Effects of Temperature on BYDV Concentration in Oat Plants and Virus Purification Efficiency, and Detection of a Putative Associated Satellite Virus

RPV and MAV-like serotypes of barley yellow dwarf virus (BYDV), designated R-568 and F, were found during sucrose density gradient centrifugation to suspend at 10 °C and 4 °C but to totally sediment at 15 °C and 12 °C, respectively. These properties were used to purify these serotypes, and antisera were then prepared.
Partially purified IgG from antiserum was used in immunosorbent electron microscopy (ISEM) and in enzyme-labelled immunosorbent (ELISA) tests to detect BYDV RPV-like serotypes. Using anti-BYDV R-568 polyclonal antiserum and the BYDV R-568 serotype in ISEM tests, isometric virus particles of two sizes were trapped: the 28 nm particles of BYDV R-568, and others 17 nm in diameter which may be those of a satellite virus.
The effects of temperatures on virus concentrations in oat plants infected with BYDV serotypes F and R-568 were investigated. BYDV F and R-568 concentrations in the roots and shoots were sensitive to changes in temperature between 10 °C and 25 °C. The concentrations of both viruses in the roots and shoots of infected plants could be manipulated by varying the temperature at which plants were grown. The ELISA absorbance values related to detection of F MAV-like serotypes were higher in roots and shoots of oats grown at 10 °C than for oats grown at 25 °C. Conversely, cool temperatures reduced the absorbance values for R-568 RPV-like serotype in the roots, but less significantly in the shoots.