Plant resistance to viruses induced by CytoRP, an RNase P-derived protein – CytoRP

Because PRORP is not expressed in the same subcellular compartments where viral multiplication takes place, such a process is very unlikely to occur spontaneously. To promote the colocalization of PRORP and their viral RNA targets, a cytosolic version of PRORP, referred to as CytoRP has been obtained. This invention was recently protected by a European patent and the aim of this project is now to validate its use as an antiviral strategy in plants. Preliminary results show that cleavage of virus TLS can be achieved by CytoRP in vitro and also suggest that transgenic lines expressing Cyto RP can display resistance to viral infection in vivo.

-Detailed characterization of the RNase P activity (TYMV TLS cleavage) of CytoRP.
-Obtention of a range of plants expressing CytoRP under the control of different promoters (native and 35S) and possessing different levels of CytoRP expression.
-Construction of CytoRP plants by genome editing using CRISPR-Cas9 technology.
Preliminary results concerning the in vivo resistance of CytoRP plants to viral infections.

The CytoRP research project and valorisation strategy are as follows: first, the use of CytoRP as an antiviral strategy will be validated using Arabidopsis thaliana and Turnip yellow mosaic virus (TYMV) as a model pathosystem. Then, CytoRP technology will be applied to a pathosystem of economical relevance such as tomato and Cucumber mosaic virus (CMV). Finally, CytoRP lines will be generated by genome editing strategies (such as the CRISPR-Cas9 technology), in order to determine whether the antiviral resistance can be obtained using point mutations or short genomic deletions.

Gobert, A., Giegé, P. « Methods for increasing the resistance of a plant to a plant RNA virus » European patent office, N°EP14305771.9.
Extension international en cours d’évaluation.

Moriceau L, Jomat L, Bressanelli S, Alcaide-Loridan C, Jupin I. (2017) Identification and Molecular Characterization of the Chloroplast Targeting Domain of Turnip yellow mosaic virus Replication Proteins. Front Plant Sci. 8:2138.

The project CytoRP aims at developing plants that are resistant to viral infections thanks to the use of a novel technology designated CytoRP.

It is based on the use of PRORP proteins, a novel family of plant RNase P enzymes involved in the maturation of tRNA precursors. These enzymes can, not only recognize and cut tRNAs, but also tRNA-like structures (TLS), such as the ones harboured at the 3’ end of the viral genome of many plant viruses. As such structures are essential for viral infectivity, their cleavage by PRORP is expected to prevent viruses from replicating and therefore would protect plants from infection.

However because PRORP is not expressed in the same subcellular compartments where viral multiplication takes place, such a process is very unlikely to occur spontaneously. To promote the colocalization of PRORP and their viral RNA targets, a cytosolic version of PRORP, referred to as CytoRP has been obtained. This invention was recently protected by a European patent and the aim of this project is now to validate its use as an antiviral strategy in plants. Preliminary results show that cleavage of virus TLS can be achieved by CytoRP in vitro and also suggest that transgenic lines expressing Cyto RP can display resistance to viral infection in vivo.

This project will be achieved by a collaborative effort between two academic laboratories with complementary expertise: Partner 1 (Team “Function of PPR proteins”, Institut de Biologie Moléculaire des Plantes, Strasbourg, PI : Philippe Giegé) who discovered PRORP proteins in plants and developed the CytoRP technology, and Partner 2 (Team “Molecular Virology”, Institut Jacques Monod, Paris, PI: Isabelle Jupin), specialized in molecular and cellular plant virology.

The aim of this project is to provide an essential proof of concept for the CytoRP technology, which constitutes a prerequisite step for its future commercial applications, as defined in conjunction with industrial partners.

The CytoRP research project and valorisation strategy are as follows: first, the use of CytoRP as an antiviral strategy will be validated using Arabidopsis thaliana and Turnip yellow mosaic virus (TYMV) as a model pathosystem. Then, CytoRP technology will be applied to a pathosystem of economical relevance such as tomato and Cucumber mosaic virus (CMV). Finally, CytoRP lines will be generated by genome editing strategies (such as the CRISPR-Cas9 technology), in order to determine whether the antiviral resistance can be obtained using point mutations or short genomic deletions.

We expect this project to generate plants with a broad spectrum of viral resistance and thus to serve as a proof of concept for industrial partners, with the goal of increasing crop yields with a limited use of pesticides.