Soil-borne cereal mosaic virus (SBCMV) is the viral agent causing wheat mosaic virus, a widely diffused wheat disease. SBCMV belongs to the genus Furovirus and is transmitted by the plasmodiophorid Polymyxa graminis. Following root infection, SBCMV is translocated to the shoots causing stunting and mosaic symptoms on leaves. Two major SBCMV resistance genes are known: Sbm1 in hexaploid wheat (chromosome 5D) and Sbm2 in both hexaploid and tetraploid wheat (chromosome 2B). QSbm.ubo-2BS = Sbm2 has been characterized in Meridiano (Resistant) X Claudio (Susceptible) durum population as a unique major QTL (R2 = 88.5%) within a 2 cM-wide interval in the distal region of chromosome arm 2BS, with wPt-2106 (DarT®) as the closest marker (Maccaferri et al., 2011). Our objective was to molecularly characterize Sbm2 and to develop novel breeder-friendly diagnostic assays. Based on a cultivated durum wheat panel, iSelect 90K and Affymetrix 420K SNP arrays were used to define resistant-and susceptible-SNP haplotypes in the Sbm2 confidence interval. Five iSelect and 11 Affymetrix SNPs were converted to KASP® and used to fine-map the QTL interval using three novel segregating populations (Svevo x Ciccio, Meridiano x MC110 line). Eventually, 20 recombinant lines were detected and the QTL interval was narrowed down to 1.5 Mb. The comparison of the gene content in three wheat reference genomes (Zavitan, Svevo and Chinese Spring) pointed out that some 20 genes in the region were involved in disease resistance response (NBS-LRR), kinase signaling (MAPK) and membrane receptor kinases. Furthermore, RNAseq data from noninfected root seedling tissues of 13 resistant and susceptible varieties were analyzed (Ormanbekova et al., unpublished) and nine genes within the interval were upregulated (NBS-LRR and kinase receptors) and 4 genes were downregulated (membrane receptors) in roots of resistant varieties as compared to susceptible ones. All these genes can be considered candidates for Sbm2 and further functional characterization is required. Flanking markers were also useful to analyze two new large populations obtained by crossing resistant and susceptible parents (Monastir x Odisseo and Relief x Iride) and informative recombinants are being increased for SBCMV characterization. Additional approaches being considered for sbm2 characterization are: 1) two emmer panels (T. dicoccum and T. dicoccoides panel lines) that showed a locally faster LD decay rate as compared to durum, 2) a panel of Svevo Tilling mutants (ca. 2,000 lines) is also being screened directly in the field (forward genetics) and will also be considered for validation of candidate genes.