Léa Bogdziewiez has developed new tools that make it possible to study how plant cells attach to each other, a feature that enables trees to grow several meters tall (photo: Roxane Bogdziewiez).
How can a tree grow several meters tall? The answer lies in the ability of plant cells to attach to each other. This process has long been difficult to study, but PhD student Léa Bogdziewiez has developed methods that make it possible to study the process on a whole new level.
- You did your PhD in Stéphane Verger’s research group at UPSC focusing on method development to study plant cell adhesion. What motivated you to work on this topic and start your PhD in Stéphane’s research group?
At first, it was not really the project itself, but mostly the place. I did not want to stay in France where I did my Master’s. When I was searching for a PhD, I looked in Scandinavian countries because I do not like when it is too hot and I wanted to experience something different from France. This was the first position that I was offered and the main reason I applied was the microscopy facility. It is very large, with many different microscopes which were fundamental for the project. I had already done a bit of microscopy already during my master’s and I liked it. So, it was mostly this that got me interested in the project.
- How would you explain cell adhesion and the importance of it for plants?
The aim of my PhD project was to dissect and quantify the forces that are at play between two cells that are attached to each other. Inside plant cells, there is a huge pressure that pushes the plasma membrane against the cell wall but there is also tension caused by growth and external factors such as wind. Plants need to withstand all these types of mechanical stress, but they must also not be too rigid. They need flexibility to grow while keeping their cells attached to each other. Adhesion is therefore a fundamental feature of multicellular organisms and the reason why such large organisms like trees can exist.
- What limits the study of cell adhesion in plants? Why is it necessary to develop new tools?
The problem is that we do not really know which actors are involved, partly because we lack tools to investigate it. Some tools existed to study cell adhesion at the tissue level, such as stretching a tissue to see when it detaches and breaks. The issue is that tissues contain many layers of cells and when looking at this level, it is hard to know where the force is coming from. It is also difficult to identify the molecules involved. That is why we decided to scale down to the cellular level and develop tools to study it. We wanted to look at just two cells to better understand which players are involved and also study how the plasma membrane of a single cell interacts with the surrounding cell wall.
- When summarising your thesis, what do you consider as the major outcome?
I have set up several methods to study cell adhesion in plants which will be especially useful for others working on this topic. It is very challenging to work at the cellular level. Usually, single cells are isolated by removing the cell wall and then force them to regenerate it. The existing methods did not work well for us. So, we optimised them and developed a standardised workflow to extract cells from tissues, keep them alive and increase the regeneration of the cell wall. It is an automatised imaging pipeline based on microscopy images. By using fluorescent markers that label different cell compartments or molecules, we can extract a lot of information. This pipeline can now be used for various purposes such a cell regeneration which might of interest to companies working on regenerating plants from isolated cells. It can also be used to assess how efficiently a gene modification has worked and of course it is very useful to study cell adhesion.
Together with Rubén Casanova Sáez (right) from the C-Trap facility at Umeå University, Léa Bogdziewiez (left) has established a method to measure the forces that hold two plant cells together (photo: Mattias Pettersson, Umeå University).
Then, we used two complementary methods to study adhesion and optimised them for plant cells: a microfluidic shear assay and optical tweezers. In the microfluidics assay, we attached cells to a specific surface and then let a fluid flow over them. This allowed us to measure the force needed to detach them from the surface. Complementary to this, we used optical tweezers which allow us to measure detachment forces on an even smaller scale. With the help of two laser beams cells or molecules can be held in place and by moving them apart, we can measure the force needed to separate them. This was done in collaboration with Rubén Casanova Sáez from the C-Trap Facility at UPSC.
- Were there any results that astonished you or did anything happen along the way that you did not anticipate?
When using the microfluidics approach, I realised that some of the cells form filopodia, small finger-like extensions. This had not been described before. The cells also showed a kind of rolling behaviour somehow staying attached to the surface while moving. It resembled animal cells which use filopodia to move. We use a very artificial set-up, so this might just be an artefact and not biologically relevant, but it was funny to see a “sessile” plant cell moving.
- Are there any challenges you had to overcome during your PhD that you would like to share with us?
The most difficult part was when one of the instruments that we planned to use to monitor the isolated cells broke down. We first tried to fix it but eventually realised it was not possible which was hard to accept at first. We were forced to rethink everything and develop an entire new protocol that did not require this instrument. In the end, it was for the best because that is how we came up with the optimised workflow based on simpler methods which also makes it easier for other scientists to apply.
- What are your next steps now that you have completed your PhD?
First, I will take a break of about two months to spend time with my family and celebrate Christmas together. Then, I would like to continue working with microscopy and image analysis. I also enjoy doing illustrations and creating 3D graphic models and I am considering developing these skills further and offering these services to others.
About the public defence:
Léa Bogdziewiez, Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, defended her PhD thesis on Thursday, 30th of October 2025. Faculty opponent was Jean Christophe Palauqui, INRAE, Institut Jean-Pierre Bourgin (IJPB), Versailles, France. The main supervisor of the thesis was Stéphane Verger.
Title of the thesis: Quantitative imaging and mechanics of single plant cell adhesion
Link to Léa Bogdziewiez’s PhD thesis
For more information, please contact:
Léa Bogdziewiez
Umeå Plant Science Centre
Department of Forest Genetics and Plant Physiology
Swedish University of Agricultural Sciences
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