Fig. 7: Model of the PuRBOHF-mediated reactive oxygen species (ROS) signaling pathway involved in stone cell lignification in pear fruit.

PuRBOHF, controlled by PuMYB169, enhances the ROS burst in the plasma membrane. ROS then serve as secondary messengers and induce the transcription of PuPOD2 and PuLAC2, ultimately promoting monolignol polymerization and stone cell formation. In addition, apoplastic ROS are necessary for the oxidative polymerization of monolignols to lignin