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In spite of global actions, biodiversity is declining at an alarming rate. Despite the need for objectively comparable monetary standards to include biodiversity arguments in policymaking, research on the relationship between species diversity and its valuation from a societal perspective is still scarce. In this paper, a methodological framework for the valuation of natural predators based on their ecological role in the agroecosystem is introduced. The framework integrates a dynamic ecological model simulating interactions between species with an economic model, thereby quantifying the effect of reduced numbers of natural predators on the net farm income. The model attributes an objective monetary value to increased species diversity through the changes in the provisioning of a marketable good. Results indicate that the loss of three predators could decrease net farm income with 88.86 €ha-1 to 2186.5 €ha-1. For the pear production sector in Flanders in 2011, this constitutes to an indirect use value of 0,68 million € for one predator and 16.63 million € for the presence of three predators. The aim is to provide a justification for the argument for biodiversity conservation, based on the ecological function of species, through the delivery of comparable monetary standards. The research was made possible with the financial aid from a BOF grant of the Centre for Environmental Sciences (CMK, Hasselt University). Nele Witters is funded by Research Foundation- Flanders (FWO). The authors would like to thank Ellen Elias from Symbio for providing relevant data and insights into the complex interplay between pest insects, natural predators and human impacts from fertilizers and pesticide use.

ACTI; International audience; The European INTENSE project is responding to three “Great Challenges”: global food security, use of renewable raw materials and production of energy from biomass. Its contributes to reconvert poor, abandoned and polluted lands, e.g. grassland, set aside land, brownfields, and other marginal lands, into high, sustainable crop production. INTENSE sites are located throughout Europe from Spain in the south up to Norway in the north. Regarding precision agriculture, modeling tools and soil amendments, field plots are assessed using unmanned aerial vehicles and data crossed with those from crop production and soil microbial communities. This provides information on field heterogeneity to adapt soil management, seeding, fertilizing, and fungicide and herbicide application, allowing site-specific farming. At the Martlhof farm, Germany, increase in photosynthetic activity of barley was observed after incorporation of digested pig manure (solid fraction alone and with biochar) and compost although N uptake was similar. At Buendia and Casasana, Spain, barley plots with mineral N combined with compost pellets and biochar showed increased GNDVI (i.e. (NIR – green)/(NIR + green). Field data and image spectroscopy evidenced differences across plots, cultivars, plant performance and health. At Polish sites, compost combined with mineral N increased barley and maize yields. Suitable production systems are developed and implemented for land amelioration in complex degradation situations. At Martlhof, chestnut wood chips are pyrolysed to produce and use biochar. Extensive livestock farming is transformed to ecological intensive farming including livestock with monogastric animals, intercropping (Fabaceae), agroforestry, terraforming, and increased biodiversity (landscape ecology). Soil nutrients and biological functionality (FDA hydrolysis, community-level physiological profiling, and microbial DNA extractions) are analyzed at the beginning and after each growing season, showing high nutrient turnover, and increase in soil N and P contents. Organic amendments more influence overall microbial activity than functional diversity. Overall, the more organic matter, the higher the microbial activity. At French sites, long-term phytomanagement of contaminated soils with high yielding crops and short rotation coppices, combined with soil amendments, improved soil fertility, C sequestration, can stimulate microbial activity, and limited pollutant linkages. Weed control, reduced invasive vegetation, pest control, effect of soil mycorrhizae on nutrient cycling, and shelter belts are investigated. At Spanish sites, farming systems can be adapted by limiting wind erosion and water runoff, shaping stony fields, tree planting, soil amendment, winter crops and intercropping. At the farm level, environmental education, direct marketing, and (bio)energy production can add values

Air pollution, containing fossil fuel-related volatile organic compounds (VOCs), constitutes a major problem in most urban areas. Worldwide, more people die from exposure to air pollution than from malaria and HIV infection together. Many years of research show that plant–microbe interactions can be exploited to significantly enhance phytoremediation of contaminated environments. Microorganisms living on plant leaves constitute promising candidates to detoxify harmful VOCs and promote plant growth. Hedera helix, an evergreen plant known for its hardiness and climbing ability, proves to be an excellent host species in the context of phytoremediation of air pollution. We employed 16S rRNA gene amplicon-based metagenomics to characterize the taxonomic structure of phyllospheric microbial communities associated with H. helix. Further, we investigated 33 bacterial isolates from 8 different genera using culture-dependent approaches and whole genome sequencing. Our results indicate that the relative composition of the H. helix phyllobiome is similar to that of the model plant Arabidopsis thaliana. The presence of pathways related to detoxification of fossil fuel-related VOCs could be confirmed by genome-level analyses of bacterial isolates showing a high in vitro capacity to metabolize selected VOCs and promote plant growth. We provide an integrated description of the H. helix phyllobiome, including the identification of interesting bacteria with significant potential as inoculants in phytoremediation approaches. Het Fonds voor Wetenschappelijk Onderzoek – Vlaanderen (FWO)

This work was supported by the Research Foundation Flanders (FWO) by project funding for CL [G0D3414N] and MH [G0B6716] and a postdoctoral grant for EK. An additional IWT scholarship was obtained for MG.

