Fig. 1.

Schematic illustration of the experimental strategy. (A) Normal secondary cell wall is deposited in fiber cells of the inflorescence stem and the whole regulatory network is activated in the wild-type plant. (B) The nst1-1 nst3-1 double mutant lacks a secondary cell wall in fiber cells and the entire regulatory network is inactivated. Introduction of chimeric activator functioning downstream of NSTs or out of the cascade driven by the NST3 promoter into the nst1-1 nst3-1 double mutant could reconstitute a transmuted secondary cell wall by partially activating the regulatory network.