Epigenetic regulation of fruit shape determination by the JAGGED gene in Capsella rubella.

Fruits are a key feature defining angiosperms, yet how local growth is coordinated during development to generate diverse fruits remains unclear. Here, we demonstrate that the Capsella rubella C2H2-zinc finger transcription factor JAGGED (CrJAG) controls fruit shape determination by promoting both cell division and anisotropic growth. At the molecular level, CrJAG physically interacts with members of the Capsella rubella MULTICOPY SUPPRESSOR OF IRA1 (CrMSI)  histone chaperone family, increasing the chromatin accessibility and thereby sustaining the expression of genes involved in fruit morphogenesis. The resulting closed chromatin state in Crjag fruits is characterized by a reduction of the active histone marker (H3K18ac) and an increase of the repressive marker (H3K27me3). Further expression and pharmacological treatment analyses indicate that the developmental defects in Crjag fruits are largely attributable to down-regulation of the key cell-cycle regulator CrAUR2. Collectively, our findings therefore suggest that fine-tuning the cell cycle via epigenetic modification represents an additional, essential layer of regulation critical to organ development and diversification.