EU funds groundbreaking research on mitochondria in Potsdam

Max Planck Institute in Potsdam receives EU funding of 2.5 million euros for groundbreaking research on plant mitochondria.

April 12, 2024

Prof. Dr. Ralph Bock at the Max Planck Institute of Molecular Plant Physiology in Potsdam (Germany) receives an Advanced Grant from the European Research Council (ERC) worth € 2.5 million to develop groundbreaking molecular genetic research methods. The "PlaMitEng" research project will for the first time allow targeted genetic modifications to be made in the genome of mitochondria.

Plants have three genomes

The development of modern genetic engineering revolutionized biological research and opened up previously unimagined possibilities, particularly in plant research and plant breeding. The basic techniques of molecular biology are so fundamental that they have long since found their way into school textbooks. But unsolved challenges in molecular biology still remain.  Ralph Bock's research group at the Max Planck Institute of Molecular Plant Physiology in Potsdam is now addressing one of these challenges in its PlaMitEng (Plant Mitochondrial Engineering) project, which is being funded by the European Union with an ERC Advanced Grant worth €2.5 million.

Genetic engineering work on plants is complicated. If you look closely, plants have not just one genome, but three! The majority of plant genes are located in the cell nucleus. However, plant cells also have other components (organelles) with their own genome, including chloroplasts and mitochondria. Chloroplasts and mitochondria are descended from bacteria that were captured more than a billion years ago by precursors of modern plant cells. Since then, they function as a community, but both organelles still carry their own genetic information and reproduce within the plant cells by division. Chloroplasts capture energy from sunlight and store it as sugar through photosynthesis. In the mitochondria, the plant cells metabolize this sugar and use the energy for growth and reproduction. As major sites of energy conversion, chloroplasts and mitochondria are therefore essential for the metabolism and growth of plants.

Targeted genetic modification of mitochondria is not yet possible

However, it is precisely these organelles that are particularly difficult to access for molecular biologists. Targeted modifications using the CRISPR gene scissors are not possible in organelles, as the scissors have to be produced in the cell nucleus and not all of their parts find their way into the organelles.

To make matters worse, so-called selection markers for organelles are very difficult to develop. Experiments in molecular biology involve hundreds of thousands or millions of cells. Selection markers make it possible to distinguish the few successfully genetically modified cells from the majority of cells that have not been successfully modified. These markers are usually genes that confer resistance to an antibiotic. If the plant cells are exposed to this antibiotic in the experiment, only the successfully modified cells that carry the selection marker survive. The rest are "selected out". Almost all molecular genetic research on chloroplasts was made possible by the discovery of a single selection marker in the 1990s, which gives the modified chloroplasts resistance to the antibiotic spectinomycin. This gene made it possible to specifically isolate cells that carry genetic changes in their chloroplast genome. The discovery of this marker was instrumental in enhancing our current understanding of how photosynthesis, the important plant metabolic process that ensures our survival on this planet, works.

New method will open up new areas of research

Despite more than 30 years of intensive research, no such selection marker has yet been found for mitochondria. Consequently, the functionality of the mitochondrial genome is still to be revealed. Ralph Bock's research group has now set out to unravel this mystery. The ERC project PlaMitEng will develop new methods to introduce targeted changes to genes in the mitochondria, similar to the way the CRISPR gene scissors allow this to be done in the cell nucleus. The aim is to develop selection systems that allow plant cells with altered mitochondria to be distinguished from those with altered chloroplasts or cell nuclei. "The ability to modify plant mitochondrial genomes will open up completely new possibilities in both basic and applied research. Mitochondria and their genomes also offer unique potential for biotechnology and synthetic biology, and this potential could then finally be fully exploited," says Ralph Bock, head of the research project.

Advanced Grants from the European Research Council (ERC) are among the most prestigious and competitive funding programs in the EU. Funding is provided to leading researchers with ambitious projects that could lead to major scientific breakthroughs. In this funding period, a total of €652 million in ERC Advanced Grants were awarded to researchers. The success rate for applications was 13.9%.

Ralph Bock is Director at the Max Planck Institute of Molecular Plant Physiology in Potsdam Golm. He heads the "Organelle Biology, Biotechnology and Molecular Ecophysiology" department, which deals in particular with metabolic processes in mitochondria and chloroplasts and with the interaction of the genetic material in the organelles with the cell nucleus. He is one of the world's leading scientists in the field of organelle research and is a member of the National Academy of Sciences (Leopoldina) in Germany and the National Academy of Sciences of the United States of America.

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