Mechanical Transmission, Purification, and Some Properties of Whitefly-Borne Mung Bean Yellow Mosaic Virus in Thailand

Abstract

The whitefly-borne mung bean yellow mosaic virus (MYMV) in Thailand was transmitted by mechanical inoculation. Among the several buffers used in attempted transmissions, 0.1 M potassium or sodium phosphate, pH 7.8, gave the highest transmission rates. The optimal incubation temperatures for symptom expression ranged from 25-30.degree. C in the growth chamber or 30.degree. C in the daytime and 20.degree. C at night in the greenhouse. Host range of MYMV was limited to 7 plant species in the family Leguminosae. Determinations of the stability of the virus in plant sap gave the following results: thermal inactivation point of 40.degree.-50.degree. C for 10 min, dilution end point of 10-2-10-3 and longevity in vitro of 1-2 days at 20.degree. C. Purified virus preparations had an UV light absorption spectrum typical of that of nucleoprotein with a A260/A280 value of .apprx. 1.3-1.4. Purified preparations and leaf-dip samples contained geminate particles of .apprx. 18 .times. 30 nm. Infectivity was associated with the presence of purified virus particles.