Interplay between calcium signalling and early signalling elements during defence responses to microbe- or
Stefanie Ranf1, Lennart Eschen-Lippold, Pascal Pecher
1Leibniz Institute of Plant Biochemistry, Stress and Developmental Biology, Weinberg 3, D-06120 Halle, Germany.
The Plant Journal : for Cell and Molecular Biology
|June 15, 2011
Summary
Plant immune receptors show specific responses to microbe- or damage-associated molecular patterns (MAMPs/DAMPs). BAK1 kinase and reactive oxygen species (ROS) fine-tune calcium (Ca2+) signaling and defense gene expression in Arabidopsis thaliana.
Area of Science:
- Plant immunity
- Molecular signaling pathways
- Plant-microbe interactions
Background:
- Microbe- or damage-associated molecular patterns (MAMPs/DAMPs) typically elicit common intracellular signaling events.
- Specific differences in plant responses to MAMPs suggest complex regulatory mechanisms.
Purpose of the Study:
- To investigate MAMP-specific differences in calcium (Ca2+) signaling, defense gene expression, and growth arrest in Arabidopsis thaliana.
- To elucidate the role of BAK1 kinase and reactive oxygen species (ROS) in modulating these MAMP-triggered responses.
Main Methods:
- Comparative analysis of flg22 and elf18 MAMPs in wild-type and bak1 mutant Arabidopsis thaliana.
- Assessment of Ca2+ signaling, defense gene expression, and growth inhibition.
- Investigation of ROS production and its impact on Ca2+ signaling using rbohD mutants and inhibitors.
- Analysis of mpk3 mutants to understand ROS feedback on Ca2+ responses.
Main Results:
- MAMPs flg22 and elf18 induced distinct Ca2+ signaling, defense gene expression, and growth arrest patterns.
- BAK1 kinase significantly influenced flg22-mediated responses but had minimal effects on elf18-elicited reactions.
- Reactive oxygen species (ROS) accumulation demonstrated a feedback effect on Ca2+ signaling, particularly on the second Ca2+ peak.
- Mpk3 mutants showed prolonged ROS accumulation without significantly altering the overall Ca2+ response.
Conclusions:
- Fine-tuning of MAMP/DAMP responses involves intricate interplay between signaling elements upstream and downstream of Ca2+ signaling.
- BAK1 plays a crucial role in differential signal amplification for MAMP/DAMP perception.
- ROS acts as a feedback regulator of Ca2+ signaling in plant immunity.
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