Soil tripartite interactions between host plants, viruses and the protist vectors Polymyxa

Genard, Margaux [UCL] Decroës, Alain Bragard, Claude [UCL] Legrève, Anne [UCL]

Viral diseases transmitted by Polymyxa involve complex soil-borne pathosystems involving three actors: a plant host, a root obligate endoparasitic protist vector (Polymyxa spp.) and viruses. These pathosystems are spread worldwide, in both temperate and tropical areas. They affect numerous host plants (both monocotyledons and dicotyledons) due to the large diversity of the Polymyxa-virus pathosystems. Our research aims to assess how the host plant,Polymyxa and the viruses they vector interact, mainly focusing on two Polymyxa-virus models for which genomic data are available : (1) the Polymyxa betae – Beet necrotic yellow vein virus (BNYVV) pathosystem on sugar beets and (2) the Polymyxa graminis – Rice stripe necrosis virus (RSNV) pathosystem on rice. Recent genomic and transcriptomic data regarding the vector Polymyxa open new pportunities to understand the nature and specialization of the Polymyxa-host interactions. It allows a better understanding of how Polymyxa manage to bypass host defenses and paves the way for identifying effectors involved in host defenses manipulation. Additionally, the first transcriptomic data of in vivo transmission of virus by Polymyxa clarify how the virus impacts plant defenses and therefore Polymyxa-host interactions. These transcriptomic results also give insight on the specificity Polymyxa-virus interactions