A force of nature: Molecular mechanisms of mechanoperception in plants

The ability to sense and respond to a wide variety of mechanical stimuli - gravity, touch, osmotic pressure, or the resistance of the cell wall - is a critical feature of every plant cell, whether or not it is specialized for mechanotrans-duction. Mechanoperceptive events are an essential part of plant life, required for normal growth and development at the cell, tissue, and whole-plant level and for the proper response to an array of biotic and abiotic stresses. One current challenge for plant mechanobiologists is to link these physiological responses to specific mechanoreceptors and signal transduction pathways. Here, we describe recent progress in the identification and characterization of two classes of putative mechanoreceptors, ion channels and receptor-like kinases. We also discuss how the secondary messenger Ca ²⁺ operates at the centre of many of these mechanical signal transduction pathways.