Responses to pathogens, including host transcriptional reprogramming, require partially antagonistic signalling pathways dependent on the phytohormones salicylic (SA) and jasmonic (JA) acids. However, upstream factors modulating the interplay of these pathways are not well characterized. Here, we identify the transcription factor ANAC032 from Arabidopsis thaliana as one such regulator in response to the bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (Pst). ANAC032 directly represses MYC2 activation upon Pst attack, resulting in blockage of coronatine‐mediated stomatal reopening which restricts entry of bacteria into plant tissue. Furthermore, ANAC032 activates SA signalling by repressing NIMIN1, a key negative regulator of SA‐dependent defence. Finally, ANAC032 reduces expression of JA‐responsive genes, including PDF1.2A. Thus, ANAC032 enhances resistance to Pst by generating an orchestrated transcriptional output towards key SA‐ and JA‐signalling genes coordinated through direct binding of ANAC032 to the MYC2, NIMIN1 and PDF1.2A promoters.
This study reports a novel NAC transcription factor ANAC032 in Arabidopsis as a positive regulator of plant defence against Pseudomonas syringae. ANAC032 promotes SA‐mediated defence signalling, but negatively regulates JA‐mediated responses.
Arabidopsis ANAC032 enhances resistance to Pseudomonas syringae.
ANAC032 promotes SA‐mediated defence signalling by repressing NIMIN1, a negative regulator of SA‐dependent defence.
ANAC032 transcriptionally represses MYC2, a key JA activator, and restricts entry of bacteria into plant tissue.
- Received February 12, 2016.
- Revision received August 19, 2016.
- Accepted August 23, 2016.
- © 2016 The Authors