International audience | There is growing scientific and societal consciousness that the environmental risks and impacts of plant protection products (PPPs) cannot be properly assessed without considering ecosystem services. However, the science on this issue remains incomplete and fragmented, as recently illustrated in a collective scientific assessment that pointed out the limited knowledge on the risks and impacts of PPPs on soil ecosystem services, which are clearly overlooked. Beside soil ecosystem services, certain key players involved in these services are largely overlooked in the scientific literature on the risks and impacts of PPPs, namely soil microbial photosynthetic communities. Here, we followed the principles of evidence-based logic chain approaches to show the importance of considering these microorganisms when studying the impacts of PPPs on certain services provided by soil ecosystems, with a focus on regulating and maintenance services that play a role in the regulation of baseline flows and extreme events. Terrestrial microalgae and cyanobacteria are ubiquitous photosynthetic microorganisms that, together with other soil micro- and macro-organisms, play key roles in the ecosystem functions that underpin these ecosystem services. There is an extensive literature on the ecotoxicological effects of PPPs on different organisms including soil microorganisms, but studies concerning soil microbial photosynthetic communities are very scarce. However, there is scientific evidence that herbicides can have both direct and indirect impacts on these microbial photosynthetic communities. Given that they play key functional roles, we argue that soil microbial photosynthetic communities warrant greater attention in efforts to assess the environmental risks and impacts of PPPs and, ultimately, help preserve or restore the regulating and maintenance services provided by soil ecosystems.

International audience | Plastic has been largely detected in estuarine environments and represents major concern towards aquatic living organisms. The present study evaluates the impact of microplastics (MPs) and nanoplastics (NPs) under realistic exposure conditions. Scrobicularia plana individuals were exposed to low concentrations (0.008, 10, and 100 µg L−1) of environmental MPs and NPs as well as to standard PS NPs, as a comparison condition. The aim of this study was to understand the ecotoxicological effects of environmental plastic particles on S. plana gills and digestive glands but also to compare the effects of plastic polymers size in order to highlight if the size could induce different toxicity profiles within this model organism, at different levels of biological organization. Results showed a differential induction of detoxification enzymes (CAT, GST), immunity (AcP), DNA damage processes as well as a differential effect on behavior and condition index of animals depending upon the type of plastic, the size, the concentration tested, and the type of organ. This study underlines the necessity of testing (i) plastics collected from the environment as compared to standard ones and (ii) the effect of size using plastics coming from the same batch of macrosized plastics. This study concludes on the future need directions that plastic-based studies must take in order to be able to generate a large quantity of relevant data that could be used for future regulatory needs on the use of plastic.

International audience | There is growing scientific and societal consciousness that the environmental risks and impacts of plant protection products (PPPs) cannot be properly assessed without considering ecosystem services. However, the science on this issue remains incomplete and fragmented, as recently illustrated in a collective scientific assessment that pointed out the limited knowledge on the risks and impacts of PPPs on soil ecosystem services, which are clearly overlooked. Beside soil ecosystem services, certain key players involved in these services are largely overlooked in the scientific literature on the risks and impacts of PPPs, namely soil microbial photosynthetic communities. Here, we followed the principles of evidence-based logic chain approaches to show the importance of considering these microorganisms when studying the impacts of PPPs on certain services provided by soil ecosystems, with a focus on regulating and maintenance services that play a role in the regulation of baseline flows and extreme events. Terrestrial microalgae and cyanobacteria are ubiquitous photosynthetic microorganisms that, together with other soil micro- and macro-organisms, play key roles in the ecosystem functions that underpin these ecosystem services. There is an extensive literature on the ecotoxicological effects of PPPs on different organisms including soil microorganisms, but studies concerning soil microbial photosynthetic communities are very scarce. However, there is scientific evidence that herbicides can have both direct and indirect impacts on these microbial photosynthetic communities. Given that they play key functional roles, we argue that soil microbial photosynthetic communities warrant greater attention in efforts to assess the environmental risks and impacts of PPPs and, ultimately, help preserve or restore the regulating and maintenance services provided by soil ecosystems.

International audience | The silverleaf whitefly Bemisia tabaci (Gennadius, 1889) (Homoptera: Aleyrodidae) is a serious invasive herbivorous insect pest worldwide. The excessive use of pesticides has progressively selected B. tabaci specimens, reducing the effectiveness of the treatments, and ultimately ending in the selection of pesticide-resistant strains. The management of this crop pest has thus become challenging owing to the level of resistance to all major classes of recommended insecticides. Here, we used in silico techniques for detecting sequence polymorphisms in ace1 gene from naturally occurring B. tabaci variants, and monitor the presence and frequency of the detected putative mutations from 30 populations of the silverleaf whitefly from Egypt and Pakistan. We found several point mutations in ace1-type acetylcholinesterase (ace1) in the studied B. tabaci variants naturally occurring in the field. By comparing ace1 sequence data from an organophosphate-susceptible and an organophosphate-resistant strains of B. tabaci to ace1 sequence data retrieved from GenBank for that species and to nucleotide polymorphisms from other arthropods, we identified novel mutations that could potentially influence insecticide resistance. Homology modeling and molecular docking analyses were performed to determine if the mutation-induced changes in form 1 acetylcholinesterase (AChE1) structure could confer resistance to carbamate and organophosphate insecticides. Mutations had small effects on binding energy (Delta G(b)) interactions between mutant AChE1 and insecticides; they altered the conformation of the peripheral anionic site of AChE1, and modified the enzyme surface, and these changes have potential effects on the target-site sensitivity. Altogether, the results from this study provide information on genic variants of B. tabaci ace1 for future monitoring insecticide resistance development and report a potential case of environmentally driven gene variations.

