European Journal of Plant Pathology (2011) 131, 393-401

Valérie Jaulneau, Claude Lafitte, Marie-France Corio-Costet, Marciel J. Stadnik, Sylvie Salamagne, Xavier Briand, Marie-Thérèse Esquerré-Tugayé and Bernard Dumas (2011)
An Ulva armoricana extract protects plants against three powdery mildew pathogens
European Journal of Plant Pathology 131 (3), 393-401
Abstract: The protective activity of a crude extract prepared from the green macroalga, Ulva armoricana, previously shown to induce plant defence responses, was evaluated on three plant species, common bean, grapevine and cucumber, cultivated in the greenhouse and inoculated with three powdery mildew pathogens Erysiphe polygoni, E. necator and Sphaerotheca fuliginea respectively. Chemical analyses showed that the extract was enriched in ulvans, which are green algae polysaccharides essentially composed of uronic acid and sulphated rhamnose. Weekly applications were performed by spraying of the green algal extract at various dilutions on bean, grapevine and cucumber leaves. A significant effect (50% protection) was observed using a dilution corresponding to about 3 g l⁻¹ dry matter and up to 90% reduction of symptom severity was obtained for the highest concentration (1/9 dilution, 6 g l⁻¹ dry matter) for the three plant species. To study the natural variability of the protective activity, five extracts prepared from algae batches harvested at different year periods were evaluated. Although polysaccharide composition varied among batches, all extracts elicit a reporter gene regulated by a defence-gene promoter in a transgenic tobacco line, and protect cucumber plants against powdery mildew infection. Together, these data demonstrate that U. armoricana is a reproducible source of active compounds which can be used to efficiently protect crop plants against powdery mildew diseases.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Bernard Dumas, Marciel J. Stadnik, Marie-France Corio-Costet

Research topic(s) for pests/diseases/weeds:
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Erysiphe necator	Grapevine (Vitis)
	Podosphaera fuliginea	Cucumber (Cucumis sativus)
	Erysiphe polygoni	Beans (Phaseolus)