Bacterial leaf streak (BLS) is an increasingly important disease of cereals caused by the bacterial pathogen Xanthomonas translucens. The disease is characterized by an initial water-soaked streaks that turn to chlorotic/necrotic lesions reducing photosynthetic capacity and potentially impacting yield and grain quality.

BLS is difficult to manage due to limited sources of resistance in cultivated barley, variation among pathogen populations, and strong environmental influences on disease development. Addressing these challenges requires a deeper understanding of both the pathogen and the barley host across diverse growing conditions.