Temporal and spatial spread of Soybean mosaic virus in soybeans transformed with the coat protein gene of SMV

Soybean mosaic virus (SMV) causes a serious disease of soybeans, and is found in all major growing regions worldwide. The virus is vectored by over 30 species of aphids in a non-persistent manner. Six soybean lines were generated by Agrobacterium-mediated transformation with the coat-protein gene of SMV strain N. Field plots of each line were established with point sources of aphid-transmissible SMV strain AL-5 in 1999 and 2000. Plots were divided into quadrants, and plant samples within quadrants were bulked together for testing by biotin-avidin ELISA. The Gompertz model was the most appropriate for quantifying and comparing the temporal spread of SMV in the six soybean lines over both years. Two lines (3-24 and 7B-11) had lower infection rates and lower final pathogen incidences, compared to the untransformed control. Ordinary runs analysis revealed clustering of infected quadrants in lines with the highest rates of pathogen progress for both years. Harvested soybeans showed significantly less seed-coat mottling in 3-24 and 7B-11, compared to the untransformed control