Figure 7. Mathematical Modeling of Trichome Patterning by Depletion of TTG1.
(A) Interaction scheme. TTG1 is ubiquitously expressed at rate α1 (magenta arrow), degraded at rate λ1 (red arrow), and nondirectionally transported between cells at rate d (green arrow). It forms an AC with GL3 at rate β (blue arrows). The AC induces the expression of GL3 at rate α2 (brown arrow). GL3 and AC are degraded at rates λ2 and λ3, respectively.
(B) Typical concentration pattern of total TTG1 (i.e., TTG1 + AC). Model parameters were estimated as explained in the Materials and Methods section. Light color indicates high concentration. Levels are normalized by the maximal concentration found in trichomes, which are indicated by white. A substantial amount of TTG1 is found in trichomes while it is depleted in neighboring cells.
(C) Dependence of trichome density on parameters related to TTG1 function (color code as in (A); α1, star; α2, plus; β, diamond; λ1, triangle; λ3, circle; d, square). Parameters are changed in a range from 10% to 1000% of their estimated values. Blunt ends denote the loss of trichome patterning. Inset: Corresponding change of the percentage of trichome found in clusters.