The auxin-responsive transcription factor SlDOF9 regulates inflorescence and flower development in tomato

Understanding the mechanisms underlying differentiation of inflorescence and flower meristems is essential towards enlarging our knowledge of reproductive organ formation and to open new prospects for improving yield traits. Here, we show that SlDOF9 is a new modulator of floral differentiation in tomato. CRISPR/Cas9 knockout strategy uncovered the role of SlDOF9 in controlling inflorescence meristem and floral meristem differentiation via the regulation of cell division genes and inflorescence architecture regulator LIN. Tomato dof9-KO lines have more flowers in both determinate and indeterminate cultivars and produce more fruit upon vibration-assisted fertilization. SlDOF9 regulates inflorescence development through an auxin-dependent ARF5-DOF9 module that seems to operate, at least in part, differently in Arabidopsis and tomato. Our findings add a new actor to the complex mechanisms underlying reproductive organ differentiation in flowering plants and provide leads towards addressing the diversity of factors controlling the transition to reproductive organs. In tomato, the transcription factor DOF9 regulates inflorescence termination and flower development, which determines fruit yield. DOF9 is connected to the auxin signalling pathway through ARF5.

Automated summary

This study identifies a new regulator, SlDOF9, that controls floral differentiation in tomato by regulating cell division genes and inflorescence architecture regulator LIN. Knockout of SlDOF9 in tomato leads to an increase in the number of flowers and fruit yield.