Scientists Unlock the Secrets Behind Plant Cell Division

During division, cells copy and split DNA while breaking safely into two viable daughter cells, a process called cytokinesis. Yet the molecular basis of how plant cells accomplish this feat without mistakes has been unknown--until now. Scientists have uncovered the secrets behind plant cell division.

The cytokinesis process begins at the cell center, where the phragmoplast, a dynamic and complex structure, sends out tendrils toward opposite ends of the cell like a belt across its waist. These polymers, microtubules and actin filaments then travel toward the cell wall to a predetermined position. There, the cell plate forms. The new wall making the two new cells then takes shape along this pathway between the cell plates on opposite walls.

"How this process is directed and accomplished has been a mystery for a very long time," said Magdalena Bezanilla, one of the researchers, in a news release. "And we've known for a very long time that actin filaments are there in the structure, but nobody knew what they were for. What steers phragmoplast expansion at the molecular level was just not understood."

In order to better understand this process, the researchers used a microscope to watch key structures taking shape. The scientists labeled these structures and made videos of cytokinesis for hours to piece together how these structures accomplished their goal.

"Our new paper proposes a model showing how plant cells steer their cell division machinery into position and how actin contributes," said Bezanilla. "Our data from experiments in moss and tobacco provide evidence that a protein called myosin VIII, along with actin, guide cytokinesis. It answers what has been an open question in cell biology for decades."

The findings reveal how this process is accomplished in plants. It turns out that actin and actin-based molecular motors, the class VIII myosins, are key to the steering mechanism for cytokinesis in plants cells.

The findings are published in the journal eLife.