Polar auxin transport modulates early leaf flattening

The biomechanical and biochemical processes that result into this bizarre shape are subject of study. Already several decades ago scientists like Ian Sussex have demonstrated through microsurgical ablation that communication between the shoot apical meristem and the leaf primordium is necessary to achieve the correct leaf shape. How microsurgeries interact with polarity genes remains elusive, but the phytohormone auxin seems to play a pivotal role.

PlantDynamics Lab (Wabnik group @PlantDynamics) and Yuling Jiao team (IGDB, Pekín) in the frame of the CEPEI international collaboration, combined live-imaging and computer model simulations to show that an oval-shaped auxin response in inner cells of leaf primordium is essential for the formation of initial bilateralism in leaf primordia. Additionally, our computer simulations suggest that local auxin biosynthesis in early leaf primordia could remove necessity for external auxin supply originating from the meristem, potentially explaining differences between Arabidopsis and Solanum species.