CIPK-B is essential for salt stress signalling in Marchantia polymorpha

Area of Science:

• Plant Biology
• Molecular Biology
• Genetics

Background:

• Calcium signalling is vital for plant processes, with expanded and redundant calcium decoder proteins across the green lineage.
• The liverwort Marchantia polymorpha is a key model plant, but its calcium decoder network remains largely uncharacterized.

Purpose of the Study:

• To identify and characterize the calcineurin B-like (CBL) and CBL-interacting protein kinase (CIPK) network in Marchantia polymorpha.
• To investigate the role of these CBL-CIPK networks in salt stress response.

Main Methods:

• Phylogenetic analyses to identify CBL and CIPK families.
• Gene expression analysis under salt stress.
• Protein-protein interaction studies (yeast two-hybrid, bimolecular fluorescence complementation).
• CRISPR/Cas9 gene editing for knockout analysis.

Main Results:

• Marchantia polymorpha possesses two CIPKs and three CBLs.
• CIPK and CBL genes exhibit salt-responsive transcriptional changes.
• All identified M. polymorpha CBL-CIPKs interact in planta.
• Knockout of CIPK-B increases salt sensitivity, implicating it in salt signalling.

Conclusions:

• The study identifies a functional CBL-CIPK network in M. polymorpha involved in salt tolerance.
• Phylogenetic and interaction data suggest an evolutionarily conserved salt overly sensitive pathway.
• These findings highlight early roles for CBL-CIPK networks in abiotic stress tolerance, potentially linked to land plant emergence.