Ecotrons are large scale research infrastructures offering a compromise between high level of control and recording ecosystem processes at a relevant spatial scale. Since ecosystem functioning is strongly influenced by climatic variables, simulating weather conditions and stochasticity accurately is crucial to ensure that results are not disconnected from reality. Here, we describe how to use input from an ICOS ecosystem tower to simulate in real time weather conditions in an ecotron facility. The ecotrons are filled with lysimeters containing dry heathland ecosystem. The parameters are controlled are not only atmospheric (temperature, relative humidity, precipitation, CO2 concentration) but also belowground (temperature and water tension). We illustrate the accuracy at which our ecotron-ICOS tower design can reproduce these parameters. We also describe how we plan to alter the ICOS input for two climate-change experiments.

Cadmium (Cd) pollution renders many soils across the world unsuited or unsafe for food- or feed-orientated agriculture. The main mechanism of Cd phytotoxicity is the induction of oxidative stress, amongst others through the depletion of glutathione. Oxidative stress can damage lipids, proteins, and nucleic acids, leading to growth inhibition or even cell death. The plant cell has a variety of tools to defend itself against Cd stress. First and foremost, cell walls might prevent Cd from entering and damaging the protoplast. Both the primary and secondary cell wall have an array of defensive mechanisms that can be adapted to cope with Cd. Pectin, which contains most of the negative charges within the primary cell wall, can sequester Cd very effectively. In the secondary cell wall, lignification can serve to immobilize Cd and create a tougher barrier for entry. Changes in cell wall composition are, however, dependent on nutrients and conversely might affect their uptake. Additionally, the role of ascorbate (AsA) as most important apoplastic antioxidant is of considerable interest, due to the fact that oxidative stress is a major mechanism underlying Cd toxicity, and that AsA biosynthesis shares several links with cell wall construction. In this review, modifications of the plant cell wall in response to Cd exposure are discussed. Focus lies on pectin in the primary cell wall, lignification in the secondary cell wall and the importance of AsA in the apoplast. Regarding lignification, we attempt to answer the question whether increased lignification is merely a consequence of Cd toxicity, or rather an elicited defense response. We propose a model for lignification as defense response, with a central role for hydrogen peroxide as substrate and signaling molecule. This work was supported by the Research Foundation Flanders (FWO) by project funding for CL [G0D3414N] and MH [G0B6716] and a postdoctoral grant for EK. An additional IWT scholarship was obtained for MG.

The basidiomycete Suillus luteus is an important member of the ectomycorrhizal community that thrives in heavy metal polluted soils covered with pioneer pine forests. This study aimed to identify potential heavy metal chelators in S. luteus. Two metallothionein (MT) coding genes, SlMTa and SlMTb, were identified. When heterologously expressed in yeast, both SlMTa and SlMTb can rescue the Cu sensitive mutant from Cu toxicity. In S. luteus, transcription of both SlMTa and SlMTb is induced by Cu but not Cd or Zn. Several putative Cu-sensing and metal-response elements are present in the promoter sequences. These results indicate that SlMTa and SlMTb function as Cu-thioneins. Homologs of the S. luteus MTs are present in 49 species belonging to 10 different orders of the subphylum Agaricomycotina and are remarkably conserved. The length of the proteins, number and distribution of cysteine residues indicate a novel family of fungal MTs. The ubiquitous and highly conserved features of these MTs suggest that they are important for basic cellular functions in species in the subphylum Agaricomycotina. This work was financially supported by the Research Foundation Flanders (FWO-Vlaanderen) and the Hasselt University Methusalem project 08M03VGRJ.

