Submitted to: National American Phytopathology Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 6/29/2009
Publication Date: 8/1/2009
Citation: Vittal, R., Chan, L., Zhang, W., Cunningham, B.T., Hartman, G.L. 2009. Label-Free Detection of Soybean Rust Spores using Photonic Crystal Biosensors [abstract]. American Phytopathological Society National Meeting, August 1-5, 2009, Portland, Oregon. 99:S136. Interpretive Summary:
Technical Abstract: Soybean rust, caused by the fungus Phakopsora pachyrhizi, is one of the most devastating foliar diseases affecting soybeans grown worldwide. The disease was reported for the first time in the United States in 2004. Early spore detection, prior to the appearance of visible symptoms, is critical to effective fungicide management strategies. We have developed a subtractive inhibition assay that involves the use of specific antibodies (both mono and poly, referred to as mAb and pAb respectively) and a photonic crystal biosensor for label-free detection of soybean rust spores. In this assay, the spores and antibodies were mixed, spore-bound antibodies removed by centrifugation, and the remaining unbound antibodies quantified using the biosensor. A detection limit of 2.5 x 105 spores/ml was achieved using an antibody concentration of 0.01 mg/ml (both mAb and pAb). The results were compared to an outgroup consisting of corn rust spores that showed the highest signal, meaning no antibody was bound to them. This may be the first step in reaching the goal of developing an economical and field-deployable detection system.