Purification and serological properties of rice grassy stunt virus 2H. Hibino and P. Q. Cabauatan, IRRI; and

T. Omura and T. Tsuchizaki, Institute for Plant Virus Research, Tsukuba, Ibaraki, 305 Japan

Rice grassy stunt virus 2 (RGSV 2), a strain of rice grassy stunt virus (RGSV l) transmitted by Nilaparvata lugens, was purified following the procedure for grassy stunt virus in Japan. The sap of infected plants was clarified with magnesium bentonite and carbon tetrachloride (CCl 4), treated with polyethylene glycol (PEG), and centrifuged in 10-45% sucrose density gradient. Electron microscopy of the purified fraction revealed numerous filamentous particles of various lengths (see figure). The particles were similar to grassy stunt associated filamentous particles. The ultraviolet absorption spectrum of the purified fraction was maximum at 260 nm, and minimum at 246-247 nm, which is typical of a nucleoprotein The OD 260/280 ratio was 1.29.

Antiserum to RGSV 2 was obtained by immunizing a rabbit with the purified virus. In a precipitin ring interphase test, the titer of the serum against both purified RGSV 1 and RGSV 2 was 1:640. The titer of serum to RGSV in Japan against RGSV 1 and RGSV 2 was 1: 1280 and 1:640, respectively (see table). These results confirm a previous report of the close serological relationship between RGSV1 and RGSV 2.

Electron micrograph of RGSV 2 particles – 60,000 X.

Hibino H, PQ Cabauatan, T Omura, T Tsuchizaki. 1983. Purification and serological properties of rice grassy stunt virus 2. International Rice Research Newsletter 8 (6): 11-12.