Responses of active soil microorganisms facing to a soil biostimulant input compared to plant legacy effects.

Agriculture is changing to rely on agroecological practices that take into account biodiversity, and the ecological processes occurring in soils. The use of agricultural biostimulants has emerged as a valid alternative to chemicals to indirectly sustain plant growth and productivity. Certain BS have been shown to select and stimulate plant beneficial soil microorganisms.

Specific recruitment of soil bacteria and fungi decomposers following a biostimulant application increased crop residues mineralization.

Agriculture is undergoing important changes in order to meet sustainable soil management with respect to biodiversity (namely agroecology). Within this context, alternative solutions to mineral fertilizers such as agricultural biostimulants are thus promoted and being developed. The mechanisms by which some soil biostimulants sustain soil biological functioning and indirectly increase crop yields are still unknown.

A beta-1,3 glucan sulfate induces resistance in grapevine against Plasmopara viticola through priming of defense responses, including HR-like cell death.

Sulfated laminarin (PS3) has been shown previously to be an elicitor of plant defense reactions in tobacco and Arabidopsis and to induce protection against tobacco mosaic virus. Here, we have demonstrated the efficiency of PS3 in protecting a susceptible grapevine cultivar (Vitis vinifera cv. Marselan) against downy mildew (Plasmopara viticola) under glasshouse conditions.

Lipopolysaccharides of Pectobacterium atrosepticum and Pseudomonas corrugata induce different defence response patterns in tobacco, tomato, and potato.

Lipopolysaccharides (LPS), ubiquitous cell surface components of Gram-negative bacteria, are directly implicated in plant/pathogen interactions. However, their perception by the plant, the subsequent signal transduction in both compatible and incompatible interactions, as well as the defence reactions induced in compatible interactions are as yet poorly understood. We focused on biochemical and physiological reactions induced in cell suspensions of three Solanaceae species (tobacco, tomato, and potato) by purified lipopolysaccharides from PECTOBACTERIUM ATROSEPTICUM (PA), a pathogen of potato, and PSEUDOMONAS CORRUGATA (PSC), a pathogen of tomato.

Sulfated fucan oligosaccharides elicit defense responses in tobacco and local and systemic resistance against tobacco mosaic virus.

Sulfated fucans are common structural components of the cell walls of marine brown algae. Using a fucan-degrading hydrolase isolated from a marine bacterium, we prepared sulfated fucan oligosaccharides made of mono- and disulfated fucose units alternatively bound by alpha-1,4 and alpha-1,3 glycosidic linkages, respectively. Here, we report on the elicitor activity of such fucan oligosaccharide preparations in tobacco.