S14 - Session P2 - Development of a new crop protection strategy against fungal diseases: the Sensitines®

Authors: Ophélie Dubreu *, Thomas Guillemette, Marie-Noëlle Brisset, Emmanuel Pajot

Each year, more than a quarter of crop yield is lost, especially due to fungal pathogens. Fungicides, are commonly used to control these pathogens but they are progressively removed from the market due to environment and human health impacts. Enhancing the quality and productivity of crops with minimal chemical inputs will be notably achieved by the development of new crop protection strategies. To date, several alternatives, such as Plant Resistance Inducers (PRI), are being deployed but they are currently less efficient than fungicides. The aim of this project is to develop a new strategy exploiting a patent filed by the University of Angers in 2012, which could complement the use of PRI. This patent describes molecules called Sensitines ® able, at low concentration, to weaken the fungal adaptive response to plant defense molecules by targeting specific pathways. Once the fungi weakened, applying additional biocontrol products should be more efficient, especially those targeting the induction of plant defenses such as PRI. A synergistic effect is thus expected which could allow to reach the efficiency of conventional phytosanitary products. To develop the Sensitines® concept, the first step was to find and confirm a plant extract resource exhibiting Sensitines® activity. For this purpose, the chemical composition of several plant extracts has been characterized followed by the in vitro assessment of their inhibitory effect on fungal growth. Both results led to the selection of one plant extract called Sensitines®QBA. The next step was to investigate the ability of Sensitines®QBA to enhance the sensitivity of fungi to phytoalexins (plant defense molecules). An increased lethal effect has been thus demonstrated for an indolic phytoalexin from Brassicaceae (camalexin) against Alternaria brassicicola when Sensitines®QBA was added to the fungal culture. Finally, assessment of a synergistic effect in planta between Sensitines®QBA and various commercial PRI is currently in progress.