Development of genome-driven, lifestyle-informed primers for identification of the cereal-infecting pathogens Xanthomonas translucens pathovars undulosa and translucens

ABSTRACT Bacterial leaf streak, blight and black chaff caused by Xanthomonas translucens pathovars are major diseases affecting small grains. Xanthomonas translucens pv. translucens and X. translucens pv. undulosa are seedborne pathogens that cause similar symptoms on barley, but only X. translucens pv. undulosa causes bacterial leaf streak of wheat. Recent outbreaks of X. translucens have been a concern for wheat and barley growers in the Northern Great Plains and Upper Midwest; however, there are limited diagnostic tools for pathovar differentiation. We developed a multiplex PCR based on whole-genome differences to distinguish X. translucens pv. translucens and X. translucens pv. undulosa . We validated the primers across different Xanthomonas and non- Xanthomonas strains. To our knowledge, these are the first multiplex PCR to distinguish X. translucens pv. translucens and X. translucens pv. undulosa . These molecular tools will support disease management strategies enabling detection and pathovar incidence analysis of X. translucens .