Biology and biotechnology of grapevine viruses

Group leader : Christophe RITZENTHALER

Research area

Many viruses are among the most damaging and widespread pathogens of grapevine worldwide (fanleaf, leafroll, etc…). At the interface between basic and applied research, the overall objective of the group ” Biology and biotechnology of grapevine viruses” is to better understand the biology of these viruses. In particular, our aim is to decipher their interactions with host plants, how they move from cell to cell via plasmodesmata and how they are transmitted by nematode vectors. This allows us to develop new tools or strategies to fight against these pathogens: detection and agrodiagnostic tools using Nanobodies, virus-resistant plants, biotechnology applications derived from Virus Like Particles (VLPs), etc… Our aim is also to strengthen our position among the international leaders in plant virology and biotechnology.


Production of Nanobodies against major grapevine viruses

Nanobodies (Nbs) are small peptides derived from single-chain only antibody found in camelids. Discovered in the 90s, Nbs are the smallest known antibody-like molecules and are of great interest in biotechnology. We showed that Nbs directed against Grapevine fanleaf virus (GFLV) possess antiviral activity and confer resistance to the virus. They can also be used for the immunodetection of the virus and are excellent GFLV biosensors in planta. Based on these proof of concepts, we aim at developing Nbs against other major grapevine viruses responsible of fanleaf- (nepoviruses), leafroll- (ampelovirus) and rugose wood complex-(vitiviruses) diseases.

Nanotechnology of nepoviruses

Viruses of the genus nepovirus are formed by the self-assembly of 60 identical capsid protein (CP) subunits. We have shown that this highly ordered protein backbone complex of about 30 nm in diameter can serve as a versatile platform for the display and encaging of macromolecules. Our goal is to optimize this platform for various nanotechnology uses such as vaccinology, molecular therapy or imaging.

Mechanisms of replication, movement and transmission of Grapevine fanleaf virus

The historical interest of the group is focused on the biology of Grapevine fanleaf virus (GFLV), a severe pathogen of grapevine worldwide. Genetic approaches combined to biochemistry, imaging and structural biology have enabled us to elucidate certain key molecular elements of the cell-to-cell movement mechanism via plasmodesmata and the plant-to-plant transmission mode by its nematode vector. Our goal now is to vizualize these key viral multiplication stages in real time by in vivo non-invasive approaches using fluorescent probes in order to better understand the molecular mechanisms.