Host Specificity of Soilborne Pathogens in Hordeum Species and Their Relatives

Soilborne pathogens destabilize the yields of crops, including barley ( L.) and wheat ( L.). Although genetic resistance derived from relatives of these species has been utilized to prevent rust diseases (i.e., in the wheat-rye 1BL-1RS translocation line), research on resistance against soilborne pathogens remains limited. Here, we performed field trials using 76 genotypes representing 28 , six , and two species to examine resistance against three soilborne bymoviruses: barley yellow mosaic virus (BaYMV), barley mild mosaic virus (BaMMV), and wheat yellow mosaic virus (WYMV). We also performed greenhouse tests using the soilborne fungal pathogen , which causes Fusarium crown rot (FCR). Using RT-PCR, we detected BaMMV and BaYMV in several species, whereas WYMV induced systemic infection in the and species. The identification of FCR susceptibility in all species examined suggests that is a facultative fungal pathogen in . Intraspecies variation in FCR disease severity was observed for several species, pointing to the possibility of exploring host resistance mechanisms. Therefore, by unlocking the host specificity of four soilborne pathogens in species and their relatives, we obtained insights for the further exploration of wild sources of soilborne pathogen resistance for future wheat and barley improvement programs.