Rice tungro disease is caused by an RNA and a DNA virus

We present evidence that rice tungro spherical virus (RTSV) has a genome of polyadenylated single-stranded RNA of about 10 kb whereas rice tungro bacilliform virus (RTBV) contains double-stranded circular DNA. RTBV DNA has been mapped and shown to have two discontinuities, one in each strand, at specific sites; it thus resembles that of the caulimoviruses. Gel electrophoresis of RTSV preparations revealed two protein bands (Mr 35K and 26K). RTBV yielded two major protein bands of 37K and 33K together with several minor species of higher and lower Mr which react with antiviral serum.