Plant immunity in Arabidopsis thaliana ecotypes with natural variations in defense related genes
N. SCHOLTEN (1), J. Zeier (1) (1) Heinrich-Heine-Universität Düsseldorf, Germany

To combat pathogens, plants have evolved a multi-layered immune system that is controlled by a complex signaling network. Due to the arms race between pathogens and host plants during co-evolution, defense related genes are under a constant pressure of specification. The phenolic salicylic acid (SA) and the non-protein amino acid pipecolic acid (Pip) are crucial players for basal immunity and the establishment of systemic acquired resistance (SAR) in plants. Exogenously applied Pip and SA are able to induce priming of defense responses (i.e. rendering them faster and stronger). To investigate conserved roles of SA and Pip in plant defense, we focused on natural variation of defense related genes in different Arabidopsis thaliana ecotypes. Basal and systemic immunity of the ecotypes was assessed by comparative metabolic profiling via GC/MS and bacterial growth assays, yielding ecotypes with naturally enhanced resistance against Pseudomonas syringae pv. maculicola ES4326 (Psm) compared to Col-0. More resistant ecotypes showed higher basal levels of Pip and SA in their leaves. However, these plants were compromised in SAR against Psm and priming by exogenously applied Pip, pointing to a lack of responsiveness to SA and Pip due to already elevated basal levels of these compounds. We therefore conclude that basal resistance correlates with basal levels of Pip and SA and propose that the role of these signals for plant immunity might be conserved in different Arabidopsis ecotypes.

Abstract Number: P16-468
Session Type: Poster