A NEW DISEASE OF MAIZE AND WHEAT IN THE HIGH-PLAINS

Dent corn, sweet corn, and blue corn showing severe viruslike symptoms were found in Texas, Kansas, Colorado, Idaho, Nebraska, and Utah in 1 993 and 1994. The disease can be devastating to susceptible genotypes, and was also found in wheat. Pathogen nucleoproteins from the infecte d tissue were concentrated by ultracentrifugation and analyzed by sodi um dodecyl sulfate-polyacrylamide gel electrophoresis revealing the co at protein of wheat streak mosaic virus (WSMV) and a unique, approxima tely 32-kDa protein. Extraction of symptomatic tissue and purification by density gradient centrifugation yielded a product with a nearly pu re 32-kDa protein but no defined viruslike structure. Neither electron microscopy of leaf dip preparations nor density gradient purification trials consistently revealed particles other than WSMV. An antiserum has been prepared to the 32-kDa antigen. The pathogen, which we have t ermed the high plains virus, is transmitted by eriophyid mites.