STY1 regulates auxin homeostasis and affects apical-basal patterning of the Arabidopsis gynoecium.
Gynoecia of the Arabidopsis mutant sty1-1 display abnormal style morphology and altered vascular patterning. These phenotypes, which are enhanced in the sty1-1 sty2-1 double mutant, suggest that auxin homeostasis or signalling might be affected by mutations in STY1 and STY2, both members of the SHI gene family. Chemical inhibition of polar auxin transport (PAT) severely affects the apical-basal patterning of the gynoecium, as do mutations in the auxin transport/signalling genes PIN1, PID and ETT. Here we show that the apical-basal patterning of sty1-1 and sty1-1 sty2-1 gynoecia is hypersensitive to reductions in PAT, and that sty1-1 enhances the PAT inhibition-like phenotypes of pin1-5, pid-8 and ett-1 gynoecia. Furthermore, we show that STY1 activates transcription of the flavin monooxygenase-encoding gene THREAD/YUCCA4, involved in auxin biosynthesis, and that changes in expression of STY1 and related genes lead to altered auxin homeostasis. Our results suggest that STY1 and related genes promote normal development of the style and affect apical-basal patterning of the gynoecium through regulation of auxin homeostasis.
Sohlberg
Joel J
JJ
Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, Box 7080, S-750 07 Uppsala, Sweden.
Myrenås
Mattias
M
Kuusk
Sandra
S
Lagercrantz
Ulf
U
Kowalczyk
Mariusz
M
Sandberg
Göran
G
Sundberg
Eva
E
D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D019521:Body Patterning / Q000502:physiology; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics; D035264:Flowers / Q000254:growth & development* / Q000648:ultrastructure; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D006706:Homeostasis / Q000502:physiology; D007210:Indoleacetic Acids / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics; D010797:Phthalimides; D017346:Protein Serine-Threonine Kinases / Q000235:genetics
D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C109765:ETT protein, Arabidopsis; D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins; D009687:Nuclear Proteins; C116363:PIN1 protein, Arabidopsis; D010797:Phthalimides; C513747:STY1 protein, Arabidopsis; C513748:STY2 protein, Arabidopsis; C002687:alpha-naphthylphthalamic acid; C405165:PINOID protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases