TY  - JOUR
A1  - Robert, Helene S.
A1  - Grunewald, Wim
A1  - Sauer, Michael
A1  - Cannoot, Bernard
A1  - Soriano, Mercedes
A1  - Swarup, Ranjan
A1  - Weijers, Dolf
A1  - Bennett, Malcolm
A1  - Boutilier, Kim
A1  - Friml, Jiri
T1  - Plant embryogenesis requires AUX/LAX-mediated auxin influx
JF  - Development : Company of Biologists
N2  - The plant hormone auxin and its directional transport are known to play a crucial role in defining the embryonic axis and subsequent development of the body plan. Although the role of PIN auxin efflux transporters has been clearly assigned during embryonic shoot and root specification, the role of the auxin influx carriers AUX1 and LIKE-AUX1 (LAX) proteins is not well established. Here, we used chemical and genetic tools on Brassica napus microspore-derived embryos and Arabidopsis thaliana zygotic embryos, and demonstrate that AUX1, LAX1 and LAX2 are required for both shoot and root pole formation, in concert with PIN efflux carriers. Furthermore, we uncovered a positive-feedback loop between MONOPTEROS-(ARF5)dependent auxin signalling and auxin transport. This MONOPTEROS dependent transcriptional regulation of auxin influx (AUX1, LAX1 and LAX2) and auxin efflux (PIN1 and PIN4) carriers by MONOPTEROS helps to maintain proper auxin transport to the root tip. These results indicate that auxin-dependent cell specification during embryo development requires balanced auxin transport involving both influx and efflux mechanisms, and that this transport is maintained by a positive transcriptional feedback on auxin signalling.
KW  - Arabidopsis thaliana embryogenesis
KW  - Auxin transport
KW  - AUX1
KW  - LIKE-AUX1 (LAX)
KW  - MONOPTEROS (ARF5)
KW  - PIN
KW  - Brassica napus
KW  - Microspore
Y1  - 2015
U6  - https://doi.org/10.1242/dev.115832
SN  - 0950-1991
SN  - 1477-9129
VL  - 142
IS  - 4
SP  - 702
EP  - 711
PB  - Company of Biologists Limited
CY  - Cambridge
ER  -