Regulation of phyllotaxis by polar auxin transport.
The regular arrangement of leaves around a plant's stem, called phyllotaxis, has for centuries attracted the attention of philosophers, mathematicians and natural scientists; however, to date, studies of phyllotaxis have been largely theoretical. Leaves and flowers are formed from the shoot apical meristem, triggered by the plant hormone auxin. Auxin is transported through plant tissues by specific cellular influx and efflux carrier proteins. Here we show that proteins involved in auxin transport regulate phyllotaxis. Our data indicate that auxin is transported upwards into the meristem through the epidermis and the outermost meristem cell layer. Existing leaf primordia act as sinks, redistributing auxin and creating its heterogeneous distribution in the meristem. Auxin accumulation occurs only at certain minimal distances from existing primordia, defining the position of future primordia. This model for phyllotaxis accounts for its reiterative nature, as well as its regularity and stability.
Reinhardt
Didier
D
Institute of Plant Sciences, University of Bern, Switzerland.
Pesce
Eva-Rachele
ER
Stieger
Pia
P
Mandel
Therese
T
Baltensperger
Kurt
K
Bennett
Malcolm
M
Traas
Jan
J
Friml
Jirí
J
Kuhlemeier
Cris
C
D017360:Arabidopsis / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D001692:Biological Transport; D019521:Body Patterning; D035264:Flowers / Q000254:growth & development / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins; D018519:Meristem / Q000378:metabolism; D009154:Mutation; D038081:Organogenesis; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
C100794:AUX1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C116363:PIN1 protein, Arabidopsis; D012333:RNA, Messenger