Memory in the wall: expanding our understanding of the roles of plant cell walls

The plant cell wall, while providing mechanical support to cells, also dynamically adjusts its composition and structure in response to cellular and environmental cues. Recent findings indicate that plants exposed to cold stress alter the composition of cell wall polysaccharides and that this altered status primes the plants to overcome future, more severe exposure. Here, we propose that the cell wall functions as a refined interface that retains information from past experiences, with such 'memory' being encoded as structural or compositional changes. This enables more efficient responses to future stimuli. Such a memory system may support various biological processes, in parallel with other systems such as chromatin-based epigenetic memory. The cell wall is uniquely capable of storing higher-order information related to the geometry of cells and tissues, mechanical cues, and environmental histories. In this context, we present emerging perspectives and representative cases of such memory stored in the plant cell wall, and we discuss plausible mechanisms through which the memory influences cellular responses.