Touch signaling and thigmomorphogenesis are regulated by complementary CAMTA3- and JA-dependent pathways
Essam Darwish1,2, Ritesh Ghosh1, Abraham Ontiveros-Cisneros1
1Department of Biology, Lund University, Lund, Sweden.
Science Advances
|May 20, 2022
Summary
Plants use touch signaling for growth and defense. This study identifies calmodulin-binding transcriptional activators (CAMTA1/2/3) as key regulators of jasmonic acid-independent touch responses, impacting plant development and flowering.
Area of Science:
- Plant biology
- Mechanobiology
- Molecular signaling
Background:
- Plants exhibit thigmomorphogenesis, altering growth and flowering in response to mechanical stimuli like touch.
- Jasmonic acid (JA) is known to be involved in touch signaling pathways.
- The precise molecular mechanisms underlying plant touch responses remain incompletely understood.
Purpose of the Study:
- To elucidate the molecular regulators of plant touch signaling pathways.
- To differentiate between JA-dependent and JA-independent touch response mechanisms.
- To characterize the roles of specific genes and proteins in mediating thigmomorphogenesis.
Main Methods:
- Utilized reverse genetics approaches to study plant responses to mechanical stimuli.
- Investigated the function of Piezo mechanosensitive ion channels in touch signaling.
- Analyzed the role of the receptor-like kinase Feronia in JA-dependent touch signaling.
- Examined the function of calmodulin-binding transcriptional activators (CAMTA1/2/3) in JA-independent touch signaling.
Main Results:
- Piezo channels play a minor role in touch-induced gene expression and thigmomorphogenesis.
- Feronia acts as a negative regulator of the JA-dependent touch signaling pathway.
- CAMTA1/2/3 directly bind to promoters of JA-independent touch marker genes (e.g., TCH2, TCH4), activating their expression.
- Mutations in CAMTA3 result in a significant loss of thigmomorphogenesis and delayed flowering upon touch stimulus.
Conclusions:
- Identified CAMTA1/2/3 as crucial regulators of JA-independent touch signaling in plants.
- Demonstrated that Feronia negatively regulates the JA-dependent touch pathway.
- Uncovered two distinct, key regulators controlling independent touch-signaling pathways in plants.
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