This study investigated the impact of brassinosteroid (BR)-insensitive 1 (BRI1) mutation, the main receptor of BR inboth Brachypodium distachyon and barley, on diseaseresistance against a range of fungal pathogens of cerealsexhibiting different trophic lifestyles. Results presentedhere show that (i) disruption of BRI1 has pleiotropic effectson disease resistance in addition to affecting plantdevelopment. BR signaling functions antagonistically withmechanisms of disease resistance that are effective againsta broad range of cereal pathogens. (ii) Disruption of BRI1results in increased disease resistance against necrotrophicand hemibiotrophic pathogens that exhibit only a marginalasymptomatic phase but has no effect on biotrophicpathogens or those with a prolonged asymptomatic phase,and (iii) disruption of BRI1 has a similar effect on diseaseresistance in B. distachyon and barley, indicating thatdefense mechanisms are conserved between these species.This work presents the first evidence for conservation ofdisease resistance mechanisms between the model speciesB. distachyon and the cereal crop barley and validates B.distachyon for undertaking model-to-crop translationstudies of disease resistance.