Electron micrograph of purified Barley yellow dwarf virus (BYDV) GAV particles. Virus particles were purified from the BYDV GAV-infected wheat plant tissues through differential centrifugation. Purified virus samples were loaded on formvar-coated grids, negatively stained with 2 % (w/v, g · mL−1) phosphotungstic acid and examined under an electron microscope. Bar = 50 nm