The asymmetry engine: how plants harness asymmetries to shape their bodies.

Plant development depends on growth asymmetry to establish body plans and adapt to environmental stimuli. We explore how plants initiate, propagate, and regulate organ-wide growth asymmetries. External cues, such as light and gravity, and internal signals, including stochastic cellular growth variability, drive these asymmetries. The plant hormone auxin orchestrates growth asymmetry through its distribution and transport. Mechanochemical feedback loops, exemplified by apical hook formation, further amplify growth asymmetries, illustrating the dynamic interplay between biochemical signals and physical forces. Growth asymmetry itself can serve as a continuous cue, influencing subsequent growth decisions. By examining specific cellular programs and their responses to asymmetric cues, we propose that the decision to either amplify or dampen these asymmetries is key to shaping plant organs.