Modelling cell division and endoreduplication in tomato fruit pericarp

Area of Science:

• Plant Biology
• Cell Biology
• Genetics

Background:

• Differentiating plant cells can switch from the classical cell cycle to endoreduplication, a process involving genome duplication without cell division, leading to polyploidy.
• Endoreduplication is crucial for biomass allocation and yield in crops like tomato, influencing fruit size through pericarp cell number and ploidy.
• The karyoplasmic ratio theory suggests a link between nuclear ploidy and cell growth, with polyploidy prevalent in storage tissues.

Purpose of the Study:

• To assess mechanisms initiating endoreduplication in tomato pericarp cells.
• To develop a mathematical model of the cell cycle gene regulatory network for endoreduplication.
• To investigate the role of the phytohormone auxin in regulating the transition to endoreduplication.

Main Methods:

• Development of a mathematical model for the cell cycle gene regulatory network.
• Analysis of regulatory targets for the transition to endoreduplication, focusing on auxin.
• System behavior analysis based on the combined action of multiple regulatory mechanisms.

Main Results:

• Several putative mechanisms can induce endoreduplication in tomato pericarp cells.
• Auxin plays a vital role in regulating the onset of cell expansion, differentiation, and endoreduplication in developing tomato fruit.
• Combined action of multiple regulatory routes enhances the robustness of endoreduplication regulation.

Conclusions:

• The study demonstrates that multiple pathways can trigger endoreduplication in tomato pericarp cells.
• Redundancy in these pathways, particularly influenced by auxin, ensures robust regulation of endoreduplication.
• Understanding these mechanisms can inform strategies for improving crop yield and biomass.