Biolistic inoculation of soybean plants with soybean dwarf virus

Soybean dwarf virus (SbDV), a member of the genus Luteovirus, has been transmitted only by aphid vectors. The possibility of using a biolistic procedure of transmitting SbDV to soybean plants without relying on aphid vectors was investigated. Biolistic inoculation using the Helios Gene Gun System with RNA transcribed in vitro from a full-length cDNA clone of the DS strain of SbDV (pSV-DS) resulted in 1/12 to 3/13 soybean plants infected systemically. The infected soybean plants showed the characteristic symptoms of SbDV-DS within 6 weeks after inoculation and the accumulation of SbDV-specific RNA species such as genomic and subgenomic RNAs in the upper non-inoculated leaves. The progeny virus derived from RNA transcribed in vitro from pSV-DS could be transmitted by aphid vectors, as is the case with native SbDV-DS. This is the first report of direct inoculation of soybean plants with SbDV without using aphid vectors.