Things to do before you die: The bucket list of a plant cell
Wang, Bollier, Buono, et al. catalog the cellular processes that occur during programmed cell death in plants.
https://doi.org/10.1093/plcell/koad308
Jie Wang, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
Moritz K. Nowack, VIB-UGent Center for Plant Systems Biology, Gent, Belgium
Background: Programmed cell death (PCD) is a genetically controlled process causing the targeted death of specific cells. Plants use PCD to fight pathogens, but also during development, growth and reproduction. Efficient water transport from the roots to the leaves for instance relies on PCD to produce a network of dead hollow xylem cells that function as water conduits. However, despite the importance of PCD for plant development, information on the cellular mechanisms that execute PCD in plants remains fragmentary.
Question: We set out to generate a detailed inventory of the cellular processes that occur during PCD execution in plants. We wanted to know which processes occur, and in which order they facilitate a controlled cessation of vital cellular functions.
Findings: Making use of the accessibility of the Arabidopsis thaliana root cap for live-cell confocal microscopy imaging, we followed the fate of different cellular compartments in a high spatial and temporal resolution. We identified a succession of ordered and stepwise events causing the breakdown of cellular compartmentalization that is necessary to keep cells alive. We found that an increase of intracellular calcium and proton levels, accompanied by mitochondrial breakup, are the earliest events in PCD execution. Only minutes later, the nucleus and the endoplasmic reticulum collapse, releasing their contents into the cytosol. Finally, the large central vacuole breaks up, and the plasma membrane becomes permeable to dyes that cannot normally enter the cell. Intriguingly however, the plasma membrane remains largely intact after cell death execution, effectively restricting the release of proteins from dead cells.
Next steps: We found that the order of cellular de-compartmentalization events is under genetic control. Hence we are now entering an exciting phase of research in which we will attempt to find molecular regulators for the individual PCD execution steps that jointly cause cellular death and breakdown.
Reference:
Jie Wang, Norbert Bollier, Rafael Andrade Buono, Hannah Vahldick, Zongcheng Lin, Qiangnan Feng, Roman Hudecek, Qihang Jiang, Evelien Mylle, Daniel Van Damme, and Moritz K. Nowack. (2024). A developmentally controlled cellular decompartmentalization process executes programmed cell death in the Arabidopsis root cap. https://doi.org/10.1093/plcell/koad308
