Our study aimed to investigate the relationship between endoreduplication and cell size regulation through genetic, cell biological, and physiological experiments. Using a simple system of hypocotyl bending, we identified an integrative signaling pathway that explains how endoreduplication regulates cell size. Our key findings include: (i) Establishing a connection between nuclear DNA content control via endoreduplication and cell size regulation through the mechano-chemical properties of the extracellular matrix, specifically the cell wall in plants. (ii) Demonstrating that disrupting the endoreduplication machinery leads to the stiffening of the cell wall by increasing pectin methylesterification through the upregulation of the ERF115 family of AP2 transcription factors' expression. (iii) Showing that mechano-chemical changes due to the reduction of endoreduplication are transmitted by cell wall integrity kinase THESEUS1, ultimately leading to growth repression. (iv) Using the Arabidopsis hypocotyl bending system, we illustrate how asymmetric hormonal responses spatially pattern endoreduplication, resulting in differential growth regulation.
Despite the century-old recognition of the correlation between cell size and ploidy, Theodor Boveri's sea urchin experiments did not reveal the underlying mechanism. Our study presents a previously unknown mechanism that links ploidy with the control of cell size, offering an explanation for the enigmatic role of endoreduplication in morphogenesis. Our results have far-reaching implications for the robustness of development, the integration of growth regulators and mechanics in cell size control, and compensatory mechanisms that explain how organs robustly change and acquire their shapes.
The research project has resulted in a paper published in the prestigious Science family journal, Science Advances. The findings have been disseminated through various platforms, including the hosting website, ResearchGate, and Twitter. Furthermore, our results have inspired related research on other species, such as aspen, to explore their breeding potential. We anticipate further collaboration with biotechnology companies to promote the translation of our research.
