DUSSUTOUR Ange

Inter-organism silencing is a new pathway of molecular dialogue in parasitic interactions. This process is based on the exchange of small non-coding RNAs (ncRNAs) between a parasitic or pathogenic organism and its host. Identified in the interaction between the vertebrate parasitic nematode Heligmosomoides polygyrus and the mouse (Buck et al. 2014), it has recently been demonstrated in a fungus and a plant pathogenic oomycete interacting with the model plant Arabidopsis thaliana (Cai et al. 2018; Dunker et al., 2020). Nematodes of the genus Meloidogyne are pests of major agronomic importance. To date, no studies have been conducted to characterise the exchange of small ncRNAs during plant-nematode interactions. The aim of this thesis project is to characterise the role of plant and nematode small RNAs in the inter-organism silencing process during the interaction between a plant of agronomic interest, the tomato Solanum lycopersicum, and the model root-knot nematode Meloidogyne incognita. Initial work based on sequencing techniques has identified several candidates: small RNAs from the nematode and their target transcript in the plant and small RNAs from the plant and their target transcript in the nematode. Direct identification and functional analysis approaches will be used to validate and determine the role of the identified small RNAs in the plant-root nematode interaction. This project will open new perspectives in the study of host-parasite dialogue and the development of new pest management strategies.