Arabidopsis interdigitating cell growth requires two antagonistic pathways with opposing action on cell morphogenesis.
Coordinating growth and communication between adjacent cells is a critical yet poorly understood aspect of tissue development and organ morphogenesis. We report a Rho GTPase signaling network underlying the jigsaw puzzle appearance of Arabidopsis leaf pavement cells, in which localized outgrowth in one cell is coordinated with localized inhibition of outgrowth of the adjacent cell to form interdigitating lobes and indentations. Locally activated ROP2, a Rho-related GTPase from plants, activates RIC4 to promote the assembly of cortical actin microfilaments required for localized outgrowth. Meanwhile, ROP2 inactivates another target RIC1, whose activity promotes well-ordered cortical microtubules. RIC1-dependent microtubule organization not only locally inhibits outgrowth but in turn suppresses ROP2 activation in the indentation zones. Thus, outgrowth-promoting ROP2 and outgrowth-inhibiting RIC1 pathways antagonize each other. We propose that the counteractivity of these two pathways demarcates outgrowing and indenting cortical domains, coordinating a process that gives rise to interdigitations between adjacent pavement cells.
Fu
Ying
Y
Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA 92521, USA.
Gu
Ying
Y
Zheng
Zhiliang
Z
Wasteneys
Geoffrey
G
Yang
Zhenbiao
Z
D008841:Actin Cytoskeleton / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002450:Cell Communication / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D048708:Cell Growth Processes / Q000502:physiology*; D003599:Cytoskeleton / Q000235:genetics / Q000378:metabolism*; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000378:metabolism; D019204:GTP-Binding Proteins; D006131:Growth Inhibitors / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism; D020559:Monomeric GTP-Binding Proteins / Q000378:metabolism; D009024:Morphogenesis / Q000502:physiology; D019441:Plant Epidermis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D018515:Plant Leaves / Q000166:cytology / Q000502:physiology*; D010940:Plant Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D006131:Growth Inhibitors; D020559:Monomeric GTP-Binding Proteins; D010940:Plant Proteins; D020741:rho GTP-Binding Proteins; C499716:RIC4 protein, Arabidopsis; C499714:AT1G20090 protein, Arabidopsis; C083726:ric1 protein, Oryza sativa