Plant development is regulated by a family of auxin receptor F box proteins.
The plant hormone auxin has been implicated in virtually every aspect of plant growth and development. Auxin acts by promoting the degradation of transcriptional regulators called Aux/IAA proteins. Aux/IAA degradation requires TIR1, an F box protein that has been shown to function as an auxin receptor. However, loss of TIR1 has a modest effect on auxin response and plant development. Here we show that three additional F box proteins, called AFB1, 2, and 3, also regulate auxin response. Like TIR1, these proteins interact with the Aux/IAA proteins in an auxin-dependent manner. Plants that are deficient in all four proteins are auxin insensitive and exhibit a severe embryonic phenotype similar to the mp/arf5 and bdl/iaa12 mutants. Correspondingly, all TIR1/AFB proteins interact with BDL, and BDL is stabilized in triple mutant plants. Our results indicate that TIR1 and the AFB proteins collectively mediate auxin responses throughout plant development.
Department of Biology, Indiana University, Bloomington, Indiana 47405, USA.
Nihal
N
Dharmasiri
Sunethra
S
Dharmasiri
Dolf
D
Weijers
Esther
E
Lechner
Masashi
M
Yamada
Lawrence
L
Hobbie
Jasmin S
JS
Ehrismann
Gerd
G
Jürgens
Mark
M
Estelle
D017360:Arabidopsis / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D044783:F-Box Proteins / Q000235:genetics / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; D044783:F-Box Proteins; D007210:Indoleacetic Acids; D010940:Plant Proteins; D011956:Receptors, Cell Surface; C501405:TIR1 protein, Arabidopsis; D014157:Transcription Factors; C046131:auxin receptor, plant