Extended Data Fig. 7: PIN1-mediated polar auxin transport constrains auxin-induced gene expression laterally.
From: Specification of leaf dorsiventrality via a prepatterned binary readout of a uniform auxin input
a–d, Time-lapse series of representative p-1 leaf primordia without or with application of 100 µM NPA at 0 h (a, c) shows perturbation of PIN1-mediated polar auxin transport does not block the shift in auxin-induced gene expression (DR5v2) from the adaxial side at p-1 (0 h) to the middle domain 72 h later. Instead, in comparison to mock-treated primordia (b), NPA-treated primordia are wider and show a lateral expansion of the DR5v2 expression domain (arrows) (d). (a, c) Optical longitudinal sections and (b, d) top views of select leaf primordia. e-f, Wild type (e) and pin1 mutant (f) shoot apices showing pin1 leaf primordia are comparatively wider and occasionally laterally fused (arrow). Note also the irregular phyllotaxy of pin1 apices (f). Cell walls were stained by PI. Asterisks, meristem centre; p, leaf primordium. Scale bars, 20 µm (a–d), 50 µm (e-f). Representative data from n = 6 primordia per treatment (a–d), and n = 12 apices per line (e-f) is shown.
