of the system. It also increased the willow biomass 2.5-fold compared to water irrigation. Leaf tissue analysis revealed significant differences in the concentrations of total nitrogen, boron, and zinc, according to the treatment applied, suggesting that the absorption capacity of willows was modified with leachate irrigation. These results indicate that the willow plantation can be effective for the treatment of landfill leachate in respect of environmental requirements.

Phytoremediation shows great promise as a plant-based alternative to conventional clean-up methods that are prohibitively expensive. As part of an integrated strategy, the selection of well-adapted plant species as well as planting and management techniques could determine the success of a long-term program. Herein, we conducted an experiment under semi-controlled conditions to screen different plants species with respect to their ability to phytoremediate Zn-contaminated soil excavated from a contaminated site following a train derailment and spillage. The effect of nitrilotriacetic acid (NTA) application on the plants and soil was also comprehensively evaluated, albeit we did not find its use relevant for field application. In less than 100 days, substantial Zn removal occurred in the soil zone proximal to the roots of all the tested plant species. Three perennial herbaceous species were tested, namely, Festuca arundinacea, Medicago sativa, and a commercial mix purposely designed for revegetation; they all showed strong capacity for phytostabilization at the root level but not for phytoextraction. The Zn content in the aboveground biomass of willows was much higher. Furthermore, the degree of growth, physiological measurements, and the Zn extraction yield indicated Salix purpurea ‘Fish Creek’ could perform better than Salix miyabeana, ‘SX67’, in situ. Therefore, we suggest implementing an S. purpurea—perennial herbaceous co-cropping strategy at this decade-long-abandoned contaminated site or at similar disrupted landscapes.

Global warming significantly increases temperatures in northern countries such as Canada. Because specific metabolic activities occur at different time during berry development and ripening, irregular temperature patterns may affect fruit biochemistry. We hypothesized that variations in GDD accumulation patterns may affect grapevine metabolism and modulate the accumulation of secondary metabolites such as phenolic compounds during berry development ripening, therefore impacting their composition at harvest. To test this hypothesis, we implemented a field experiment involving portable mini-greenhouses to locally increase the temperature of the canopy of 'L'Acadie blanc' grapevine grown in commercial vineyard in Nova Scotia, Canada during pre-veraison (Pre), post-veraison (Post), during the whole season (All) and a control. Berries were sampled at different phenological stages (EL-32, EL-36, EL-37, EL-38) and phenolic compounds profiles (24 compounds) were analyzed by LCMS/MS. Temperature treatments significantly affected phenolic compound profiles of berries but impacts differed from one phenological stage to another. At stage EL-32, the treatments Post and Control had significantly higher level of flavonoids (24.8 mg kg(-1) FW, in average) than the treatments All and Pre (2.73 mg kg(-1), FW, in average). Flavonoids were also in significantly higher concentrations in berries from the Post and Control treatments at stage EL-38 (18.4 and 10.3 mg kg(-1) FW, respectively, compared to 3.04 mg kg(-1) in All and Pre treatments, in average). Besides temperature, greenhouse treatments also altered UV radiation exposure. Yet, results showed significant metabolic shifts in phenolic compound biosynthesis from one treatment to another. They also highlighted that environmental conditions (e.g., temperature and UV exposure) during early fruit development are critical for berry composition at harvest.

Reducing the environmental impact of Canadian field crop agriculture, including the reliance on conventional synthesised fertilisers, are key societal targets for establishing long-term sustainable practices. Municipal biosolids (MSB) are an abundant, residual organic material, rich in phosphate, nitrogen and other oligo-nutrients, that could be used in conjunction with conventional fertilisers to decrease their use. Though MBS have previously been shown to be an effective fertiliser substitute for different crops, including corn and soybean, there remain key knowledge gaps concerning the impact of MBS on the resident soil bacterial communities in agro-ecosystems. We hypothesised that the MBS fertiliser amendment would not significantly impact the structure or function of the soil bacterial communities, nor contribute to the spread of human pathogenic bacteria, in corn or soybean agricultural systems. In field experiments, fertiliser regimes for both crops were amended with MBS, and compared to corn and soybean plots with standard fertiliser treatments. We repeated this across four different agricultural sites in Quebec, over 2021 and 2022. We sampled MBS-treated, and untreated soils, and identified the composition of the soil bacterial communities via 16S rRNA metabarcoding. We found no indication that the MBS fertiliser amendment altered the structure of the soil bacterial communities, but rather that the soil type and crop identities were the most significant factors in structuring the bacterial communities. Moreover, there was no evidence that the MBS-treated soils experienced a shift in functions, nor contributed potential human bacterial pathogens over the two years of our study. Our analysis indicates that not only can MBS function as substitutes for conventional, synthesised fertilisers, but that they also do not disrupt the structure, or function, of the resident soil bacterial communities in the short term. Finally, we suggest that the use of MBS in agro-ecosystems poses no greater concern to the public than existing soil bacterial communities. Highlights ![Figure][1] ### Competing Interest Statement The authors have declared no competing interest. [1]: pending:yes

