Barley stripe mosaic virus. Coloured transmission electron micrograph (TEM) of virus particles (virions) of the barley stripe mosaic virus (BSMV). This plant virus is a hordeivirus, and has an RNA (ribonucleic acid) genome. It was first identified in 1951 in barley (Hordeum) and wheat (Triticum) plants. Barley and wheat are two of the world's major cereal crops. Symptoms range from mild stripes to fatal tissue death. The virus is transmitted by pollen into the pollinated plant's seeds. Magnification: x125,000 when printed 10cm high.