Flexible cell walls
Plant cells use the pressure from their neighbours to find out how those neighbours are faring. Now a group of international scientists show in Developmental Cell that flexibility of the cells own cell wall determines the subsequent response.
Plant cells check the constantly how their neighbours are doing. They are questioning themselves: Is the pressure that I experience changed? Is my shape changed? When one of those questions is answered with a ‘yes’ then the cell gears into action. But how the cell this does is not completely clear.
To get more insight into this the researchers investigated how the flexibility of the cell wall influences cell division after wounding. The first thing the researchers did was analyse the flexibility of root cells. Discovering that cells deeper in the root have a more flexible cell wall than cells that are located closer to the outside of the root.
Cell wall flexibility is enables replacement of damaged cells
After having discovered this natural difference, the researchers studied whet happens when a neighbouring cell is wounded. The noticed that when cells get damaged, they give their neighbouring cells a nudge. But only when those neighbouring cells have a flexible cell wall. And only then did those cells divide in such a way that one of their daughter cells occupies the space of the damaged cell.
Subsequently the researchers analysed the cell wall of different cells. Discovering that flexible cell walls have a different pectin composition than non-flexible cell walls. In addition, some other cell wall mutants suggest that the hormone ethylene might affect cell wall flexibility.
This the researchers confirmed by damaging roots in the presence of extra ethylene. The cell wall of these roots is less flexible, the damaged cells could not nudge their neighbours. Cell division also did not occur.
For a plant cell wall flexibility is important so it can replace damaged cells. Preventing the occurrence of holes, for example, when a nematode damages a cell. This is important to know, because cell wall composition also has a role in preventing damages in the first place. This study shows that not only a strong, but also a flexible cell wall is of great importance for a plant.
Literature
Di Fino et al., Cellular damage triggers mechano-chemical control of cell wall dynamics and patterned cell divisions in plant healing, Developmental Cell (2024), https://doi.org/10.1016/j.devcel.2024.12.032
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