Biomolecular condensates in plant stress and development: recent advances and emerging concepts.

Biomolecular condensates have emerged as a central paradigm for understanding how plant cells organize biochemical processes without membrane boundaries, particularly under fluctuating environmental conditions. In plants, many condensates are thought to form through liquid-liquid phase separation, enabling selective concentration of proteins and RNAs into dynamic assemblies. This organization helps buffer stress, protect macromolecules, and reprogram gene expression. Here, we synthesize current knowledge of condensate functions in plant development and stress responses, focusing on Arabidopsis thaliana, where mechanistic insights are most advanced. We first outline the biophysical principles underlying condensate formation, emphasizing multivalent protein-protein and protein-RNA interactions, intrinsically disordered regions, and prion-like or low-complexity domains. We then discuss condensates in plant development, highlighting hydration-associated assemblies in seeds, as well as condensation-based regulation of light signaling, auxin pathways, and flowering time. Next, we examine condensates involved in stress adaptation, including stress granules, processing bodies, nuclear assemblies, and chloroplast condensates. Finally, we review the experimental toolkits used to study condensates in plants, including live-cell imaging and fluorescence recovery after photobleaching, in vitro reconstitution, proximity labeling, particle enrichment strategies, and RNA-centric profiling approaches, and discuss technical considerations and limitations. We conclude by outlining key open questions regarding condensate regulation, proteostasis, organelle function, and plant resilience under climate change.