ROLES OF LIPID DROPLETS DURING PLANT VIRUS INFECTION (LIDROVIR) – LiDroVir

Lipid droplets (LDs) are organelles composed of a single phospholipid layer enclosing neutral lipids, involved in energy production, membrane biogenesis and stress signaling. Recently, LDs have also been shown to be required by some animal (+) RNA viruses for their replication. Like animal viruses, plant (+) RNA viruses have to hijack host proteins, intracellular membranes, and lipids to create an optimized lipid/membrane microenvironment for their efficient viral replication compartment (VRC) assembly. Yet the possible involvement of LDs in plant virus infection remains totally unexplored so far. Our recent unpublished results revealed that i) the infection by a plant virus does indeed induce a significant accumulation of neutral lipids and considerable biogenesis of LDs in infected leaf cells ii) these LDs are recruited to the virus-induced VRCs and iii) the plant virus propagation is modified in Arabidopsis mutants of the LD biogenesis machinery. This indicates that at least some plant viruses, similarly to animal ones, may exploit the host LDs for their replication. In the LiDrovir project, we propose, based on a unique consortium with high complementary and transdisciplinary skills in virology, lipid metabolism, imagery and genetics, to decipher the roles of leaf LDs in the plant virus cycle. To this aim, our project is articulated around three main tasks: 1) Exploring the impact of viral infection on the plant LD dynamics; 2) Validating the function of plant LDs in viral infection, and 3) Understanding the molecular mechanisms governing the interactions between LDs and plant viruses. We will focus the project on one viral species and we will aim at expanding our findings on other species of the same viral genus and of agroeconomic importance. Using the major crop Tomato and through genome editing approaches we will assess how this knowledge on the role of LDs can be used to propose genetic resistances to breeders. This project will generate results at the leading front of research about both the mechanisms of the plant virus infection and the still enigmatic functions of LDs in plant leaves.