Several studies have explored the utilization of soil microorganisms, to address the environmental issues associated with glyphosate use and enhance crop yields. In our investigation, screening on Agar plate and broth medium  Luria Bertani was carried out after isolating bacterial strains from rhizospheric agricultural soil in Mascara,  Algeria, to biodegrade glyphosate, following that by testing the Plant Growth-Promoting Rhizobacteria and evaluate the effects of glyphosate on these proprieties. Our findings indicate that five bacterial strains exhibited growth in the presence of glyphosate concentrations up to 25 mg/ml, beyond this concentration the strains have developed tolerance. Following a partial examination of the 16S rRNA sequences, the bacterial strains were identified as belonging to the genus of Enterobacter. After 10 days of incubation with the glyphosate, Phosphate solubilization decreased in broth and agar Pikovskaya medium and the bacterial strains synthetized less of indole-3-acetic acid compared to the control, indicating the impact of glyphosate on these outcomes, high concentration of glyphosate inhibited nitrogen fixation, and various doses of glyphosate were found to restrict the growth of biofilms in these strains. The results of HPLC examination of secondary metabolites revealed that the primary degradation products of glyphosate in all strains were Sarcosine and Glycine. So, it seemed that the strain could both biodegrade glyphosate and use it for growth ,while also possessing rhizobacteria properties that promote plant development, enabling the use of the strains in the bioremediation of glyphosate-contaminated soils.

The introduction of glyphosate-tolerant (GT) crops is expected to mitigate the environmental contamination by herbicides because glyphosate is less persistent and toxic than the herbicides used on non-GT crops. Here, we compared the environmental balances of herbicide applications for both crop types in three French field trials. The dynamic of herbicides and their metabolites in soil, groundwater and air was simulated with PRZM model and compared to field measurements. The associated impacts were aggregated with toxicity potentials calculated with the fate and exposure model USES for several environmental endpoints. The impacts of GT systems were lower than those of non-GT systems, but the accumulation in soils of one glyphosate metabolite (aminomethylphosphonic acid) questions the sustainability of GT systems. The magnitude of the impacts depends on the rates and frequency of glyphosate application being highest for GT maize monoculture and lowest for combination of GT oilseed rape and non-GT sugarbeet crops. The impacts of herbicide applications on glyphosate-tolerant crops could be higher than expected due to the accumulation of a metabolite of glyphosate in soils.

International audience | Prolonged exposure to low levels of dietary contaminants is a context in modern life that could alter organ physiology gradually. Here, we aimed to investigate the impact of continuous exposure to acceptable daily intake (ADI) and non-observable adverse effect level (NOAEL) of glyphosate from gestation to adulthood using C57BL/6J mice and incorporating these levels into their food pellets. From adulthood, we analyzed neurophysiological and neuro-glia cellular adaptations in male and female animals. Using ex-vivo hippocampal slice electrophysiology, we found a reduced efficacy of Schaffer collateral-to-CA1 excitatory synapses in glyphosate-exposed dietary conditions, with ADI and NOAEL dose-dependent effects. Short-term facilitation of excitatory synaptic transmission was specifically increased in NOAEL conditions, with a predominant influence in males, suggesting a reduced probability of neurotransmitter release. Long-term synaptic potentiation (LTP) was decreased in NOAEL-exposed mice. Next, we explore whether these neurophysiological modifications are associated with neuro-glia changes in the somatosensory cortex and hippocampus. High-resolution confocal microscopy analyses unveil a dose-dependent increased density of excitatory Vglut1+ Homer1+ synapses. Microglial Iba1+ cells displayed a shortening of their ramifications, a sign of cellular reactivity that was more pronounced in males at NOAEL levels. The morphology of GFAP+ astrocytes was generally not modified. Finally, we asked whether mouse-specific cross-correlations exist among all data sets generated. This examination included the novel object recognition (NOR) test performed before ex vivo functional and immunohistochemical examinations. We report a negative linear regression between the number of synapses and NOR or LTP maintenance when plotting ADI and NOAEL datasets. These results outline synaptic and microglial cell adaptations resulting from prenatal and continuous dietary low levels of glyphosate, discernible in, but not limited to, adult males exposed to the NOAEL. We discuss the significance of these findings to real-world consumer situations and long-term brain resilience.

International audience | Pesticides are often found at high concentrations in small ponds near agricultural field where amphibians are used to live and reproduce. Even if there are many studies on the impacts of phytopharmaceutical active ingredients in amphibian toxicology, only a few are interested in the earlier steps of their life cycle. While their populations are highly threatened with extinction. The aim of this work is to characterize the effects of glyphosate and its commercial formulation Roundup® GT Max on the Xenopus laevis oocyte maturation which is an essential preparation for the laying and the fertilization. Glyphosate is an extensively used herbicide, not only known for its effectiveness but also for its indirect impacts on non-target organisms. Our results showed that exposures to both forms of glyphosate delayed this hormone-dependent process and were responsible for spontaneous maturation. Severe and particular morphogenesis abnormalities of the meiotic spindle were also observed. The MAPK pathway and the MPF did not seem to be affected by exposures. The xenopus oocyte is particularly affected by the exposures and appears as a relevant model for assessing the effects of environmental contamination.

