--- res: bibo_abstract: - 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.@eng bibo_authorlist: - foaf_Person: foaf_givenName: Hélène foaf_name: Robert, Hélène foaf_surname: Robert - foaf_Person: foaf_givenName: Wim foaf_name: Grunewald, Wim foaf_surname: Grunewald - foaf_Person: foaf_givenName: Michael foaf_name: Sauer, Michael foaf_surname: Sauer - foaf_Person: foaf_givenName: Bernard foaf_name: Cannoot, Bernard foaf_surname: Cannoot - foaf_Person: foaf_givenName: Mercedes foaf_name: Soriano, Mercedes foaf_surname: Soriano - foaf_Person: foaf_givenName: Ranjan foaf_name: Swarup, Ranjan foaf_surname: Swarup - foaf_Person: foaf_givenName: Dolf foaf_name: Weijers, Dolf foaf_surname: Weijers - foaf_Person: foaf_givenName: Malcolm foaf_name: Bennett, Malcolm foaf_surname: Bennett - foaf_Person: foaf_givenName: Kim foaf_name: Boutilier, Kim foaf_surname: Boutilier - foaf_Person: foaf_givenName: Jirí foaf_name: Friml, Jirí foaf_surname: Friml foaf_workInfoHomepage: http://www.librecat.org/personId=4159519E-F248-11E8-B48F-1D18A9856A87 orcid: 0000-0002-8302-7596 bibo_doi: 10.1242/dev.115832 bibo_issue: '4' bibo_volume: 142 dct_date: 2015^xs_gYear dct_language: eng dct_publisher: Company of Biologists@ dct_title: Plant embryogenesis requires AUX/LAX-mediated auxin influx@ ...