Dynamics and regulation of jasmonic acid and salicylic acid transcriptional networks in Arabidopsis.
R. HICKMAN (1), M. Van Verk (1), A. Van Dijken (1), K. Denby (2), C. Pieterse (1), S. Van Wees (1) (1) Utrecht University, Netherlands; (2) Warwick University, United Kingdom

The phytohormones jasmonic acid (JA) and salicylic acid (SA) are critical regulators of immune responses that respond to different types of attacker. We performed a high-resolution RNA-Seq time series analysis of JA- and SA-treated Arabidopsis thaliana leaves to obtain a detailed map of transcriptional reprogramming induced by these hormones at 15 timepoints over a continuous 16-h time period. Analysis of these high-resolution transcription profiles allowed us to construct a chronology of transcriptional events induced by JA and SA, while clustering of the highly informative expression profiles revealed regulatory modules that are enriched for specific functions and regulators. By mapping of transcription factor binding motifs in these clusters we were able to predict regulatory interaction modules, with one predicted novel local network being experimentally validated. In addition, several novel regulators of early hormone induced responses were inferred from the gene regulatory network and experimentally validated using mutant lines in bioassays that test for altered responses to hormone-relevant attackers; further network validation is ongoing. This combined computational and experimental approach provides a highly detailed picture of the transcriptional regulatory networks that control JA and SA responsive genes, and is a valuable resource for the plant science community.

Abstract Number: P16-452
Session Type: Poster