International audience | Pesticides are often found at high concentrations in small ponds near agricultural field where amphibians are used to live and reproduce. Even if there are many studies on the impacts of phytopharmaceutical active ingredients in amphibian toxicology, only a few are interested in the earlier steps of their life cycle. While their populations are highly threatened with extinction. The aim of this work is to characterize the effects of glyphosate and its commercial formulation Roundup® GT Max on the Xenopus laevis oocyte maturation which is an essential preparation for the laying and the fertilization. Glyphosate is an extensively used herbicide, not only known for its effectiveness but also for its indirect impacts on non-target organisms. Our results showed that exposures to both forms of glyphosate delayed this hormone-dependent process and were responsible for spontaneous maturation. Severe and particular morphogenesis abnormalities of the meiotic spindle were also observed. The MAPK pathway and the MPF did not seem to be affected by exposures. The xenopus oocyte is particularly affected by the exposures and appears as a relevant model for assessing the effects of environmental contamination.

International audience | Abstract France is the first pesticide-consuming country in Europe. Glyphosate is the most used pesticide worldwide and glyphosate is detected in the general population of industrialized countries, with higher levels found in farmers and children. Little data was available concerning exposure in France. Our objective was to determine glyphosate levels in the French general population and to search for an association with seasons, biological features, lifestyle status, dietary habits, and occupational exposure. This study includes 6848 participants recruited between 2018 and 2020. Associated data include age, gender, location, employment status, and dietary information. Glyphosate was quantified by a single laboratory in first-void urine samples using ELISA. Our results support a general contamination of the French population, with glyphosate quantifiable in 99.8% of urine samples with a mean of 1.19 ng/ml + / − 0.84 after adjustment to body mass index (BMI). We confirm higher glyphosate levels in men and children. Our results support glyphosate contamination through food and water intake, as lower glyphosate levels are associated with dominant organic food intake and filtered water. Higher occupational exposure is confirmed in farmers and farmers working in wine-growing environment. Thus, our present results show a general contamination of the French population with glyphosate, and further contribute to the description of a widespread contamination in industrialized countries.

International audience | Abstract France is the first pesticide-consuming country in Europe. Glyphosate is the most used pesticide worldwide and glyphosate is detected in the general population of industrialized countries, with higher levels found in farmers and children. Little data was available concerning exposure in France. Our objective was to determine glyphosate levels in the French general population and to search for an association with seasons, biological features, lifestyle status, dietary habits, and occupational exposure. This study includes 6848 participants recruited between 2018 and 2020. Associated data include age, gender, location, employment status, and dietary information. Glyphosate was quantified by a single laboratory in first-void urine samples using ELISA. Our results support a general contamination of the French population, with glyphosate quantifiable in 99.8% of urine samples with a mean of 1.19 ng/ml + / − 0.84 after adjustment to body mass index (BMI). We confirm higher glyphosate levels in men and children. Our results support glyphosate contamination through food and water intake, as lower glyphosate levels are associated with dominant organic food intake and filtered water. Higher occupational exposure is confirmed in farmers and farmers working in wine-growing environment. Thus, our present results show a general contamination of the French population with glyphosate, and further contribute to the description of a widespread contamination in industrialized countries.

The potential environmental risk of glyphosate has promoted the need for decontamination of glyphosate-polluted water bodies. These treatments should be accompanied by studies of the recovery potential of aquatic communities and ecosystems. We evaluated the potential of freshwater periphyton to recover from glyphosate exposure using microcosms under laboratory conditions. Periphyton developed on artificial substrates was exposed to 0.4 or 4 mg l⁻¹ monoisopropylamine salt of glyphosate (IPA) for 7 days, followed by translocation to herbicide-free water. We sampled the community 1, 2 and 3 weeks after the transfer. Dry weight, ash-free dry weight, chlorophyll a, and periphyton abundances were analysed. The periphyton impacted with the lowest IPA concentration recovered most of the structural parameters within 7 days in clean water, but the taxonomic structure did not entirely recover towards the control structure. Periphyton exposed to 4 mg IPA l⁻¹ could not recover during 21 days in herbicide-free water, reaching values almost four times higher in % of dead diatoms and four times lower in ash-free dry weight concerning the control at the end of the study. Results suggest a long-lasting effect of the herbicide due to the persistence within the community matrix even after translocating periphyton to decontaminated water. We conclude that the exposure concentration modulates the recovery potential of IPA-impacted periphyton. The current research is the first to study the recovery in glyphosate-free water of periphyton exposed to the most commonly used herbicide in the world. Finally, we highlight the need for more studies focused on the recovery potential of freshwater ecosystems and aquatic communities after glyphosate contamination.

Recent studies have shown that sub-lethal doses of herbicides may affect plant flowering, however, no study has established a direct relationship between the concentrations of deposited herbicide and plant flowering. Here the aim was to investigate the relationship between herbicide spray drift deposited on non-target plants and plant flowering in a realistic agro-ecosystem setting. The concentrations of the herbicide glyphosate deposited on plants were estimated by measuring the concentration of a dye tracer applied together with the herbicide. The estimated maximal and average deposition of glyphosate within the experimental area corresponded to 30 g glyphosate/ha (2.08% of the label rate of 1440 g a.i./ha) and 2.4 g glyphosate/ha (0.15% label rate), respectively, and the concentrations decreased rapidly with increasing distance from the spraying track. However, there were not a unique relation between distance and deposition, which indicate that heterogeneities of turbulence, wind speed and/or direction can strongly influence the deposition from 1 min to another during spraying. The effects of glyphosate on cumulative flower numbers and flowering time were modelled using Gompertz growth models on four non-target species. Glyphosate had a significantly negative effect on the cumulative number of flowers on Trifolium pratense and Lotus corniculatus, whereas there were no significant effects on Trifolium repens, and a positive, but non-significant, effect on number of flowers on Cichorium intybus. Glyphosate did not affect the flowering time of any of the four species significantly. Lack of floral resources is known to be of major importance for pollinator declines. The implications of the presented results for pesticide risk assessment are discussed.