pv. Identified on Common Weedy Grasses in Naturally Infected Wheat Fields in Minnesota.

Bacterial leaf streak (BLS) of wheat, caused by pv. , has been a notable disease in Minnesota wheat fields over the past decade. Potential sources of the pathogen include infested seed and crop debris. Perennial weeds are also considered a possible inoculum source, but no surveys have been conducted to evaluate which pathovars are present on weedy grasses that are common in Minnesota wheat fields. Multilocus sequence analysis (MLSA) of four housekeeping genes (, , , and ) was used to identify 77 strains isolated from six weedy grass species, wheat, and barley in and around naturally infected wheat fields in Minnesota. The MLSA phylogeny identified all strains originating from weedy grass species, except smooth brome, as pv. , whereas strains isolated from smooth brome were determined to be pv. . In planta character states corroborated these identifications on a subset of 41 strains, as all strains from weedy grasses caused water-soaking on wheat and barley in greenhouse assays. Multilocus sequence typing was used to evaluate genetic diversity and revealed that sequence types of pv. originating from weedy grass hosts are similar to those found on wheat. This study identifies both annual and perennial poaceous weeds common in Minnesota that harbor pv. and expands our understanding of the diversity of the pathogen population.