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The GSK3/Shaggy-Like Kinase ASKα Contributes to Pattern-Triggered Immunity
Hansjörg Stampfl1, Marion Fritz1, Silvia Dal Santo1
1Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, 1030 Vienna, Austria (H.S., M.F., S.D.S., C.J.); andHealth and Environment Department, Bioresources Unit, AIT-Austrian Institute of Technology, 3430 Tulln, Austria (H.S., C.J.).
Plant Physiology
|May 22, 2016
Summary
Plant immunity relies on pattern recognition receptors (PRRs) detecting pathogen-associated molecular patterns (PAMPs). We found ASKα kinase regulates plant defense by activating G6PD, linking PAMP perception to metabolic changes.
Area of Science:
- Plant Biology
- Molecular Plant Pathology
- Biochemistry
Background:
- Plant immunity involves pattern-triggered immunity (PTI) initiated by pattern recognition receptors (PRRs) sensing conserved microbial molecules (PAMPs).
- Downstream signaling pathways of PTI are not fully understood, particularly how initial perception translates into defense responses.
Purpose of the Study:
- To identify novel regulators of plant immune signaling downstream of PRRs.
- To elucidate the molecular mechanism linking PAMP perception to metabolic adjustments during plant defense.
Main Methods:
- Genetic analysis of Arabidopsis thaliana mutants and overexpression lines for ASKα and G6PD6.
- Biochemical assays to measure kinase activity and phosphorylation events.
- Assessment of PTI responses, including PAMP-induced growth inhibition and pathogen susceptibility.
Main Results:
- ASKα (a GSK3/Shaggy-like kinase) acts as a positive regulator of PTI, with its activity rapidly induced by PAMP perception.
- ASKα directly phosphorylates and activates Glucose-6-phosphate dehydrogenase 6 (G6PD6), a key enzyme in the oxidative pentose phosphate pathway.
- Modulating ASKα or G6PD6 levels altered PTI responses and susceptibility to Pseudomonas syringae, with specific G6PD6 phosphorylation states affecting PAMP-induced growth inhibition.
Conclusions:
- ASKα and G6PD6 form a crucial immune signaling module downstream of PRRs.
- This module connects PAMP perception and protein phosphorylation cascades to the metabolic regulation required for effective plant defense.
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