RT-PCR analysis to detect BPMV in the roots of soybean plants. RNA was prepared from roots of plants at different days post virus (dpv) inoculation of leaves and used for RT-PCR analysis with BPMV-specific primers. Lanes: M, 1 kb ladder (NEB); V, BPMV only; A, BPMV-Actin. Subscripts denote the dpv. Bottom panel, soybean ubiquitin gene [Genbank:D28123] internal control.