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Updated: May 14, 2026
Pattern-Triggered Oxidative Burst and Seedling Growth Inhibition Assays in Arabidopsis thaliana
Published on: May 21, 2019
The anticipation of danger: microbe-associated molecular pattern perception enhances AtPep-triggered oxidative burst
Pascale Flury1, Dominik Klauser, Birgit Schulze
1Zürich-Basel Plant Science Center, Department of Environmental Sciences, University of Basel, Hebelstrasse 1, CH-4056 Basel, Switzerland.
Abstract:
The endogenous Arabidopsis (Arabidopsis thaliana) peptides, AtPeps, elicit an innate immune response reminiscent of pattern-triggered immunity. Detection of various danger signals, including microbe-associated molecular patterns (MAMPs), leads to elevated transcription of PROPEPs, the AtPep precursors, and PEPRs, the AtPep receptors. It has been hypothesized that AtPeps are involved in enhancing pattern-triggered immunity. Following this idea, we analyzed the relationship between MAMP- and AtPep-elicited signaling. We found that the perception of MAMPs enhanced a subsequent AtPep-triggered production of reactive oxygen species (ROS). Intriguingly, other components of AtPep-triggered immunity like Ca(2+) influx, mitogen-activated protein kinase phosphorylation, ethylene production, and expression of early defense genes, as well as ROS-activated genes, remained unchanged. By contrast, treatment with methyl jasmonate promoted an increase of all analyzed AtPep-triggered responses. We positively correlated the intensities of generic AtPep-triggered responses with the abundance of the two AtPep receptors by generating constitutively expressing PEPR1 and PEPR2 transgenic lines and by analyzing pepr1 and pepr2 mutants. Further, we show that enhanced, as well as basal, ROS production triggered by AtPeps is absent in the double mutant of the respiratory burst oxidase homologs D and F (rbohD rbohF). We present evidence that the enhancement of AtPep-triggered ROS is not based on changes in the ROS detoxification machinery and is independent of mitogen-activated protein kinase and Ca(2+) signaling pathways. Taken together, these results indicate an additional level of regulation besides receptor abundance for the RbohD/RbohF-dependent production of AtPep-elicited ROS, which is specifically operated by MAMP-triggered pathways.
Insights
Microbe-associated molecular patterns (MAMPs) prime plants for enhanced immunity. MAMP perception specifically boosts AtPep-triggered reactive oxygen species (ROS) production, revealing a novel regulatory layer in plant defense signaling.
Area of Science:
- Plant immunity
- Plant signaling pathways
- Molecular plant-pathogen interactions
Background:
- Endogenous Arabidopsis (Arabidopsis thaliana) peptides (AtPeps) are involved in innate immunity.
- AtPep signaling is linked to pattern-triggered immunity (PTI), a plant defense response.
- Microbe-associated molecular patterns (MAMPs) trigger PTI, leading to increased transcription of PROPEPs and PEPRs.
Purpose of the Study:
- To investigate the relationship between MAMP- and AtPep-elicited signaling pathways in Arabidopsis.
- To determine how MAMP perception influences AtPep-triggered immune responses, particularly reactive oxygen species (ROS) production.
- To elucidate the regulatory mechanisms controlling AtPep-induced ROS production.
Main Methods:
- Analysis of ROS production, Ca(2+) influx, mitogen-activated protein kinase (MAPK) phosphorylation, ethylene production, and defense gene expression.
- Generation and analysis of transgenic Arabidopsis lines overexpressing PEPR1 and PEPR2, and analysis of pepr1 and pepr2 mutants.
- Investigation of the role of respiratory burst oxidase homologs D and F (rbohD rbohF) in AtPep-triggered ROS production.
Main Results:
- MAMP perception significantly enhanced subsequent AtPep-triggered ROS production, while other responses remained largely unchanged.
- Methyl jasmonate treatment promoted all analyzed AtPep-triggered responses.
- AtPep-triggered ROS production is dependent on RbohD and RbohF, and its enhancement by MAMPs is independent of MAPK and Ca(2+) signaling.
Conclusions:
- MAMP-triggered pathways provide an additional regulatory mechanism for AtPep-elicited ROS production, acting independently of receptor abundance.
- The regulation of AtPep-induced ROS production involves RbohD/RbohF and is specifically modulated by MAMP-triggered pathways.
- This study reveals a specific enhancement of ROS production as a key component of MAMP-primed AtPep signaling.
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