Abstract EN:

Beet necrotic yellow vein virus is the causal agent of the sugar beet rhizomania, an economically important disease whose molecular basis remains poorly understood. In an attempt to address this issue, an RFDD-PCR approach was used to compare the global gene expression profiles of healthy and infected root systems. This analysis indeed revealed differentially regulated genes, however, confirmation of the observed changes by nucleic acid hybridization methods was difficult, presumably because of the intrinsic complexity of the pathosystem investigated. A more amenable transgenic approach was therefore developed in parallel, in which the RNA-3-encoded p25 protein -the presumed major symptom determinant in rhizomania- was constitutively expressed in Arabidopsis thaliana. Detailed phenotypic characterization of established transgenic lines together with hormonal and viral sensitivity assays have provided valuable clues as to how P25 might promote disease development and symptom expression in authentic infection contexts. Furthermore, preliminary interpretation of comparative micro-array analyses carried out with RNAs from roots of wild-type and transgenic plants support our phenotypic observations.