Aggressiveness of Xanthomonas translucens pv. undulosa Isolates and Differential Reaction Among Spring Wheat Varieties Under Controlled Environment

Xanthomonas translucens pv. undulosa (Xtu) causes bacterial leaf streak (BLS) in wheat that can lead up to 40% losses globally. Understanding the aggressiveness of isolates from different locations in a state may help in screening for BLS resistance in wheat breeding programs for that area. A greenhouse study to determine the aggressiveness of 17 isolates collected from South Dakota on spring wheat cv. ‘SY-Rockford’; and differential reaction of 21 spring wheat varieties grown in South Dakota to BLS under greenhouse conditions was conducted in 2021 and 2022. To assess BLS severity, one randomly selected plant per pot was rated based on the percentage of leaf area with BLS symptoms. Significant differences among the bacterial isolates were observed, with Xtpvu21OC (23.33%) as the most aggressive in causing BLS in SY-Rockford. Spring wheat varieties ‘MN Washburn’ (25.0%) and ‘ND Frohberg’ (22.5%) were found to be the most susceptible to BLS. It is suggested that the most aggressive Xanthomonas translucens pv. undulosa isolate available to researchers in their region be used in screening varieties and lines for BLS resistance.