Modelling cell division and endoreduplication in tomato fruit pericarp.
In many developing plant tissues and organs, differentiating cells switch from the classical cell cycle to an alternative partial cycle. This partial cycle bypasses mitosis and allows for multiple rounds of genome duplication without cell division, giving rise to cells with high ploidy numbers. This partial cycle is referred to as endoreduplication. Cell division and endoreduplication are important processes for biomass allocation and yield in tomato. Quantitative trait loci for tomato fruit size or weight are frequently associated with variations in the pericarp cell number, and due to the tight connection between endoreduplication and cell expansion and the prevalence of polyploidy in storage tissues, a functional correlation between nuclear ploidy number and cell growth has also been implicated (karyoplasmic ratio theory). In this paper, we assess the applicability of putative mechanisms for the onset of endoreduplication in tomato pericarp cells via development of a mathematical model for the cell cycle gene regulatory network. We focus on targets for regulation of the transition to endoreduplication by the phytohormone auxin, which is known to play a vital role in the onset of cell expansion and differentiation in developing tomato fruit. We show that several putative mechanisms are capable of inducing the onset of endoreduplication. This redundancy in explanatory mechanisms is explained by analysing system behaviour as a function of their combined action. Namely, when all these routes to endoreduplication are used in a combined fashion, robustness of the regulation of the transition to endoreduplication is greatly improved.
Biometris, Wageningen University and Research Center, 6708 PB Wageningen, The Netherlands; Netherlands Consortium for Systems Biology, 1090 GE, Amsterdam, The Netherlands; Industrial and Financial Mathematics Group, Bandung Institute of Technology, Bandung 40132, Indonesia. Electronic address: m.apri@math.itb.ac.id.
Mochamad
M
Apri
Greenhouse Horticulture, Wageningen University and Research Center, The Netherlands.
Johannes
J
Kromdijk
Greenhouse Horticulture, Wageningen University and Research Center, The Netherlands.
Pieter H B
PH
de Visser
Biometris, Wageningen University and Research Center, 6708 PB Wageningen, The Netherlands; Netherlands Consortium for Systems Biology, 1090 GE, Amsterdam, The Netherlands.
Maarten
M
de Gee
Biometris, Wageningen University and Research Center, 6708 PB Wageningen, The Netherlands; Netherlands Consortium for Systems Biology, 1090 GE, Amsterdam, The Netherlands.
Jaap
J
Molenaar
D002455:Cell Division; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D016213:Cyclins / Q000378:metabolism; D050684:E2F Transcription Factors / Q000378:metabolism; D062951:Endoreduplication; D005638:Fruit / Q000166:cytology* / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism; D018551:Solanum lycopersicum / Q000166:cytology* / Q000235:genetics; D008954:Models, Biological
D016213:Cyclins; D050684:E2F Transcription Factors; D007210:Indoleacetic Acids; D018844:Cyclin-Dependent Kinases
Cell cycle; Endoreduplication; Mathematical model; Phytohormone auxin; Tomato fruit pericarp