In accordance with realistic application approaches, a short-term 1-factorial experiment was set up to investigate the phytotoxic impact of pre-emergent application of the chloroacetamide herbicide metazachlor on Brassica napus. In addition to morphological parameters, the underlying processes that ultimately determine the extent of herbicide-induced phytotoxicity (i.e., herbicide metabolization and cellular antioxidant defense) were examined. The present study demonstrated that metazachlor provoked fasciation of the leaves closely after emergence, which might be linked to its mode of action whereby cell division is impaired through the inhibition of very long chain fatty acid synthesis. The increased activities of antioxidative enzymes and metabolites in leaf tissue indicated the presence of reactive oxygen species under the influence of metazachlor. This resulted in oxidative damage in the form of membrane lipid peroxidation. Simultaneously, the increased activity of glutathione S-transferase and the shift in glutathione redox state suggested activation of the detoxification metabolism. This occurred, however, at the expense of growth, with a temporary reduction in plant height and weight after application. The results indicated that metazachlor disappeared within 3 mo to 4 mo after application, which resulted in the recovery of the crop. In conclusion, metazachlor induces phytotoxicity in the short term, either directly through its mode of action or indirectly through the induction of oxidative stress, which resulted in a temporary reduction in growth. Environ Toxicol Chem 2017;36:59-70. (c) 2016 SETAC We thank A. Wijgaerts and C. Put for their technical assistance in the microcosm experiment. The present study was supported by a PhD grant from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen, to H. Vercampt).

Cadmium (Cd) exposure can disturb the homeostasis of essential elements. In Arabidopsis thaliana, Cd induces a squamosa promoter binding protein-like 7 (SPL7)-dependent Cu deficiency response. We investigated how Cd induces a Cu deficiency response. The Cu deficiency response consists of the active SPL7 transcription factor binding to GTAC motifs in promoters of among others several Cu transporters, a Cu chaperone, and cupro-miRNAs to regulate Cu homeostasis. We demonstrated that the addition of supplemental Cu to Cd-exposed A.thaliana plants diminished the Cu deficiency response in roots, while it even disappeared in leaves. Exposure of plants to Cd in combination with extra Cu reduced Cd levels in both roots and leaves resulting in an improved cellular oxidative state. Furthermore, we demonstrated a role for phytochelatins (PCs) in the Cd-induced Cu deficiency response, because it was reduced in roots of cad1-3 mutant plants exposed to Cd. In conclusion, a working mechanism is provided in which it is suggested that Cd increases PC levels that can complex both Cd and Cu. This results in cellular Cu deficiency and subsequently the activation of SPL7 and hence the induction of the Cu deficiency response. Summary statement We demonstrated that addition of supplemental Cu to Cd-exposed Arabidopsis thaliana plants diminished the SPL7-dependent Cu deficiency response in roots, while it even disappeared in leaves. Moreover, in roots of phytochelatin (PC-) deficient cad1-3 mutants, this Cu deficiency response was reduced. Therefore, a working mechanism is provided in which it is suggested that Cd increases PC levels that can complex both Cd and Cu. This results in cellular Cu deficiency and subsequently the activation of SPL7 and hence the induction of the Cu deficiency response. This work was supported by Hasselt University by a PhD grant for Heidi Gielen and through the Methusalem project [08M03VGRJ].

Air pollution, containing fossil fuel-related volatile organic compounds (VOCs), constitutes a major problem in most urban areas. According to recent data, more people die from exposure to air pollution than from malaria and HIV infection together. Many years of research show that plant–microbe interactions can be exploited to significantly enhance phytoremediation of contaminated environments. Microorganisms living on plant leaves constitute promising candidates to detoxify harmful VOCs and promote plant growth. Hedera helix, an evergreen plant known for its hardiness and climbing ability, proves to be an excellent host species in the context of phytoremediation of air pollution. We employed 16S rRNA gene amplicon-based metagenomics and real-time PCR to characterize the taxonomic structure of phyllospheric microbial communities associated with H. helix, and compared the communities present at polluted high-traffic locations with non-polluted sites. Further, we investigated bacterial isolates using culture-dependent approaches and sequenced the genomes of promising bacteria with regard to phytoremediation applications. Our results indicate that Actinobacteria, Firmicutes and Betaproteobacteria are more abundantly present on H. helix leaves in a polluted environment. Moreover, the relative composition of the H. helix phyllobiome appears to be similar to that of the model plant Arabidopsis thaliana. We further show that air pollution increases the prevalence of bacterial functional traits affiliated to plant growth and detoxification of fossil fuel-related VOCs. The presence of relevant pathways could be confirmed by genome-level analyses of bacterial isolates showing a high in vitro capacity to metabolize selected VOCs and promote plant growth. In conclusion, an integrated description of the H. helix phyllobiome is presented, including the identification of interesting bacteria with significant potential as inoculants in phytoremediation approaches. This work is supported by the Hasselt University Methusalem project 08M03VGRJ