Aberrant growth and expansion in Penium margaritaceum triggered by disruption of microtubules and the cell wall.

This article focuses on the cellular mechanisms underlying cell expansion and morphogenesis in the unicellular zygnematophyte Penium margaritaceum, particularly examining the roles of cell wall integrity and the cytoskeleton. Using treatments with pectate lyase (PL), a fungal enzyme that degrades pectin, and amiprophos methyl (APM), a microtubule-disrupting agent, the study reveals that pectin degradation induces additional expansion zones while microtubule disruption causes swelling at the primary expansion zone (the isthmus). Combined PL and APM treatment leads to distinct dumbbell-shaped cells with altered internal ultrastructure, including septum formation and displacement of organelles, demonstrating that coordination between the cell wall and cytoskeletal elements is critical for defining expansion and division sites. These findings provide insights into cell wall integrity monitoring and cytoskeletal functions in streptophyte algae, which may have been important in the evolution of land plants.