In comparison with northern countries, limited data are available on the occurrence and potential toxicity of cyanobacterial blooms in lakes and ponds in sub-Saharan countries. With the aim of enhancing our knowledge on cyanobacteria and their toxins in Africa, we performed a 17-month monitoring of a freshwater ecosystem, Lagoon Aghien (Ivory Coast), which is used for multiple practices by riverine populations and for drinking water production in Abidjan city. The richness and diversity of the cyanobacterial community were high and displayed few variations during the entire survey. The monthly average abundances ranged from 4.1 × 10 4 to 1.8 × 10 5 cell mL −1 , with higher abundances recorded during the dry seasons. Among the five cyanotoxin families analyzed (anatoxin-a, cylindrospermopsin, homoanatoxin, microcystins, saxitoxin), only microcystins (MC) were detected with concentrations ranging from 0 to 0.364 μg L −1 in phytoplankton cells, from 32 to 1092 μg fresh weight (FW) kg −1 in fish intestines, and from 33 to 383 μg FW kg −1 in fish livers. Even if the MC concentrations in water and fish are low, usually below the thresholds defined in WHO guidelines, these data raise the issue of the relevance of these WHO guidelines for sub-Saharan Africa, where local populations are exposed throughout the year to these toxins in multiple ways.

International audience

International audience | The proliferation of wireless and other telecommunications equipment brought about by technological advances in the communication industry has substantially increased the radiofrequency radiation levels in the environment. The emphasis is, therefore, placed on investigating the potential impacts of radiofrequency radiation on biota. In this work, the impact of 2850 MHz electromagnetic field radiation (EMF-r) on early development, photosynthetic pigments, and the metabolic profile of two Brassica oleracea L. cultivars (red and green cabbage) was studied. On a daily basis for seven days, seedlings were exposed to homogeneous EMF-r for one, two, and four hours, and observations were carried out at 0-h, 1-h, and 24-h following the final dose. Irrespective of the duration of harvest, exposure to EMF-r resulted in a dose-dependent reduction in both root (from 6.3 cm to 4.0 cm in red; 6.1 cm to 3.8 cm in green) and shoot lengths (from 5.3 cm to 3.1 cm in red; 5.1 cm to 3.1 cm in green), as well as a decrease in biomass (from 2.9 mg to similar to 1.1 mg in red; 2.5 to 0.9 mg in green) of the seedlings when compared to control samples. Likewise, the chlorophyll (from 6.09 to similar to 4.94 mg g(-1) d.wt in red; 7.37 to 6.05 mg g(-1) d.wt. in green) and carotenoid (from 1.49 to 1.19 mg g(-1) d.wt. in red; 1.14 to 0.51 mg g(-1) d.wt. in green) contents of both cultivars decreased significantly when compared to the control. Additionally, the contents of phenolic (28.99-45.52 mg GAE g(-1) in red; 25.49-33.76 mg GAE g(-1) in green), flavonoid (21.7-31.8 mg QE g(-1) in red; 12.1-19.0 mg QE g(-1) in green), and anthocyanin (28.8-43.6 mg per 100 g d.wt. in red; 1.1-2.6 mg per 100 g d.wt. in green) in both red and green cabbage increased with exposure duration. EMF-r produced oxidative stress in the exposed samples of both cabbage cultivars, as demonstrated by dose-dependent increases in the total antioxidant activity (1.33-2.58 mM AAE in red; 1.29-2.22 mM AAE in green), DPPH activity (12.96-78.33% in red; 9.62-67.73% in green), H2O2 content (20.0-77.15 nM g(-1) f.wt. in red; 14.28-64.29 nM g(-1) f.wt. in green), and MDA content (0.20-0.61 nM g(-1) f.wt. in red; 0.18-0.51 nM g(-1) f.wt. in green) compared to their control counterparts. The activity of antioxidant enzymes, i.e., superoxide dismutases (3.83-8.10 EU mg(-1) protein in red; 4.19-7.35 EU mg(-1) protein in green), catalases (1.81-7.44 EU mg(-1) protein in red; 1.04-6.24 EU mg(-1) protein in green), and guaiacol peroxidases (14.37-47.85 EU mg(-1) protein in red; 12.30-42.79 EU mg(-1) protein in green), increased significantly compared to their control counterparts. The number of polyphenols in unexposed and EMF-r exposed samples of red cabbage was significantly different. The study concludes that exposure to 2850 MHz EMF-r affects the early development of cabbage seedlings, modifies their photosynthetic pigments, alters polyphenol content, and impairs their oxidative metabolism.

International audience | Contamination of sunflower seeds with soil Cd is an important issue for food and feed because this species strongly accumulates this metal. The present work reports that seeds from three sunflower varieties (ES Biba, Extrasol, Vellox) cultivated in the field in a calcareous agricultural soil having a moderately high Cd content (1 mg Cd/kg) had Cd contents of 0.84, 0.88 and 0.76 mg Cd/kg, respectively, all exceeding the regulation limit of 0.5 mg Cd/kg seeds for human food. On average, for the three varieties, washing seeds did not affect their total Cd contents but slightly increased the Cd in the kernels at the expense of that in hulls. Despite the Cd content of the whole seeds not differing between the varieties, the Cd fraction in the edible kernel differed significantly between varieties from 78 to 87% of the total seed Cd. The results of this study suggest that (i) the size of the kernel, relative to that of the hull, may affect the dilution of Cd in kernel tissues and (ii) there might be genetic variability for the capacity of transfer of Cd from the hull to the kernel. This opens the perspective to increase food safety by selecting sunflower genotypes that retain more Cd into the hull and transfer less of it to the edible kernel.

International audience