Cytoplasmic Streaming in Plant Cells Emerges Naturally by Microfilament Self-Organization

TL;DR

This paper presents a model explaining how microfilament self-organization and hydrodynamics collaboratively lead to the emergence of cytoplasmic streaming patterns in plant cells, especially in Characean algae.

Contribution

It introduces a first-principles model combining motor dynamics and hydrodynamics to explain self-organized streaming pattern formation in plant cells.

Findings

Microfilament self-organization can generate streaming patterns.

Motor and hydrodynamic interactions reinforce pattern development.

The model explains observed streaming in Characeae and similar species.

Abstract

Many cells exhibit large-scale active circulation of their entire fluid contents, a process termed cytoplasmic streaming. This phenomenon is particularly prevalent in plant cells, often presenting strikingly regimented flow patterns. The driving mechanism in such cells is known: myosin-coated organelles entrain cytoplasm as they process along actin filament bundles fixed at the periphery. Still unknown, however, is the developmental process which constructs the well-ordered actin configurations required for coherent cell-scale flow. Previous experimental works on streaming regeneration in cells of Characean algae, whose longitudinal flow is perhaps the most regimented of all, hint at an autonomous process of microfilament self-organization driving the formation of streaming patterns during morphogenesis. Working from first principles, we propose a robust model of streaming emergence that combines motor dynamics with both micro- and macroscopic hydrodynamics to explain how several independent processes, each ineffectual on its own, can reinforce to ultimately develop the patterns of streaming observed in the Characeae and other streaming species.