Genetic diversity and virulence of wheat and barley strains of xanthomonas translucens from the upper midwestern United States

Abstract

Bactcrial leaf streak (BLS) of wheat and barley; caused by Xanihomonas translucens pv. undidosa and X. tmnslucens pv. translucens, has been of growing concern in small grains production in the Upper Midwestern United States. To optimize disease resistance breeding, a greater awareness is needed of the pathovars and genetic diversity within the pathogens causing BLS in the region. Multilocus sequencing typing (MLST) and analyas (MLSA) of four common housekeeping genes (rpoD. dnaK,fyuA, and gyrB) was used to evaluate the genetic diversity of 82 straias of X. translucens isolated between 2006 and 2013 from wheat, barley, rye. And intermediate wheatgrass. In addition, in planta disease assays were conducted on 75 straias to measure relative virulence in wheat and barley. All strains were determined by MLS A to be related to X. translucens pv. undulosa and X. translucens pv. translucens. Clustering of strains based on Bayesian, network, and minimum spanning trees correlated with relative virulence levels in inoculated wheat and barley. Thus, phylogcny based on rpoD. dnaK.fyuA. and gyrB correlated with host of isolation and was an effective means for predicting virulence of strains belonging to X. translucens pv. translucens and X. translucens pv. undulosa.