Search for New tools in Plant Protection: Priming as a mean of stimulating plant defense (PRIDE)

Coordination: Patrick Saindrenan

Industrial partner: Confidential

Priming plant defenses is characterized by the increased capacity to mobilize cellular defense responses following challenge by a broad spectrum of pathogens. Phosphite (Phi), an oxyanion of phosphorous acid (H3PO3), exclusively protects plants against diseases caused by oomycetes by priming salicylic acid (SA)-dependent defense responses following infection. BTH [benzo (1,2,3) thiadiazole-7-carbothioic acid S-methyl ester], a functional analog of SA and an inducer of systemic acquired resistance (SAR), was reported to prime defense genes and supply protection in the field against a broad spectrum of diseases including mainly biotrophic and some necrotrophic fungi. We developed a specific combination of Phi and BTH against Botrytis cinerea and Hyaloperonospora parasitica infecting Arabidopsis thaliana. We showed that the two priming agents exhibit a potential additive/synergistic effect against both pathogens. No antagonistic effect was observed when using together the two priming agents. Dissection of BTH-induced priming was performed and suggested a role of SA signaling and the involvement of the redox status in local induced resistance to B. cinerea. It is expected that the increased spectrum of activity of both priming agents in combination will lead to new alternative strategies in crop protection. We strongly believe that a new area of research is open through the early modification of redox status by using modifiers of this redox status. Further investigations are needed to unravel the mechanism underlying the BTH-priming phenomenon.