Clubroot, caused by the obligate biotroph Plasmodiophora brassicae, is one of the economically most important diseases of Brassica crops in the world including B. oleracea (coles), B. napus (oilseed rape) and B. rapa (turnip). The breeding of resistant cultivars is currently a main goal to control this disease in all Brassica crops. Very few resistant varieties are currently available especially for coles and oilseed rape. The model plant Arabidopsis thaliana is also a host for clubroot and shows natural variation in the responses to clubroot infection. Genetical genomics analyses of the plant response to clubroot infection are in progress in our team in order to determine which structural and functional characteristics of the resistance factors have to be taken into account to build resistant varieties in a complex environment. The aim of the present work was to investigate synteny of the regions carrying resistance factors to clubroot through a comparative structural study in the three Brassica crops (B. napus, B. oleracea and B. rapa) and in the model species A. thaliana and to identify underlying candidate genes. In the past, genetic analyses for resistance to various P. brassicae isolates have been performed in these four species and major genes and quantitative trait loci (QTL) with high or moderate effect have been identified. Thanks to the recent availability of the genome sequence for these species, the genes underneath the detected regions and their orthologs were determined for each species and compared. Results showed that some QTL genomic regions were syntenic between these species and common underlying genes were identified. Several other regions/genes were specific to one plant species. The existence of common and specific regions in these Brassicaeae species is discussed in the light of both evolutionary aspects and implications for the construction of durable resistant varieties.