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Updated: Feb 6, 2026
02:54
Protein Modifications: Protein Kinases and Phosphatases
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Network properties of robust immunity in plants
Kenichi Tsuda1, Masanao Sato, Thomas Stoddard
1Department of Plant Biology, Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, Minnesota, USA.
Plos Genetics
|December 17, 2009
Summary
Plant immunity relies on jasmonic acid (JA), ethylene (ET), and salicylic acid (SA) signaling. This study reveals these pathways synergize in Pattern-Triggered Immunity (PTI) and compensate in Effector-Triggered Immunity (ETI) for robust plant defense.
Area of Science:
- Plant immunity
- Molecular plant-microbe interactions
- Plant signaling pathways
Background:
- Plant immunity involves Effector-Triggered Immunity (ETI) and Pattern-Triggered Immunity (PTI).
- Jasmonic acid (JA)/ethylene (ET) and salicylic acid (SA) signaling pathways are crucial for plant defense but their precise roles in ETI and PTI are unclear.
- These pathways are generally considered antagonistic, with SA mediating biotrophic pathogen defense and JA/ET mediating necrotrophic pathogen defense.
Purpose of the Study:
- To elucidate the roles and interactions of JA, ET, and SA signaling pathways in ETI and PTI.
- To investigate the contribution of these pathways to immunity against both biotrophic and necrotrophic pathogens.
- To analyze the signaling network overlap and differences between ETI and PTI.
Main Methods:
- Construction of an Arabidopsis quadruple mutant (dde2/ein2/pad4/sid2) lacking key components of JA, ET, and SA signaling.
- Quantitative measurement of bacterial growth (Pseudomonas syringae) in leaves to assess ETI (triggered by AvrRpt2) and PTI (triggered by flg22).
- Assessment of immunity against the necrotrophic fungal pathogen Alternaria brassicicola.
- Statistical analysis using a mixed general linear model to determine gene effects and interactions.
Main Results:
- ETI and PTI were largely abolished in the quadruple mutant, indicating the essential roles of JA, ET, and SA signaling in both immunity types.
- Immunity against both biotrophic and necrotrophic pathogens was severely compromised in the quadruple mutant.
- Signaling allocation analysis revealed that JA, ET, and SA signaling positively contribute to immunity against both pathogen types, contrary to previous assumptions.
- ETI and PTI utilize a highly overlapping signaling network, but their utilization differs: PTI involves synergistic relationships, while ETI involves compensatory relationships.
Conclusions:
- Contrary to established models, JA, ET, and SA signaling pathways are not strictly specialized and positively contribute to both biotrophic and necrotrophic immunity.
- PTI relies on synergistic interactions among signaling pathways to amplify defense signals.
- ETI employs compensatory relationships among signaling pathways, ensuring robust defense against diverse pathogen challenges and genetic perturbations.
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