A biophysical model for plant cell plate maturation based on the contribution of a spreading force

The late-stage onset of an areal spreading and stabilizing force is essential for regular plant cell plate development and maturation. Plant cytokinesis, a fundamental process of plant life, involves de novo formation of a cell plate partitioning the cytoplasm of dividing cells. Cell plate formation is directed by orchestrated delivery, fusion of cytokinetic vesicles, and membrane maturation to form a nascent cell wall by timely deposition of polysaccharides. During cell plate maturation, the fragile membrane network transitions to a fenestrated sheet and finally a young cell wall. Here, we approximated cell plate sub-structures with testable shapes and adopted the Helfrich-free energy model for membranes, including a stabilizing and spreading force, to understand the transition from a vesicular network to a fenestrated sheet and mature cell plate. Regular cell plate development in the model was possible, with suitable bending modulus, for a two-dimensional late stage spreading force of 2-6 pN/nm, an osmotic pressure difference of 2-10 kPa, and spontaneous curvature between 0 and 0.04 nm(-1). With these conditions, stable membrane conformation sizes and morphologies emerged in concordance with stages of cell plate development. To reach a mature cell plate, our model required the late-stage onset of a spreading/stabilizing force coupled with a concurrent loss of spontaneous curvature. Absence of a spreading/stabilizing force predicts failure of maturation. The proposed model provides a framework to interrogate different players in late cytokinesis and potentially other membrane networks that undergo such transitions. Callose, is a polysaccharide that accumulates transiently during cell plate maturation. Callose-related observations were consistent with the proposed model's concept, suggesting that it is one of the factors involved in establishing the spreading force.

Automated summary

The late-stage onset of a spreading and stabilizing force is crucial for the development and maturation of plant cell plates. Researchers have used a model to study the process and found that a suitable spreading and stabilizing force is necessary for the formation and development of cell plates, and the absence of this force may lead to failure in cell plate maturation. Additionally, the findings suggest that callose may play a key role in establishing the spreading force.