POSTERS: Population biology and genetics
Characterization of bacterial leaf streak of corn in Minnesota
Dean Malvick - University of Minnesota, Department of Plant Pathology. Crystal Floyd- University of Minnesota
Bacterial leaf streak (BLS) is an invasive disease of corn caused by Xanthomonas vasicola (XV). This disease was first confirmed in the USA, including two counties in Minnesota, in 2016. The goal of this project is to understand the distribution and characteristics of this pathogen in Minnesota field corn and sweet corn production fields. Corn leaves with typical symptoms of BLS, i.e., brown to yellow narrow leaf lesions, were collected from multiple fields and counties across southern Minnesota in 2017 and 2018. Leaf samples were tested for bacterial streaming and for the presence of XV directly with a specific PCR assay and via isolations on media. BLS and XV have been confirmed in eight counties, and BLS has been reported based on symptoms in at least 10 additional counties in southern and central Minnesota. Three isolates of XV obtained from symptomatic leaves were confirmed via sequencing of the 16S rRNA gene, and virulence was tested on field corn and sweet corn in greenhouse experiments with four inoculation methods. Disease severity was assessed weekly for 3 weeks after inoculation. Isolates of XV differed significantly in virulence on field and sweet corn and the method of inoculation significantly influenced development of BLS.