New research groups at MPI-MP aim to unravel how plants defend themselves against viral infections.

The Max Planck Institute of Molecular Plant Physiology welcomes two new independent research group leaders, Dr. Marion Clavel and Dr. Marco Incarbone!

August 03, 2023

With two new research groups "Viral Replication and Plant Tolerance" and "Plant Germline Antiviral Immunity", the institute expands its field of research towards plant interactions with viruses.

Plants also get sick

Like us, plants can also become infected with viruses and fall ill. Since diseased plants produce lower yields, viral diseases cause massive damage to agriculture every year. To breed plants that are better equipped to resist viral infections, it is necessary to understand how viruses infect plants and what mechanisms plants have at their disposal to defend themselves against infection.
Viruses are actually quite simple in structure. They essentially consist of genetic material, i.e. one or more pieces of DNA or RNA, which is packaged in a shell of protein, like a small capsule. When a virus infects a plant cell the genetic material of the virus reprograms its functions. Instead of making proteins for plant growth, the cell becomes a factory for virus capsules and virus genetic material. The newly manufactured viruses then infect other cells and the virus spreads throughout the plant and to new host plants. Viruses have become experts at hijacking cells, rewiring many cellular processes in order to multiply. All this upheaval has profound consequences for the health and longevity of the plant.

Plant cells can detect viruses and fight back 

However, plants are not defenseless. Infected plant cells notice when a virus tampers with them. In some cases, the cells then start a programmed self-destruction mechanism to stop the infection from spreading. After all, without a host cell, viruses cannot replicate. Areas of such dead cells then usually become visible as spots on the plants.
But plants also have ways to limit the damage caused by a virus. One such mechanism is autophagy. The plant cell sets in motion mechanisms that trap and digest unwanted proteins, within the cell. In fact, plants that cannot perform autophagy are sicker than normal plants. How viruses trigger autophagy and how the cell recognizes which proteins need to be digested and which do not is still completely unknown and the research focus of Marion Clavel's group. 

"I would like to decipher the molecular mechanisms that control autophagy in the context of virus infections and possibly unveil previously unknown choke points for the viruses, that could potentially be exploited for growing crops resilient to infection," says Marion Clavel.


The mystery of healthy plant offspring

Plants have developed another barrier to viruses during reproduction and seed development. Viruses very efficiently attack cells of the plant in shoots or leaves. But for reasons that are as yet poorly understood, they seldom infect the vital stem cells from which new tissues are formed at the tip of the shoots. In addition, many viruses cannot infect plant gametes and embryos, which is one of the reasons many infected plants still have healthy offspring. This is quite remarkable, and since stem cells generate the reproductive cells, we are looking at a series of connected and very powerful antiviral mechanisms that remain to be investigated.

"It's amazing how living things have evolved such complex and breathtaking molecular machines that interact in a microscopic dance that to this day is completely beyond our understanding," finds Marco Incarbone.


A shared passion

Their shared fascination for plant viruses already brought the two scientists together at the Institut de Biologie Moléculaire des Plantes of the University of Strasbourg. Both then were lucky to meet again at the Gregor Mendel Institute for Molecular Plant Biology in Vienna, and the MPI-MP is excited to have been able to attract two experts in this field at once.
"You could say the stars really aligned when two positions opened up for independent research group leaders at the MPI-MP, which were just a perfect fit for our careers. But I think it also shows that the MPI-MP is aware of the burden a scientific career places on researchers' social and family relationships. I have previously worked in France and Austria. Germany and especially the Max Planck Society provides excellent access to technical facilities, good opportunities for external funding and networking. I am thrilled to be able to take advantage of all this!" says Marion Clavel.


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