Crisis Management of Chronic Pollution: Contaminated Soil and Human Health deals with a long term pollution problem, generated by the former use of organochlorine pesticides. Through a case study of the chlordecone pollution in the French West Indies, the authors illustrate a global and systemic mobilization of research institutions and public services. This "management model", together with its major results, the approach and lessons to be learned, could be useful to other situations. This book gathers all the works that have been carried out over the last ten years or more and links them to decision makers' actions and stakeholders' expectations. This reference fills a gap in the literature on chronic pollution. (Résumé d'auteur)

This is the second part of a Special Issue on developments and applications of the Soil and Water Assessment Tool (SWAT) related to agricultural water and nonpoint source pollution management at a watershed scale (see Volk et al., 2016 for part I).

Ocean acidification (OA), induced by rapid anthropogenic CO2 rise and its dissolution in seawater, is known to have consequences for marine organisms. However, knowledge on the evolutionary responses of phytoplankton to OA has been poorly studied. Here we examined the coccolithophore Gephyrocapsa oceanica, while growing it for 2000 generations under ambient and elevated CO2 levels. While OA stimulated growth in the earlier selection period (from generations 700 to 1550), it reduced it in the later selection period up to 2000 generations. Similarly, stimulated production of particulate organic carbon and nitrogen reduced with increasing selection period and decreased under OA up to 2000 generations. The specific adaptation of growth to OA disappeared in generations 1700 to 2000 when compared with that at 1000 generations. Both phenotypic plasticity and fitness decreased within selection time, suggesting that the species' resilience to OA decreased after 2000 generations under high CO2 selection.

National audience | Zymoseptoria tritici, responsible for Septoria tritici blotch, is the most important pathogen of wheat. The control of this parasite relies mainly on synthetic fungicides, but their use is increasingly controversial and searching for alternative management strategies is encouraged. In this context, the biocontrol potential of crude methanolic extracts of eight extremophile plant species from Tunisia, including three xerophytes and five halophytes, against Z. tritici was assessed. Only the extract of Juncus maritimus rhizomes showed significant in vitro antifungal activity. In extremophile plants, the production of secondary metabolites is often influenced by abiotic conditions. Thus, we collected several samples of J. maritimus rhizomes at different vegetative stages, at different periods, and from different substrates to compare their antifungal activities. Our results suggest that the plant environment, especially the substrate of the soil, should be taken into account to identify great sources of natural antifungal products. From the most active sample, a 9,10-dehydrophenanthrene derivative, effusol, absent from other J. maritimus rhizomes extracts, was purified. This product showed a strong antifungal activity against the pathogen, with a minimal inhibitory concentration of 19gmL(-1) and an half-maximal inhibitory concentration of 9.98gmL(-1). This phenanthrene derivative could be a promising biocontrol molecule against Z. tritici.

International audience | Bacteria belonging to the genus Burkholderia live in various ecological niches and present a significant role in the environments through the excretion of a wide variety of secondary metabolites including modular nonribosomal peptides (NRPs) and polyketides (PKs). These metabolites represent a widely distributed biomedically and biocontrol important class of natural products including antibiotics, siderophores, and anticancers as well as biopesticides that are considered as a novel source that can be used to defend ecological niche from competitors and to promote plant growth. The aim of this review is to present all NRPs produced or potentially produced by strains of Burkholderia, as NRPs represent a major source of active compounds implicated in biocontrol. The review is a compilation of results from a large screening we have performed on 48 complete sequenced genomes available in NCBI to identify NRPS gene clusters, and data found in the literature mainly because some interesting compounds are produced by strains not yet sequenced. In addition to NRPs, hybrids NRPs/PKs are also included. Specific features about biosynthetic gene clusters and structures of the modular enzymes responsible for the synthesis, the biological activities, and the potential uses in agriculture and pharmaceutical of NRPs and hybrids NRPs/PKs will also be discussed.

National audience | In this study, we have investigated the effects of three lipopeptides (fengycin, surfactin and mycosubtilin) produced by different strains of Bacillus subtilis against the phytopathogenic fungi Fusarium oxysporum f. sp. iridacearum, which affects the ornamental bulb plant populations of Iris sp. The antifungal effects were tested using minimum inhibitory concentration assay, determination of mycelium growth and spore germination inhibition rates. Also, in vivo tests on infected rhizomes and scanning electron microscopy were employed. Mycosubtilin alone and in combination with fengycin or/and surfactin showed potent inhibitory activity at concentrations as low as 5gml(-1) which is 100 times lower compared to Topsin M, a common chemical fungicide frequently used against fusariosis in ornamental plants. An enhancement of mycosubtilin antifungal activity was observed when it was used in combination with surfactin due to a synergistic effect. At a concentration of 20gml(-1), mycosubtilin inhibited the growth of the mycelium up to 49% and the spore germination ability up to 26% in comparison to control. In addition, significant changes on the macro- and micro-morphology have been observed. The antifungal activity is related to the inhibition of spore germination and the irreversible damage of the hyphae cell wall. To the best of our knowledge, this is the first attempt to propose the lipopeptides as biopesticides against the fusariosis of ornamental plants.

National audience | In this work, the behavior in tomato rhizosphere of Bacillus velezensis FZB42 was analyzed taking into account the surfactin production, the use of tomato roots exudate as substrates, and the biofilm formation. B. velezensis FZB42 and B. amyloliquefaciens S499 have a similar capability to colonize tomato rhizosphere. Little difference in this colonization was observed with surfactin non producing B. velezensis FZB42 mutant strains. B. velezensis is able to grow in the presence of root exudate and used preferentially sucrose, maltose, glutamic, and malic acids as carbon sources. A mutant enable to produce exopolysaccharide (EPS-) was constructed to demonstrate the main importance of biofilm formation on rhizosphere colonization. This mutant had completely lost its ability to form biofilm whatever the substrate present in the culture medium and was unable to efficiently colonize tomato rhizosphere.

Le concept de programmation fœtale revient à admettre qu’il existe un impact des conditions environnementales dans lesquelles l’individu se développe in utero (via l’exposition de la mère) pouvant l’affecter à long terme. Le projet "BRAINAIRPOLL" s’inscrit dans le prolongement du programme de recherche "EPAPP" (Effets de la Pollution Atmosphérique sur la fonction Placentaire et le développement Postnatal), dont les résultats encore préliminaires confirment l’impact de la pollution atmosphérique liée à l’émission de fumées diesel sur le développement foeto-placentaire et la toxicité potentielle de l’exposition précoce à ce type d’émissions.