Biological and molecular characterization and phylogenetic analysis of an Iranian isolate of High Plains wheat mosaic virus

Abstract High Plains wheat mosaic virus (HPWMoV) is an eriophyid‐mite transmitted virus infecting a number of cereals and grasses worldwide. HPWMoV has recently been reported in Iran; therefore, a comprehensive study was required to elucidate the molecular and biological characteristics of this newly identified virus. In this study, the whole genome sequence, transmission efficiency and partial host range of an Iranian isolate of HPWMoV (HPWMoV‐Ir) were determined. Moreover, a survey was conducted to understand the occurrence of wheat curl mite‐transmitted HPWMoV, wheat streak mosaic virus (WSMV), Triticum mosaic virus (TriMV) and brome streak mosaic virus (BrSMV) as mite‐borne viruses in wheat fields located in central regions of Iran. During a survey of mite‐transmitted viruses, we found that mixed infections of HPWMoV and WSMV (43.7%) were more prevalent than their single infections, while all samples were negative for TriMV and BrSMV. Moreover, other grasses, such as maize, barley, wall barley, oat, rye, Johnson grass and millet, were naturally and experimentally infected with HPWMoV‐Ir at high efficiency. HPWMoV‐Ir was transmitted to wheat by Aceria tosichella with 43% efficiency, which was similar to the transmission rate of HPWMoV in a mixed infection with WSMV. The complete genome sequence comparisons of HPWMoV‐Ir with other HPWMoV isolates showed identities ranging from 79.5% to 98.1%. Remarkably, HPWMoV‐Ir possessed a single variant of the sequence and did not show any heterogeneity in its nucleocapsid protein gene. Phylogenetic analysis of the eight genomic RNA segments positioned HPWMoV‐Ir in group B with isolates from the Midwestern United States and Australia. This discovery can assist researchers in more effectively mitigating the pathogen risks through accurate diagnosis and timely management of the disease.