title: AUX/LAX genes encode a family of auxin influx transporters that perform distinct functions during Arabidopsis development.
abstract: Auxin transport, which is mediated by specialized influx and efflux carriers, plays a major role in many aspects of plant growth and development. AUXIN1 (AUX1) has been demonstrated to encode a high-affinity auxin influx carrier. In Arabidopsis thaliana, AUX1 belongs to a small multigene family comprising four highly conserved genes (i.e., AUX1 and LIKE AUX1 [LAX] genes LAX1, LAX2, and LAX3). We report that all four members of this AUX/LAX family display auxin uptake functions. Despite the conservation of their biochemical function, AUX1, LAX1, and LAX3 have been described to regulate distinct auxin-dependent developmental processes. Here, we report that LAX2 regulates vascular patterning in cotyledons. We also describe how regulatory and coding sequences of AUX/LAX genes have undergone subfunctionalization based on their distinct patterns of spatial expression and the inability of LAX sequences to rescue aux1 mutant phenotypes, respectively. Despite their high sequence similarity at the protein level, transgenic studies reveal that LAX proteins are not correctly targeted in the AUX1 expression domain. Domain swapping studies suggest that the N-terminal half of AUX1 is essential for correct LAX localization. We conclude that Arabidopsis AUX/LAX genes encode a family of auxin influx transporters that perform distinct developmental functions and have evolved distinct regulatory mechanisms.
authors: School of Biosciences and Centre for Plant Integrative Biology, University of Nottingham, LE12 5RD Nottingham, United Kingdom.
authors: Benjamin
authors: B
authors: Péret
authors: Kamal
authors: K
authors: Swarup
authors: Alison
authors: A
authors: Ferguson
authors: Malvika
authors: M
authors: Seth
authors: Yaodong
authors: Y
authors: Yang
authors: Stijn
authors: S
authors: Dhondt
authors: Nicholas
authors: N
authors: James
authors: Ilda
authors: I
authors: Casimiro
authors: Paula
authors: P
authors: Perry
authors: Adnan
authors: A
authors: Syed
authors: Haibing
authors: H
authors: Yang
authors: Jesica
authors: J
authors: Reemmer
authors: Edward
authors: E
authors: Venison
authors: Caroline
authors: C
authors: Howells
authors: Miguel A
authors: MA
authors: Perez-Amador
authors: Jeonga
authors: J
authors: Yun
authors: Jose
authors: J
authors: Alonso
authors: Gerrit T S
authors: GT
authors: Beemster
authors: Laurent
authors: L
authors: Laplaze
authors: Angus
authors: A
authors: Murphy
authors: Malcolm J
authors: MJ
authors: Bennett
authors: Erik
authors: E
authors: Nielsen
authors: Ranjan
authors: R
authors: Swarup
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D019521:Body Patterning; D018548:Cotyledon / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D055786:Gene Knockout Techniques; D007210:Indoleacetic Acids / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D005810:Multigene Family; D016254:Mutagenesis, Insertional; D010641:Phenotype; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D058526:Plant Vascular Bundle / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D030821:Plants, Genetically Modified; D036226:Seedlings / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism
chemical_list: C100794:AUX1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; C578308:LAX1 protein, Arabidopsis; C578309:LAX2 protein, Arabidopsis; C531125:LAX3 protein, Arabidopsis; D026901:Membrane Transport Proteins