Multifunctional polysaccharides bioformulations to enhance wheat (Triticum aestivum) adaptation to environmental stress condition.

International audienceCurrent needs in Sustainable Agricultural Systems require the decrease of conventional pesticides and fertilizers. Nowadays, biomolecules are associated with a newly form of agricultural practices that could reduce the use of agrochemical products and ensure plant adaptation to environmental stress conditions such as drought and thermal stress. For example, polysaccharides from algae (alginate) and mushrooms (chitosan) can be used as a microcarriers, providing diverse active molecules like macro- or micro-nutrients, polymers and oligomers which are known to enhance plant adaptation in response to different stress. Indeed, they are known to induce the production of Pathogenesis Related proteins (PR proteins), which stimulate plant defense mechanisms, forewarning against biotic stress and are involved in plant signalization of abiotic stress. In addition, they have a capacity to reticulate with ionic crosslinkers like phosphates and calcium salts to trap water molecules which would have a role in the cell ionic equilibrium. Conceptually, a multifunctional biostimulation can occur in the plant in synergy through polysaccharides, ions and water inputs. Our project aims at generating natural polysaccharidic bioformulations and evaluating their potential effect on wheat tolerance under water and thermal stress at different scales. Firstly, molecular and physiological analyses will be carried out under controlled conditions in order to determine the suitable applications and concentrations of bioactive molecules. Then, using semi controlled platform dedicated to wheat phenotyping under different water regimes (Pheno3C, UMR GDEC-INRAE Crouël, France), experiments will be performed to validate the effect of the bioformulations under natural field conditions. Finally, some of the most promising bioformulated products will be tested in field using farmers’ trials under the supervision of the Agricultural French Cooperative Oxyane. In parallel, total fungi biomass and seed storage proteins of treated plots will be estimated to determine the effect of the bioformulations on the rhizosphere composition and the migrations of nutrients during grain maturation

Sunflower resistance to French races of downy mildew (Plasmopara halstedii)

Three races of downy mildew (1, A, B) have been observed on sunflowers in France. Until recently, all genotypes resistant to race A were resistant to the less virulent races 1 and B. Some genotypes have now been identified as resistant to races 1 and A but susceptible to race B.Il existe en France 3 races de Plasmopara halstedii, agent du mildiou du tournesol, Helianthus annuus L : la race 1, la race B et la race A. Tous les génotypes résistants à la race A étaient également résistants aux 2 autres races. Cette possibilité pouvait être exploitée par les sélectionneurs en utilisant uniquement la race A pour sélectionner pour la résistance simultanée aux autres races françaises. Cependant, la mise en évidence du comportement de la lignée QHP1 et de 2 populations, HAR4 et HAR5, qui sont résistantes à la race A mais sensibles à la race B, remet en question cette stratégie de sélection et imposerait l’utilisation de 2, voire des 3 races françaises

The effects of mycorrhizal fungi on vascular wilt diseases

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Molecular analysis of a major locus for resistance to downy mildew in sunflower with specific PCR-based markers

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Molecular analysis of a major locus for resistance to downy mildew in sunflower with specific PCR-based markers

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