Theoretical approaches to understanding root vascular patterning: a consensus between recent models.
The root vascular tissues provide an excellent system for studying organ patterning, as the specification of these tissues signals a transition from radial symmetry to bisymmetric patterns. The patterning process is controlled by the combined action of hormonal signaling/transport pathways, transcription factors, and miRNA that operate through a series of non-linear pathways to drive pattern formation collectively. With the discovery of multiple components and feedback loops controlling patterning, it has become increasingly difficult to understand how these interactions act in unison to determine pattern formation in multicellular tissues. Three independent mathematical models of root vascular patterning have been formulated in the last few years, providing an excellent example of how theoretical approaches can complement experimental studies to provide new insights into complex systems. In many aspects these models support each other; however, each study also provides its own novel findings and unique viewpoints. Here we reconcile these models by identifying the commonalities and exploring the differences between them by testing how transferable findings are between models. New simulations herein support the hypothesis that an asymmetry in auxin input can direct the formation of vascular pattern. We show that the xylem axis can act as a sole source of cytokinin and specify the correct pattern, but also that broader patterns of cytokinin production are also able to pattern the root. By comparing the three modeling approaches, we gain further insight into vascular patterning and identify several key areas for experimental investigation.
Centre for Plant Integrative Biology, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK.
Nathan
N
Mellor
Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany.
Milad
M
Adibi
Institute of Biotechnology, University of Helsinki, Helsinki FIN-00014, Finland.|Department of Biosciences, Viikki Plant Science Centre, University of Helsinki, Helsinki FIN-00014, Finland.
Sedeer
S
El-Showk
Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708WE Wageningen, The Netherlands.|Department of Plant Systems Biology, VIB, Technologiepark 927, B-9052, Ghent, Belgium.|Department of Plant Biotechnology and Bioinformatics, VIB, Technologiepark 927, B-9052, Ghent, Belgium.
Bert
B
De Rybel
Centre for Plant Integrative Biology, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK.|School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, UK.|Synthetic Biology Research Centre, The University of Nottingham, University Park, Nottingham NG7 2RD, UK.
John
J
King
Institute of Biotechnology, University of Helsinki, Helsinki FIN-00014, Finland anthony.bishopp@nottingham.ac.uk aripekka.mahonen@helsinki.fi dolf.weijers@wur.nl.|Department of Biosciences, Viikki Plant Science Centre, University of Helsinki, Helsinki FIN-00014, Finland.
Ari Pekka
AP
Mähönen
Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708WE Wageningen, The Netherlands anthony.bishopp@nottingham.ac.uk aripekka.mahonen@helsinki.fi dolf.weijers@wur.nl.
Dolf
D
Weijers
Centre for Plant Integrative Biology, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK anthony.bishopp@nottingham.ac.uk aripekka.mahonen@helsinki.fi dolf.weijers@wur.nl.
Anthony
0000-0003-2962-9542
A
Bishopp
D003583:Cytokinins / Q000378:metabolism / Q000502:physiology; D007210:Indoleacetic Acids / Q000378:metabolism; D008954:Models, Biological; D052585:Phloem / Q000033:anatomy & histology* / Q000502:physiology; D010937:Plant Growth Regulators / Q000502:physiology; D018517:Plant Roots / Q000033:anatomy & histology* / Q000502:physiology; D052584:Xylem / Q000033:anatomy & histology* / Q000502:physiology
D003583:Cytokinins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators
Auxin; cytokinin; mathematical modeling; organ patterning; systems biology; vascular development.