Studies on a strain of raspberry ringspot virus occurring in England

Abstract

A strain of raspberry ringspot virus (RRV-E) infecting blackberry in Essex was transmitted by inoculation of sap to twenty-six herbaceous species, and caused symptoms in Nicandra physaloides, Datura metel and Gomphrena globosa that differentiated it from the Scottish strain of the virus (RRV-S). I n sap, with an infection end-point of I O -~, it was inactivated in 10 min. at 74' C., and in 5 weeks at 2 3 ' C. It was precipitated without inactivation by a 30 yo acetone or 30 %-saturated ammonium sulphate solution, but was inactivated when acidified to less than pH4. Partially purified preparations of RRV-E contained approximately equal amounts of three components with sedimentation rates of 50, 90 and 127s; electron micrographs of preparations mounted in neutral sodium phosphotungstate showed three kinds of particles with diameters about 30 mp but with different internal structure. A preparation of RRV-S contained a main component with a sedimentation rate of 129S, and a minor one with 50s.Petunia hybrida, cucumber and French bean seemed equally susceptible to infection with RRV-E when grown in soil containing the nematode vector Longidorus macrosoma, but inoculation of sap infected the roots of P. hybrida much more readily than roots of the other two species. Cucumber seedlings became infected when exposed for I day to infective L. macrosoma, and virus-free L. macrosoma acquired the virus from plants in 4 days. Infective L. macrosoma transmitted readily at 2 0 ' C., occasionally at 25' C., and not at 30' C.; feeding seems inhibited at 30' C. RRV-E was transmitted to seedlings grown in soil containing L. macrosoma that had been kept free from plants for 34 days. Of sixty-eight extracts of infective L. macrosoma inoculated to Chenopodium quinoa plants, only one caused infection. I N T R O D U C T I O NA virus isolated from stunted blackberry var. Himalaya Giant grown at Wakes Colne, Colchester, Essex, was shown by Cadman (1960) to be raspberry ringspot virus, but to differ serologically from the form of the virus occurring in Scotland. The English form is transmitted by the nematode Longidorus macrosoma Hooper, a species that does not transmit the Scottish form (Harrison, 1964). The experiments described here report additional information on the host range, properties and virus-vector relations of the blackberry isolate.

Properties, relationships and transmission of a strain of raspberry ringspot virus infecting raspberry cultivars immune to the common Scottish strain*

“…When a preparation was examined in the Beckman model E analytical ultracentrifuge, the Schlieren diagram (Pl., fig. 4) showed three peaks corresponding to sedimentation coefficients, S2,,+, of 50, 91 and 125, values which correspond closely with those given for RRV(E) by Debrot (1964), who also observed three zones in density gradients. The slight slope of the baseline of the Schlieren diagram was probably caused by the phytoferritin, which has been shown (Hyde et al 1963) not to sediment uniformly, but to have sedimentation coefficient values for the major component ranging between 53 and 65s.…”

Recent Studies on Strawberries

“…RpRSV can be transmitted by both species of the nematode genus Longidorus. Scottish and Dutch variants of RpRSV are most effectively transmitted by L. elongates [156], while the English variant is transmitted by L. macrosoma [157]. Other nematode species (Xiphinema diversicaudatum and other Longidorus species) were suspected to carry variants of RpRSV, but transmissions were not considered acceptable [158].…”

Isolierung des Himbeerringfleckenvirus (raspberry ringspot virus) aus Roter Johannisbeere (Ribes rubrumL.)

“…Nach KORN-GOLD (1956) VAN DER MEER (1965), der mit seiner Ribes-Herkunft iiber dem Boden Himbeeren zu infizieren vermochte, die spater Ring-fleAensymptome aufwiesen. Es muf5 jedoch betont werden, dafJ die einzelnen HRV-Isolate sich mit Hilfe der Wirtsreaktion (CADMAN 1960, HARRISON 1961, DEBROT 1964, VAN DER MEER 1965 sowie an Hand von Pramunitatsversuchen (VAN DER MEER 1965) bzw. von serologischen Testen (CADMAN 1960, HARRISON 1964, MAAT 1965 differenzieren lieften, wobei haufig auch Herkiinfte aus der gleichen Pflanzenspezies Unterschiede zeigten.…”