Decoding light perception and fine-tuning photomorphogenesis through post-translational modifications

Post-translational modifications (PTMs) are a widespread regulatory strategy that fine-tunes protein stability, activity, interactions, and localisation. This mechanism acts as a critical molecular switch that enables plants to precisely decode the quality, quantity, and duration of light. It integrates these environmental light cues with intrinsic signalling networks to coordinate downstream physiological responses. In this review, we examine the emerging evidence that post-translational modifications (PTMs) dynamically regulate key components of light signalling during seedling development. We highlight how dynamic PTM networks enable rapid, reversible, and context-specific control of protein function, ensuring adaptive growth under different light conditions. We further discuss additional regulatory layers, underscoring the need to investigate transient, combinatorial PTMs and their mechanistic interplay. Finally, we also speculate that proteome-wide PTM mapping, advanced proteomic approaches, and leveraging artificial intelligence and machine learning will be instrumental in fully harnessing the potential of PTMs to enhance plant growth and resilience.