Auxin Influx Carriers Control Vascular Patterning and Xylem Differentiation in Arabidopsis thaliana
Fig 6
A model of apoplastic and cytoplasmic auxin control of xylem differentiation.
(A) Auxin cytoplasmic signaling is required for xylem differentiation [16,46,57–59]. Our computational analysis predicts apoplastic (extracellular) auxin as an inhibitor of this differentiation. Both efflux and influx carriers increase cytoplasmic auxin concentration at auxin maxima, while they antagonistically regulate apoplastic auxin concentration. Arrows stand for activation, while blunt arrows for inhibition. (B) Cytoplasmic (blue) and apoplastic (green) auxin concentrations in two cells (rectangles with rounded corners). Lighter blue and green account for decreased cytoplasmic and apoplastic concentrations respectively. The predicted differentiation phenotypes of WT, influx and efflux mutants are depicted on the right. Xylem differentiated cells are depicted with blue borders.