Los virus del frijol en Centroamérica. IV. Algunas propiedades y transmisión por insectos crisomélidos del virus del moteado amarillo del frijol.

Abstract

Bean yellow stipple virus (BYSV) was isolate from beans (Phaseolus vulgaris) in Turrialba, Costa Rica. Infected plants showed a distinctive yellow stippling and slight malformation leaves BYSV infected 14 of 24 mechanically inoculated species of Leguminosae. All of 542 cultivars of beans tested were found susceptible to the virus. No species outside Leguminosae were infected. The virus was not transmitted through seed of infected plants. Properties in unbuffered sap were thermal inactivation point between 74 and 76°C, longevity in vitro at 20°C between 24 and 48 h, dilution and point between 10-3 and 10-5 BYSV was transmitted by the chrysomelid beetles Cerotoma ruficornis and Diabrotica balteata. Insects acquired the virus after feeding periods of 24 h and retained transmissibility for to 4 to 6, and 1 to 3 days respectively. The virus was purified from infected bean leaves by chloroform-butanol clarification and differential centrifugation in 0.01 M phosphate buffer, pH 7.0, and separated as a single centrifugal component after sucrose rate zonal density gradient centrifugation. Purified preparations were highly infective and contained numerous isometric particles, 26-30 um in diameter. The absorption spectrum was typical of nucleoproteins with maximum and minimum at 260-240 um, respectively. The A 260/280 was 0.60 ± 0.02 and 260/240 was 0.70 ± 02, indicating nucleic acid content of 20-22 per cent BYSV is serologically related but not homologous to cowpea chlorotic mottle virus, and is considered a strain of this virus and a member of the bromovirus group.