Investigating induction of SAR in during gene- for-gene interactions between Arabidopsis thaliana and Pseudomonas syringae
T. GAIKWAD (1), M. Grant (2), M. de Torres-Zabala (1), P. Winlove (3), S. Green (3), D. Horsell (3) (1) Biosciences, College of Life and Environmental Sciences, University of Exeter, UK, United Kingdom; (2) Biosciences,College of Life and Environmental Sciences, University of Exeter,UK., United Kingdom; (3) Physics, College of Engineering, Mathematics and Physics, University of Exeter.UK., United Kingdom

Plants have two core defense mechanisms against microbial pathogens; (i) Recognition of Pathogen-Associated Molecular Patterns (PAMPs) by extracellular surface receptors leading to the activation of PAMP-Triggered Immunity (PTI); (ii) Recognition of pathogen effector activity by host Resistance (R) proteins leading to Effector-Triggered Immunity (ETI). ETI is usually characterised by rapid localised Hypersensitive Response (HR). HR can also induce Systemic Acquired Resistance (SAR) through the production of inducible immune signal(s), leading to a broad spectrum systemic resistance. We aim to understand the earliest events associated with SAR signaling using electrophysiology, SAR mutants and a unique promoter-luciferase fusion that captures early propagative transcriptional events underlying initiation of systemic immune signal(s). We describe the transcriptional dynamics of A70 (At5g56980), a gene of unknown function (Truman et al. 2006), in local and systemic tissue following challenge with different elicitors and virulent or avirulent pathogen challenges. We provide evidence that A70 responds to a jasmonate (JA) related signal that is rapidly generated following ETI recognition. We further evaluate A70::LUC reporter activity in response to JA stimulus and correlate activity with histological expression of a JA repressor reporter (JAZ10::GUS) in systemic responding leaves following different bacterial challenges. Finally, we examine changes in electrophysiological signals following ETI in local and systemic leaves. We conclude that there are strong links between ETI induced electrical signals, activation of A70::LUC expression in petioles of infected leaves and adjacent systemic tissues and the spatial pattern of JAZ10::GUS expression in responding tissues.

Abstract Number: P18-671
Session Type: Poster