Abstract

Mechanical stresses arising in growing tissues are key regulators of morphogenesis. This is especially true in plants where the cell wall assembly constitutes the main load-bearing structure. Its mechanical sollicitation, due to internal cell turgor, triggers two main antagonist responses: wall stiffening and cell expansion. From asystematic perspective, these two mechanisms constitute an incoherent feedforward loop. Within biochemical regulatory networks, such motifs may act as oriented triggers or pulse generators. However,their involvement in mechano-sensitive pathways is less common and understood. What are the properties of mechano-sensitive incoherent feedforward loop (ms-IFFL)? To what extent are plant morphodynamics influenced by them? The simple shape and “russian doll” organization of the Arabidopsis thaliana seed offer unique conditions toaddress these questions. From quantitative experiments we derived a 1D “toy model“ to investigate the ms-IFFL properties. This model accounts for seed morphodynamics in wild-type and mutant populations and sheds new light on the counter-intuitive role of pressure in growing plant tissues.