Export of salicylic acid from the chloroplast requires the multidrug and toxin extrusion-like transporter EDS5

Mario Serrano (1) , Bangjun Wang (1, 2) , Bibek Aryal (1) , Christophe Garcion (3, 1) , Eliane Abou-Mansour (1) , Silvia Heck (1, 4) , Markus Geisler (1) , Felix Mauch (1) , Christiane Nawrath (1, 5) , Jean-Pierre Métraux (1)

1 Department of Biology
2 Southwest University
3 BFP - Biologie du fruit et pathologie
4 Angiomed GmbH
5 UNIL - Université de Lausanne = University of Lausanne

Salicylic acid (SA) is central for the defense of plants to pathogens and abiotic stress. SA is synthesized in chloroplasts from chorismic acid by an isochorismate synthase (ICS1); SA biosynthesis is negatively regulated by autoinhibitory feedback at ICS1. Genetic studies indicated that the multidrug and toxin extrusion transporter ENHANCED DISEASE SUSCEPTIBILITY5 (EDS5) of Arabidopsis (Arabidopsis thaliana) is necessary for SA accumulation after biotic and abiotic stress, but so far it is not understood how EDS5 controls the biosynthesis of SA. Here, we show that EDS5 colocalizes with a marker of the chloroplast envelope and that EDS5 functions as a multidrug and toxin extrusion-like transporter in the export of SA from the chloroplast to the cytoplasm in Arabidopsis, where it controls the innate immune response. The location at the chloroplast envelope supports a model of the effect of EDS5 on SA biosynthesis: in the eds5 mutant, stress-induced SA is trapped in the chloroplast and inhibits its own accumulation by autoinhibitory feedback.

Domaines: Biologie végétale

Mario Serrano, Bangjun Wang, Bibek Aryal, Christophe Garcion, Eliane Abou-Mansour, et al.. Export of salicylic acid from the chloroplast requires the multidrug and toxin extrusion-like transporter EDS5. Plant Physiology, 2013, 162 (4), pp.1815-1821. ⟨10.1104/pp.113.218156⟩. ⟨hal-02650838⟩