Résumé : Plant root-knot nematode interaction studies are performed on several host plant models. Though root-knot nematodes interact with trees, no perennial woody model has been explored so far. Here we show that poplar (Populus tremula x P. alba) grown in vitro is susceptible to Meloidogyne incognita allowing this nematode to penetrate, to induce feeding sites and to successfully complete its life cycle. Quantitative RT-PCR analysis was performed to study changes in poplar gene expression in galls compared to non-infected roots. Three genes (expansin A, histone 3.1 and asparagine synthase), selected as gall development marker genes, followed during poplar-nematode interaction a similar expression pattern to what was described for other plant hosts. Down-regulation of four genes implicated in the monolignol biosynthesis pathway was evidenced in galls, suggesting a shift in the phenolic profile within galls developed on poplar roots. Raman microspectroscopy demonstrated that cell walls of giant cells were not lignified but mainly composed of pectin and cellulose. The data presented here suggest that RKN exercise conserved strategies to reproduce and to invade perennial plant species and that poplar is a suitable model host to study specific traits of tree-nematode interactions.