Identification and comprehensive characterization of the OVATE family protein in litchi.

Fruit shape is a commercially important trait in litchi, yet the genetic mechanisms that regulate its development remain largely unresolved. OVATE Family Proteins (OFPs) are plant-specific transcriptional regulators known to play key roles in fruit morphology, organ growth, and overall plant development. In this study, we identified 14 OFP genes distributed across eight chromosomes in the litchi genome. Phylogenetic reconstruction and conserved motif analyses demonstrated that all LcOFPs contain the characteristic OVATE domain and can be grouped into three subfamilies based on motif composition. Promoter cis-element analysis further suggested that LcOFPs may respond to diverse phytohormone signals and abiotic stresses, indicating their involvement in multiple regulatory pathways. Integrated RNA-seq and RT-qPCR analyses revealed that LcOFP3, LcOFP6, LcOFP10, LcOFP13, and LcOFP14 show tissue-specific expression patterns and dynamic transcriptional changes during fruit development in two cultivars with contrasting fruit sizes. Heterologous overexpression of LcOFP3 significantly modified fruit morphology in tomato. These findings clarify the genetic mechanisms through which OFP genes regulate fruit shape in litchi and highlight promising genetic targets for future litchi breeding and improvement.