Knowing what your neighbour is doing
Plant cells are connected to each other via their cell wall. While growing, it is therefore useful that they know what their neighbouring cells are doing. Now researchers show in Nature Plants how plants perceive changes of their neighbours: though holding on to them.
When plant cells don’t react to the growth of their neighbours, then their cells, and through them their organs can turn into strange shapes. All because the cells are connected. This might be awkward, but it also gives plants their rigidity. The fact that plants coordinate their growth with their neighbouring cells suggest that the cells can perceive changes in their cell wall. This the researchers decided to study in more detail.
The first thing they did was analyse which proteins were located at the edges of the cell. Using RAB-A5c, which brings other proteins to the edges of the cell, as a bait the researchers caught a whole lot of proteins that bind to RAN-A5c. Two often caught proteins were RLP4 and RLP4-L1.
RLP4 and RLP4-L1 perceive changes in neighbouring cell growth
Subsequently the researchers checked if these proteins are indeed located at the edges of the cell. This they did through attaching a fluorescence tag to these proteins. Using this the researchers observed that these proteins are located at the cell edges.
This was followed by analysing what these proteins are doing at the cell edges. The noticed that RLP4 and RLP4-L1 hold on to structures of the cell wall. At the moment these proteins are no longer holding on to the cell wall, the proteins disappeared from the edges. Like after the researchers removed the neighbouring cells.
Using RLP4 and RLP4-L1 plant cells perceive changes in the cell wall. Because they share their cell wall with their neighbours, changes in the cell wall are a proxy for changes in growth of their neighbouring cells. When those is no longer synchronized with their own growth, then it is time for action.
Literature
Elliott, L., Kalde, M., Schürholz, AK. et al. (2024) A self-regulatory cell-wall-sensing module at cell edges controls plant growth. Nat. Plants. https://doi.org/10.1038/s41477-024-01629-8
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