Volatile compounds (VCs) in grapevine berries play an important role in wine quality; however, such compounds and vine development can be sensitive to environmental conditions. Due to this sensitivity, changes in temperature patterns due to global warming are likely to further impact grape production and berry composition. The aim of this study was to determine the possible effects of different growing-degree day accumulation patterns on berry ripening and composition at harvest. An experimental field was conducted using Vitis sp. L'Acadie blanc, in Nova Scotia, Canada. Using on-the-row mini-greenhouses, moderate temperature increase and reduced ultraviolet (UV) exposure were triggered in grapevines during pre-veraison (inflorescence to the beginning of berry softening), post-veraison (berry softening to full maturity), and whole season (inflorescence to full maturity), while controls were left without treatment. Free and bound VCs were extracted from berries sampled at three different phenological stages between veraison and maturity before analysis by gas chromatography–mass spectrometry (GC-MS). Berries from grapevines exposed to higher temperatures during early berry development (pre-veraison and whole) accumulated significantly higher concentrations of benzene derivatives 2-phenylethanol and benzyl alcohol at harvest, but lower concentrations of hydroxy-methoxy-substituted volatile phenols, terpenes, and C 13 -norisoprenoids than the control berries. These results illustrate the importance of different environmental interactions in berry composition and suggest that temperature could potentially modulate phenylpropanoid and mevalonate metabolism in developing berries. This study provides insights into the relationships between abiotic conditions and secondary metabolism in grapevine and highlights the significance of early developmental stages on berry quality at harvest.

Phytoextraction of trace elements (TE) using woody species is an economically challenging soil remediation approach because of the long time needed. Yet, some trees contain alkaloids that can be exploited along structural components to enhance biomass value. As alkaloids are thought to be involved in plant defence mechanisms, we hypothesized that potentially hostile phytoremediation conditions could increase their level. Camptothecin in Camptotheca acuminata and 1-deoxynojirimycin in Morus alba were measured from trees grown in a field in presence of Cu, Pb and Zn all together, and from M. alba grown in a greenhouse in presence of Cd or other abiotic stressors (NaCl and bending). The trees did not extract TE in the field, but M. alba stems accumulated Cd in the greenhouse experiment, with no consequence on stomatal conductance and leaves pigments concentration. Camptothecin and 1-deoxynojirimycin concentrations were preserved under all experimental conditions, as was biomass yield, and phenolics were slightly increased in M. alba exposed to TE. This study provides evidence that valuable and persistent alkaloids and phenolics can be extracted from trees facing phytoremediation-associated stresses, without a negative impact on their quantity and on biomass yield. Such products could generate a sustainable stream of revenues during phytoremediation. NOVELTY STATEMENT There is scarce data on tree alkaloid content and scarcer data on how it is affected by exposure to trace elements in a phytoremediation context. We provide evidence that the content of two specific alkaloids is not altered in Morus alba and Camptotheca acuminata exposed to moderate to elevated levels of contaminating trace elements. The manuscript introduces the use of M. alba for phytoremediation in the Americas and is the first to propose the use of C. acuminata on trace element contaminated sites to produce camptothecin, a valuable anticancer alkaloid.

Conventional wastewater treatment relies on a complex microbiota; however, much of this community is still to be characterized. To better understand the origin, dynamics and fate of bacteria within a wastewater treatment plant: untreated primary wastewater, activated sludge and post-treatment effluent were characterized. From 3163 exact sequence variants (ESVs), 860 were annotated to species-level. In primary wastewater, 28% of ESVs were putative bacterial species previously associated with humans, 14% with animals and 5% as common to the environment. Differential abundance analysis revealed significant relative reductions in ESVs from potentially human-associated species from primary wastewater to activated sludge, and significant increases in ESVs from species associated with nutrient cycling. Between primary wastewater and effluent, 51% of ESVs from human-associated species did not significantly differ, and species such as Bacteroides massiliensis and Bacteroides dorei increased. These findings illustrate that activated sludge increased extracellular protease and urease-producing species, ammonia and nitrite oxidizers, denitrifiers and specific phosphorus accumulators. Although many human-associated species declined, some persisted in effluent, including strains of potential health or environmental concern. Species-level microbial assessment may be useful for understanding variation in wastewater treatment efficiency as well as for monitoring the release of microbes into surface water and the wider ecosystem.

Willow (Salix) biomass production has been expanding dramatically in recent years with the development of phytoremediation and wastewater treatment projects and plans to build bio-refineries are increasing the future options for valorizing this biomass. In this context, winter storage of biomass after harvesting is unavoidable, due to limited shelter capacity. Questions about the impact of outdoor storage during winter and stem age at harvest time led to the establishment of an experiment on the site of Ramo®, a biomass-based products producer. Two- and three-year-old Salix miyabeana ‘SX67′ stems were chipped and piled after leaf fall in November 2018. Temperature was measured during the experiment, while physicochemical parameters and biomass composition were analyzed at the beginning and the end. The experiment showed that stem age influenced the initial biomass composition, with the two-year-old stems containing more extractives and the three-year-old stems containing more structural sugars. Heat production varied with stem age, which was reflected in the final biomass composition. A loss of extractives and an increase in lignin was measured in both stem types, while an increase in glucan, xylan and mannan was also measured in the two-year-old chips. This new information complements existing data on mass loss during wood chip storage and provides essential knowledge for future decision-making related to the development of lignocellulose value chains from bioenergy crops.