Robert, Hélène; Grunewald, Wim; Sauer, Michael; Cannoot, Bernard; Soriano, Mercedes; Swarup, Ranjan; Weijers, Dolf; Bennett, Malcolm; Boutilier, Kim; Friml, JiríIST Austria
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 betweenMONOPTEROS(ARF5)-dependent auxin signalling and auxin transport. ThisMONOPTEROSdependent 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.
W.G. is a post-doctoral fellow of the Research Foundation Flanders. H.S.R. is supported by Employment of Best Young Scientists for International Cooperation Empowerment [CZ.1.07/2.3.00/30.0037], co-financed by the European Social Fund and the state budget of the Czech Republic. Mi.S. was funded by the Ramón y Cajal program. This work was supported by the European Research Council [project ERC-2011-StG-20101109-PSDP], project ‘CEITEC – Central European Institute of Technology’ [CZ.1.05/1.1.00/02.0068], the European Social Fund [CZ.1.07/2.3.00/20.0043] and the Czech Science Foundation GACR [GA13-40637S] to J.F. We acknowledge funding from the Biological and Biotechnological Science Research Council (BBSRC) and Engineering Physics Science Research Council (EPSRC) to R.S. and M.B
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Robert H, Grunewald W, Sauer M, et al. Plant embryogenesis requires AUX/LAX-mediated auxin influx. Development. 2015;142(4):702-711. doi:10.1242/dev.115832
Robert, H., Grunewald, W., Sauer, M., Cannoot, B., Soriano, M., Swarup, R., … Friml, J. (2015). Plant embryogenesis requires AUX/LAX-mediated auxin influx. Development. Company of Biologists. https://doi.org/10.1242/dev.115832
Robert, Hélène, Wim Grunewald, Michael Sauer, Bernard Cannoot, Mercedes Soriano, Ranjan Swarup, Dolf Weijers, Malcolm Bennett, Kim Boutilier, and Jiří Friml. “Plant Embryogenesis Requires AUX/LAX-Mediated Auxin Influx.” Development. Company of Biologists, 2015. https://doi.org/10.1242/dev.115832.
H. Robert et al., “Plant embryogenesis requires AUX/LAX-mediated auxin influx,” Development, vol. 142, no. 4. Company of Biologists, pp. 702–711, 2015.
Robert H, Grunewald W, Sauer M, Cannoot B, Soriano M, Swarup R, Weijers D, Bennett M, Boutilier K, Friml J. 2015. Plant embryogenesis requires AUX/LAX-mediated auxin influx. Development. 142(4), 702–711.
Robert, Hélène, et al. “Plant Embryogenesis Requires AUX/LAX-Mediated Auxin Influx.” Development, vol. 142, no. 4, Company of Biologists, 2015, pp. 702–11, doi:10.1242/dev.115832.