title: Simple and portable magnetic immunoassay for rapid detection and sensitive quantification of plant viruses.
abstract: Plant pathogens cause major economic losses in the agricultural industry because late detection delays the implementation of measures that can prevent their dissemination. Sensitive and robust procedures for the rapid detection of plant pathogens are therefore required to reduce yield losses and the use of expensive, environmentally damaging chemicals. Here we describe a simple and portable system for the rapid detection of viral pathogens in infected plants based on immunofiltration, subsequent magnetic detection, and the quantification of magnetically labeled virus particles. Grapevine fanleaf virus (GFLV) was chosen as a model pathogen. Monoclonal antibodies recognizing the GFLV capsid protein were immobilized onto immunofiltration columns, and the same antibodies were linked to magnetic nanoparticles. GFLV was quantified by immunofiltration with magnetic labeling in a double-antibody sandwich configuration. A magnetic frequency mixing technique, in which a two-frequency magnetic excitation field was used to induce a sum frequency signal in the resonant detection coil, corresponding to the virus concentration within the immunofiltration column, was used for high-sensitivity quantification. We were able to measure GFLV concentrations in the range of 6 ng/ml to 20 μg/ml in less than 30 min. The magnetic immunoassay could also be adapted to detect other plant viruses, including Potato virus X and Tobacco mosaic virus, with detection limits of 2 to 60 ng/ml.
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Rettcher
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany.
authors.forename: Felicitas
authors.initials: F
authors.lastname: Jungk
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Kühn
authors.affiliation: Peter Grünberg Institute PGI-8, Research Center Jülich, Jülich, Germany.
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Krause
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany.
authors.forename: Greta
authors.initials: G
authors.lastname: Nölke
authors.affiliation: Institute for Molecular Biotechnology (Biology VII), RWTH Aachen University, Aachen, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Commandeur
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany Institute for Molecular Biotechnology (Biology VII), RWTH Aachen University, Aachen, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Fischer
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Schillberg
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany florian.schroeper@ime.fraunhofer.de.
authors.forename: Florian
authors.initials: F
authors.lastname: Schröper
mesh_terms: D018189:Immunomagnetic Separation / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry; D017860:Nepovirus / Q000302:isolation & purification*; D010935:Plant Diseases / Q000821:virology*; D017863:Potexvirus / Q000302:isolation & purification; D013997:Time Factors; D014027:Tobacco Mosaic Virus / Q000302:isolation & purification; D019562:Viral Load / Q000379:methods*