The auxin influx carrier LAX3 promotes lateral root emergence

Kamal Swarup*, Eva Benková*, Ranjan Swarup*, Ilda Casimiro*, Benjamin Péret, Yaodong Yang, Geraint Parry, Erik Nielsen, Ive De Smet, Steffen Vanneste, Mitch P. Levesque, David Carrier, Nicholas James, Vanessa Calvo, Karin Ljung, Eric Kramer, Rebecca Roberts, Neil Graham, Sylvestre Marillonnet, Kanu Patel, Jonathan D.G. Jones, Christopher G. Taylor, Daniel P. Schachtman, Sean May, Goran Sandberg, Philip Benfey, Jiri Friml, Ian Kerr, Tom Beeckman, Laurent Laplaze & Malcolm J. Bennett

Lateral roots originate deep within the parental root from a small number of founder cells at the periphery of vascular tissues and must emerge through intervening layers of tissues. We describe how the hormone auxin, which originates from the developing lateral root, acts as a local inductive signal which re-programmes adjacent cells. Auxin induces the expression of a previously uncharacterized auxin influx carrier LAX3 in cortical and epidermal cells directly overlaying new primordia. Increased LAX3 activity reinforces the auxin-dependent induction of a selection of cell-wall-remodelling enzymes, which are likely to promote cell separation in advance of developing lateral root primordia.

Nature Cell Biology 10 (8), 946-954

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