Arracacha virus B, a second isometric virus infecting arracacha (Arracacia xanthorrhiza; Umbelliferae) in the Peruvian Andes

Abstract

SUMMARYArracacha virus B (AVB), a previously undescribed virus, was found together with arracacha virus A or with a 750 nm flexous filamentous virus in arracacha (Arracacia Xanthorrhiza; Umbelliferae) growing in the Huanuco region of the Peruvian Andes. AVB was transmitted by inoculation of sap to 30 species from eight families out of 45 species from 10 families tested. It was transmitted through seed of Chenopodium quinoa but not by Myzus persicae. AVB was best propagated in C. Quinoa or Tetragonia expansa and assayed in C. quinoa, C. murale or C. amaranticolor. Sap from infeted <C. Quinoa was occasionally infective after dilution to 10‐4 but not 10‐5, after 10 min at 65 d̀ C but not 70 d̀ C, and after 12 but not 14 days at 20 d̀ C.In neutral phosphotungstate, AVB has isometric partilces c. 26 nm in diameter with a hexagonal profile. About 50‐ 150 A1 cm260 units of purified virus were obtained from 1 kg infected C. quinoa leaf by extraction in 0.5 M phosphate buffer at pH 7.5, containing 0.05 M ethylene‐daiminetetra‐acetate (EDTA) and 0.2% mercaptoethanol, and clarificatin with chloroform, followed by two precipitations with polyethylene glycol and three cylces of differential centrifugation. Purified virus coefficent (Sd̀20 w,) of 126 S and A260/A280 ratio of 1.80, bnut formed two isopycnic bands in CsC1 of buoyant density 1.481 and 1.492 g/cm3 with estimated nucleic acid contents of 40 and 41% respectively. AVB particles contained two proteins of mol.wt 26 000 (major component) and 20 000. AVB was not serologically related to any of 20 other morphologically similar viruses. Its properties suggest that it does not fall into any recognised group of viruses.the cryptogram of AVB is */*:*/40–41:S/S:S/*