An Evolutionarily Conserved Receptor-like Kinases Signaling Module Controls Cell Wall Integrity During Tip Growth

Area of Science:

• Plant Biology
• Cell Biology
• Evolutionary Biology

Background:

• Tip growth is crucial for plant structures like root hairs and pollen tubes, enabling land colonization.
• Cell wall integrity (CWI) maintenance during tip growth requires coordinating cell expansion with cell wall synthesis.
• In Arabidopsis thaliana, CWI is monitored by Malectin-like receptor kinases (MLRs) and PTI1-like kinases.

Purpose of the Study:

• To investigate the role of MLR and PTI1-like signaling in tip growth of the early land plant Marchia polymorpha.
• To determine if the CWI mechanism observed in seed plants is conserved in earlier plant lineages.

Main Methods:

• Genetic analysis of MLR and PTI1-like encoding genes in Marchia polymorpha.
• Phenotypic analysis of rhizoid growth in gene-disrupted mutants.
• Comparative analysis with known CWI mechanisms in Arabidopsis thaliana.

Main Results:

• Rhizoid growth in Marchia polymorpha is regulated by an MLR and PTI1-like signaling module.
• Disruption of these genes affects rhizoid growth similarly to root hairs and pollen tubes in Arabidopsis.
• The identified signaling module is conserved between Marchia polymorpha and Arabidopsis thaliana.

Conclusions:

• The MLR and PTI1-like signaling module controlling CWI during tip growth is conserved across land plants.
• This conserved mechanism was likely present in the common ancestor of all land plants.
• This finding highlights the evolutionary importance of CWI during plant terrestrialization.