The Zinc Finger protein SlZFP2 is essential for tomato fruit locular tissue morphogenesis

In tomato (Solanum lycopersicum L.) fruit, the locular tissue (LT) is a unique jelly-like tissue that differentiates from the central axis of the fruit after ovule fertilization. LT is essential for seed development and dispersal by preventing early germination and initiating fruit ripening. In this work, we studied a "gel-less" mutant and identified the underlying mutation in the coding sequence of the C2H2 zinc finger transcription factor (TF) SlZFP2. Histological, cytological and molecular characterization from knockout-CRISPR/Cas9 lines for this gene revealed the strong and early impact of zfp2 mutation on cell cycle and endocycle in LT. Additionally, model-based analysis of cellular data revealed that cell cycle was the main altered process, explaining the zfp2 mutant phenotype. Further laser capture microdissection coupled with RNA-Seq analysis of young LT highlighted global expression changes between WT and zfp2 mutant and led to a preliminary list of potential direct targets of the SlZFP2 TF. This multifaceted approach not only uncovered a new role for SlZFP2 TF as an essential regulator of LT morphogenesis, but also provides a foundation for future works aimed at deciphering the intricate regulatory networks governing fruit tissue development in tomato. One sentence summaryAlteration of cell division and endoreduplication in a gel-less mutant reveals the role of the transcription factor SlZFP2 in tomato locular tissue morphogenesis