Biological properties of isolates of Triticum mosaic virus from the Great Plains states of the USA

Triticum mosaic virus (TriMV) is a recently discovered virus infecting wheat. A total of 170 isolates of TriMV, collected in 2010 and 2011 from wheat (Triticum aestivum L) or jointed goatgrass (Aegilops cylindrica Host) from Colorado, Kansas, Nebraska and South Dakota, were compared with the 06-123 Kansas isolate. These isolates were compared for the percentage of infected plants in N28Ht maize, Gallatin barley and Mace wheat (with temperature- sensitive resistance to Wheat streak mosaic virus (WSMV). The isolates were also compared for the effect of inoculum virus titre on the percentage of infected plants in WSMV-susceptible Tomahawk wheat by mechanically inoculating the cultivar using 1:10 w/v, 1:300 v/v or 1:600 v/v dilutions of extracts. None of the isolates infected N28Ht maize but all isolates infected Gallatin barley, Mace and Tomahawk wheat. Some isolates from Colorado, Kansas and Nebraska had low relative titre in wheat compared with the 06-123 isolate. This information is important in critical selection of TriMV isolates for use in greenhouse and field studies and in resistance screening protocols.