Abstract :

Root knot nematodes (RKNs) are endoparasitic worms that invade plant roots causing economically important damages worldwide as they have a wide host range. Furthermore, RKN populations are predicted to geographically spread and to increase with climate warming. Through their stylet (a syringe-like organ), these pests inject proteins, known as effector, into plant cells to manipulate diverse functions to their advantage and to escape plant defenses. Indeed, RKNs induce in the root the formation of giant polynucleate cells, which constitute their feeding sites to drain plant nutrients, thus affecting plant yield. Understanding the molecular dialog between the plant and root knot nematodes is therefore of high interest to build new strategies of plant protection against these parasites.

A combination of comparative genomics and transcriptomics allowed the prediction of RKN secreted effectors. In situ hybridization confirmed effector expression in RKN salivary glands, indicating they could be injected in planta. Agro-infiltration of GFP-tagged effectors in tobacco helped select RKN effectors targeting the plant cell nucleus. Yeast two-hybrid screening identified potential targets of the effector MiEFF186 involved in ribosome biogenesis in the tomato plant. Co-localization of MiEFF186 and its target revealed the interaction in plant nucleolus. This suggests RKNs manipulate plant nucleolar functions to establish feeding sites in planta. Functional analysis of these targets will be presented.

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https://inrae-fr.zoom.us/j/5785660130?omn=91335542037