Figure 1. Each tiny well in the ELISA plate is a separate test

The test starts by adding antibodies to a special ELISA plate (Figure 1). An antibody is a protein evoked in response to a specific virus. Plant sap from the plant to be tested is added. If the virus is indeed present, the antibodies will attach to it and a detectable color reaction will occur (Figure 2).

Commercial ELISA test kits are available with antibodies for all major soybean viruses. We use the techniques for four common soybean viruses: alfalfa mosaic, soybean mosaic, bean leaf mottle and tobacco streak virus.

Figure 2. How the ELISA test works.