Model PLRV - Symptomatic Potato Leaves Magnetic Strip
The rapid assay PLRV AgriStrip-magnetic is produced by BIOREBA for identification of PLRV in symptomatic potato leaves. Symptoms of primary infection consist typically of pale yellowish leaves, and in some cultivars, reddening of the tip leaves which may become rolled and assume an erect habit. Secondary symptoms, in plants grown from infected tubers, are stunting of the shoots and upward rolling of leaves.
The innovative rapid assay PLRV AgriStrip-magnetic, developed and produced by BIOREBA, is a lateral-flow immunochromatographic test based on an antigen-antibody reaction combined with Magnetic Bead Technology, enabling the preceding enrichment of the antigen.
Potato leaf extract is first incubated with magnetic beads coated with antibodies specific for PLRV. These beads are then separated from the extract with a magnet and resuspended in a small volume of running buffer. Finally, the concentrated beads migrate upwards through the strip and brown colored lines become visible. Both test and control lines become visible with positive extracts (containing PLRV), whereas negative samples produce only the upper control line (Fig. A). Intense coloration is reached within 10-20 min. and the result can be registered.
Specificity and sensitivity
The PLRV AgriStrip-magnetic assay is based on mono- and polyclonal antibodies and reacts specifically with PLRV. No cross-reaction is observed with other potato viruses. Strongest coloration of test bands is obtained with a 1:30 (w/v) dilution of an extract of infected potato leaves.
The sensitivity attained with the AgriStrip lateral flow is comparable to the sensitivity in the DAS-ELISA method, meaning that both weakly and strongly infected samples are clearly detected with both methods. Evaluation studies of several European laboratories involved in seed potato certification revealed an accordance of 100% between the two test formats with field samples.