NINJA-associated ERF19 negatively regulates Arabidopsis pattern-triggered immunity

Area of Science:

• Plant immunity
• Molecular plant-pathogen interactions
• Plant signaling pathways

Background:

• Pattern-triggered immunity (PTI) is a crucial plant defense mechanism initiated by recognizing microbe-associated molecular patterns (MAMPs).
• Transcription factors (TFs) play vital roles in regulating PTI through complex signaling networks.
• Ethylene response factor (ERF) proteins are involved in various plant processes, including stress responses.

Purpose of the Study:

• To characterize the function of ERF19, an Arabidopsis thaliana ethylene response factor (ERF), in plant immunity.
• To investigate the role of ERF19 in pattern-triggered immunity (PTI) against fungal and bacterial pathogens.
• To identify regulatory interactions involving ERF19 in plant defense signaling.

Main Methods:

• Genetic analysis using Arabidopsis thaliana lines overexpressing ERF19 or expressing the dominant repressor ERF19-SRDX.
• Pathogen infection assays with Botrytis cinerea (fungus) and Pseudomonas syringae (bacteria).
• Biochemical assays to determine protein-protein interactions, specifically between ERF19 and Novel INteractor of JAZ (NINJA).

Main Results:

• ERF19 acts as a negative regulator of PTI, as its overexpression increased susceptibility to B. cinerea and P. syringae.
• ERF19 overexpression repressed MAMP-induced PTI outputs, while ERF19-SRDX expression enhanced PTI and resistance.
• The transcriptional co-repressor NINJA was found to associate with and repress ERF19 function.

Conclusions:

• ERF19 is a novel negative regulator involved in mitigating plant pattern-triggered immunity (PTI).
• NINJA plays a role in fine-tuning ERF19-mediated regulation of Arabidopsis innate immunity.
• Understanding ERF19 and NINJA interactions provides insights into the complex regulation of plant defense responses.