Tissue layer specific regulation of leaf length and width in Arabidopsis as revealed by the cell autonomous action of ANGUSTIFOLIA.
In vascular plants the shoot apical meristem consists of three tissue layers, L1, L2 and the L3, that are kept separate during organ formation and give rise to the epidermis (L1) and the subepidermal tissues (L2, L3). For proper organ development these different tissue layers must interact with each other, though their relative contributions are a matter of debate. Here we use ANGUSTIFOLIA (AN), which controls cell polarity and leaf shape, to study its morphogenetic function in the epidermis and the subepidermis of Arabidopsis thaliana. We show that ANGUSTIFOLIA expression in the subepidermis cannot rescue epidermal cell polarity defects, indicating a cell-autonomous molecular function. We demonstrate that leaf width is only rescued by subepidermal AN expression, whereas leaf length is also rescued by epidermal expression. Strikingly, subepidermal rescue of leaf width is accompanied by increased cell number in the epidermis, indicating that AN can trigger cell divisions in a non-autonomous manner.
Botanical Institute III, University of Köln, Gyrhofstrasse 15, 50931 Köln, Germany.
Yang
Y
Bai
Stefanie
S
Falk
Arp
A
Schnittger
Marc J
MJ
Jakoby
Martin
M
Hülskamp
D017360:Arabidopsis / Q000166:cytology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D002455:Cell Division; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D018519:Meristem / Q000166:cytology / Q000235:genetics; D009154:Mutation; D019441:Plant Epidermis / Q000166:cytology / Q000235:genetics; D018515:Plant Leaves / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D030821:Plants, Genetically Modified; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction
D029681:Arabidopsis Proteins; D049452:Green Fluorescent Proteins; D012097:Repressor Proteins; C452846:DETORQEO protein, Arabidopsis