Purification and properties of elm mottle virus.

Abstract

SUMMARYA virus obtained commonly from Wych elm (Ulmus glabra) in Scotland showing ringspot and line‐pattern leaf symptoms was serologically related to elm mottle virus (EMotV) from East Germany. The virus was seed‐borne in elm and was transmitted by inoculation of sap to elm and twenty‐one herbaceous species. No symptoms developed in infected elm seedlings kept in the glasshouse. In Chenopodium quinoa sap, EMotV lost infectivity after diluting to 10‐4, after 10 min at 60 oC, or 9 days at 18 oC. When purified from C. quinoa sap by clarification with n‐butanol (8‐5 %, v/v) and differential centrifugation, preparations contained quasi‐spherical particles mostly 26–29 nm m diameter (mean = 28 nm) which sedimented as three nucleo‐protein components with sedimentation coefficients (so2o, w) of 83, 88 and 1 or S; most infectivity was associated with the 101 S component but infectivity was enhanced by adding the slower sedimenting components.When centrifuged to equilibrium in caesium chloride solution at 4 oC, purified virus preparations were largely degraded and contained many non‐infective particles c. 15–22 nm in diameter, and intact infective particles which formed a band of density c. 1–34 g/cm3.Polyacrylamide gel electrophoresis indicated that EMotV contained a single major protein species of estimated mol. wt. 25000 and five RNA species of estimated mol. wt. 1–30, 1.15, 0–82, 0 39 and 0–30 times106. Gel electrophoresis of RNA extracted from the separated components indicated that the 101 S component contained 1–30 x io6 mol. wt. RNA and the 83 S component 0–82 times 106 mol. wt. RNA. In these and other properties, EMotV resembles the serologically unrelated tobacco streak virus.