Prunus necrotic ring spot virus (PNRSV) and grapevine fanleaf virus (GFLV) were detected by fluoroimmunoassay using bacterial magnetic particles (BMPs), and a double antibody sandwich enzyme linked immunosorbent assay (DAS-ELISA). For the fluoroimmunoassay, fluorescein isothiocyanate labeled anti-PNRSV antibody or anti-GFLV antibody was conjugated onto BMPs of Magnetospirillum gryphiswaldense MSR-1. With this method, a very low minimum antigen concentration (1 × 106 dilution of the original sample concentration) could be detected. Using DAS-ELISA, the minimum antigen detection concentration was the original sample concentration. Thus, comparing these two methods, a BMP-based method could increase the sensitivity up to six orders of magnitude (106) higher than an ELISA-based method of detection PNRSV and GFLV.
Chen JF, Li Y, Wang ZF, Li JL, Jiang W, Li SH (2009) High-sensitivity detection of fruit tree viruses using bacterial magnetic particles. J. Integr. Plant Biol. 51(4), 409-413.