B.THE HIGH PLAINS VIRUS, REPRESENTATIVE OF A NEW VIRAL GROUP WITH POSSIBLE WORLD WIDE DISTRIBUTION.
B.THE HIGH PLAINS VIRUS, REPRESENTATIVE OF A NEW VIRAL GROUP WITH POSSIBLE WORLD WIDE DISTRIBUTION. SG JENSEN1, WA FITHIAN2, JA BERRY3, EM BALL4 and JS HALL11 1USDA-ARS, Lincoln, NE; 2Golden Harvest Seeds, Waterloo, NE; 3Pioneer Hi-Bred International Inc., Johnston, IA; 4University of Nebraska, Lincoln, NE Background and objectives The high plains virus (HPV) was first identified during an epidemic in maize in the western plains of the USA in 1993. It is a member of a possible new group of plant pathogens that are transmitted only by eriophyid mites and that produce large double membrane bound bodies in infected cells. Other members of this group of pathogens include fig mosaic, rose rosette, thistle mosaic, redbud yellow ringspot and wheat spot mosaic virus. HPV is transmitted by the eriophyid mite, Aceria tosichella, and may be similar to wheat spot mosaic virus however, an authentic culture of that virus is not available for comparison. HPV can be lethal to susceptible maize, Zea mays, wheat, Triticum aestivum, barley, Hordium vulgare, and other grasses. In all hosts there is a characteristic 32 kDa N-protein specific to HPV infection and an antiserum to that protein has been prepared for diagnostic and research studies. The HPV genome, which has been largely sequenced, consists of at least four dsRNA species of approximately 900 to 2400 base pairs in size. RNA #3 directs for the formation of the 32 kDa protein. There is no sequence similarity with other known sequences nor are the other properties of HPV characteristic of any other plant or animal virus group. Because the virus can be devastating to our most important cereal crops we undertook to determine the distribution of HPV in the USA and other countries around the world. Methods and materials Samples of HPV infected tissue were obtained in two ways. Contributors who suspected HPV infection, submitted samples of maize, wheat and other grasses to our laboratories for diagnostic analysis. Many corn samples came from a survey that we conducted in 1995 with assistance from a large number of cooperators who included an HPV- susceptible sweet corn hybrid in their experimental or demonstrations plantings all over the central and western plains states. Most samples were assayed by ELISA employing the antiserum to the 32 kDa N-protein. Other diagnostic methods included symptom expression on maize or wheat, assaying for the presence of the 32 kDa protein, or after the antiserum became available, conducting western blots of sample proteins separated by polyacrylamide gel electrophoresis. Polymerase chain reaction using the base sequence of RNA #3 to design primers was used to confirm the presence of HPV in some samples. Results and conclusions HPV has been positively identified in over 100 counties in 10 states throughout the High Plains and Rocky Mountain regions from eastern Nebraska to western Idaho, and from Montana and South Dakota to the panhandle of Texas. HPV-positive samples have also come from winter-grown sweet corn fields in Florida and HPV has also been identified in sweet corn samples from Chile and Brazil. HPV has been tentatively identified in samples from several other countries using only one of the methods listed above. Positive identification of HPV in those countries awaits further analysis. Reports of similar viruses have come from North Dakota, Ohio and Pennsylvania in the USA, as well as from Canada and Russia. These reports and our data suggests that HPV may be world wide in distribution. References 1.Jensen, SG, Lane, LC, Seifers, DL. 1996. Plant Disease 80,1387-1390. 2.Jensen, SG. 1996. WWW URL: http://ianrwww.unl.edu/ianr/plntpath/nematode/PPATHPER/Hpv.htm