The TPR2 corepressor forms condensates with repressors to fine-tune growth and development in rice

Transcriptional repression is a central mechanism regulating plant growth and development, yet how plant-specific corepressors achieve robust gene silencing remains unclear. Here, we identify the rice corepressor TPR2 (TOPLESS-RELATED 2) as a phase-separating protein that forms nuclear condensates through the cooperative action of an intrinsically disordered region (IDR1) and a plant-specific N-terminal tetramerization domain. Structure-guided mutagenesis disrupting tetramerization or deleting IDR1 markedly impaired condensate formation in vivo and in vitro. Complementation assays showed that only full-length TPR2, capable of robust condensate formation, rescued the growth defects of the tpr2 mutant, whereas phase separation-deficient variants failed to do so. Mechanistically, we demonstrate that TPR2 co-condenses with repressors such as D53 and IAA3 to facilitate histone deacetylation and establish repressive chromatin states in a phase separation-dependent manner, thereby fine-tuning key developmental genes. Together, these findings define a condensate-based mechanism for transcriptional repression in plants, linking corepressor phase separation to chromatin modification, gene silencing and developmental control.