SEQUENCE-ANALYSIS OF WHEAT AND OAT FUROVIRUS CAPSID PROTEIN GENES SUGGESTS THAT OAT GOLDEN STRIPE VIRUS IS A STRAIN OF SOIL-BORNE WHEAT MOSAIC-VIRUS

In northern blots, cDNA probes prepared to soil-borne wheat mosaic vir us (SBWMV) RNA-1 and RNA-2 hybridized to RNA-1 and RNA-2, respectively , from a UK isolate of oat golden stripe virus (OGSV), as well as to t heir homologous RNAs. RT-PCR was used to amplify, clone and sequence a region of about 750 nucleotides spanning the capsid protein gene and part of the readthrough protein on RNA-2 from OGSV, a French isolate o f SBWMV and two stable deletion mutants (Lab1 and Okl-7) of SBWMV isol ates from Nebraska and Oklahoma respectively. There was very high (96. 7-99.1%) nucleotide homology between all these sequences and the wild- type SBWMV sequences from Nebraska and Oklahoma. OGSV was more similar to SBWMV from France and Nebraska than were any of the isolates to SB WMV from Oklahoma. Of the few differences in the deduced amino acid se quences of the capsid proteins from the different isolates, OGSV diffe red from all SBWMV isolates only in one amino acid (isoleucine for val ine at position 88). The high degree of similarity suggests that OGSV may best be classified as an oat strain of SBWMV.