Root system architecture from coupling cell shape to auxin transport.
Lateral organ position along roots and shoots largely determines plant architecture, and depends on auxin distribution patterns. Determination of the underlying patterning mechanisms has hitherto been complicated because they operate during growth and division. Here, we show by experiments and computational modeling that curvature of the Arabidopsis root influences cell sizes, which, together with tissue properties that determine auxin transport, induces higher auxin levels in the pericycle cells on the outside of the curve. The abundance and position of the auxin transporters restricts this response to the zone competent for lateral root formation. The auxin import facilitator, AUX1, is up-regulated by auxin, resulting in additional local auxin import, thus creating a new auxin maximum that triggers organ formation. Longitudinal spacing of lateral roots is modulated by PIN proteins that promote auxin efflux, and pin2,3,7 triple mutants show impaired lateral inhibition. Thus, lateral root patterning combines a trigger, such as cell size difference due to bending, with a self-organizing system that mediates alterations in auxin transport.
Laskowski
Marta
M
Department of Biology, Oberlin College, Oberlin, Ohio, USA.
Grieneisen
Verônica A
VA
Hofhuis
Hugo
H
Hove
Colette A Ten
CA
Hogeweg
Paulien
P
Marée
Athanasius F M
AF
Scheres
Ben
B
D017360:Arabidopsis; D029681:Arabidopsis Proteins / Q000378:metabolism; D002454:Cell Differentiation; D019295:Computational Biology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D007210:Indoleacetic Acids / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism; D008954:Models, Biological; D018517:Plant Roots / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism
C100794:AUX1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins